v2026_07_28

Internal wire-shape models for protocol 2026-07-28. Generated; do not edit.

Regenerate with scripts/gen_surface_types.py from schema/2026-07-28.json (sha256 ed1ad4ba94aaeb2068b78969ef901b1150f7b2f06cf86472b3032abee1380b6a).

BaseMetadata

Bases: WireModel

Base interface for metadata with name (identifier) and title (display name) properties.

Source code in src/mcp/types/v2026_07_28/__init__.py

class BaseMetadata(WireModel):
    """
    Base interface for metadata with name (identifier) and title (display name) properties.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

Argument

Bases: WireModel

The argument's information

Source code in src/mcp/types/v2026_07_28/__init__.py

class Argument(WireModel):
    """
    The argument's information
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    name: str
    """
    The name of the argument
    """
    value: str
    """
    The value of the argument to use for completion matching.
    """

name instance-attribute

name: str

The name of the argument

value instance-attribute

value: str

The value of the argument to use for completion matching.

Context

Bases: WireModel

Additional, optional context for completions

Source code in src/mcp/types/v2026_07_28/__init__.py

class Context(WireModel):
    """
    Additional, optional context for completions
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    arguments: dict[str, str] | None = None
    """
    Previously-resolved variables in a URI template or prompt.
    """

arguments class-attribute instance-attribute

arguments: dict[str, str] | None = None

Previously-resolved variables in a URI template or prompt.

Completion

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class Completion(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    has_more: Annotated[bool | None, Field(alias="hasMore")] = None
    """
    Indicates whether there are additional completion options beyond those provided in the current response, even if the exact total is unknown.
    """
    total: int | None = None
    """
    The total number of completion options available. This can exceed the number of values actually sent in the response.
    """
    values: Annotated[list[str], Field(max_length=100)]
    """
    An array of completion values. Must not exceed 100 items.
    """

has_more class-attribute instance-attribute

has_more: Annotated[bool | None, Field(alias="hasMore")] = (
    None
)

Indicates whether there are additional completion options beyond those provided in the current response, even if the exact total is unknown.

total class-attribute instance-attribute

total: int | None = None

The total number of completion options available. This can exceed the number of values actually sent in the response.

values instance-attribute

values: Annotated[list[str], Field(max_length=100)]

An array of completion values. Must not exceed 100 items.

Cursor

Bases: RootModel[str]

Source code in src/mcp/types/v2026_07_28/__init__.py

class Cursor(RootModel[str]):
    root: str
    """
    An opaque token used to represent a cursor for pagination.
    """

root instance-attribute

root: str

An opaque token used to represent a cursor for pagination.

RequestedSchema

Bases: WireModel

A restricted subset of JSON Schema. Only top-level properties are allowed, without nesting.

Source code in src/mcp/types/v2026_07_28/__init__.py

class RequestedSchema(WireModel):
    """
    A restricted subset of JSON Schema.
    Only top-level properties are allowed, without nesting.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    schema_: Annotated[str | None, Field(alias="$schema")] = None
    properties: dict[str, Any]
    required: list[str] | None = None
    type: Literal["object"]

ElicitRequestFormParams

Bases: WireModel

The parameters for a request to elicit non-sensitive information from the user via a form in the client.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ElicitRequestFormParams(WireModel):
    """
    The parameters for a request to elicit non-sensitive information from the user via a form in the client.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    message: str
    """
    The message to present to the user describing what information is being requested.
    """
    mode: Literal["form"] = "form"
    """
    The elicitation mode.
    """
    requested_schema: Annotated[RequestedSchema, Field(alias="requestedSchema")]
    """
    A restricted subset of JSON Schema.
    Only top-level properties are allowed, without nesting.
    """

message instance-attribute

message: str

The message to present to the user describing what information is being requested.

mode class-attribute instance-attribute

mode: Literal['form'] = 'form'

The elicitation mode.

requested_schema instance-attribute

requested_schema: Annotated[
    RequestedSchema, Field(alias="requestedSchema")
]

A restricted subset of JSON Schema. Only top-level properties are allowed, without nesting.

ElicitRequestURLParams

Bases: WireModel

The parameters for a request to elicit information from the user via a URL in the client.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ElicitRequestURLParams(WireModel):
    """
    The parameters for a request to elicit information from the user via a URL in the client.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    message: str
    """
    The message to present to the user explaining why the interaction is needed.
    """
    mode: Literal["url"]
    """
    The elicitation mode.
    """
    url: str
    """
    The URL that the user should navigate to.
    """

message instance-attribute

message: str

The message to present to the user explaining why the interaction is needed.

mode instance-attribute

mode: Literal['url']

The elicitation mode.

url instance-attribute

url: str

The URL that the user should navigate to.

ElicitResult

Bases: WireModel

The result returned by the client for an {@link ElicitRequestelicitation/create} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ElicitResult(WireModel):
    """
    The result returned by the client for an {@link ElicitRequestelicitation/create} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    action: Literal["accept", "cancel", "decline"]
    """
    The user action in response to the elicitation.
    - `"accept"`: User submitted the form/confirmed the action
    - `"decline"`: User explicitly declined the action
    - `"cancel"`: User dismissed without making an explicit choice
    """
    content: dict[str, list[str] | str | int | float | bool | None] | None = None
    """
    The submitted form data, only present when action is `"accept"` and mode was `"form"`.
    Contains values matching the requested schema.
    Omitted for out-of-band mode responses.
    """

action instance-attribute

action: Literal['accept', 'cancel', 'decline']

The user action in response to the elicitation. - "accept": User submitted the form/confirmed the action - "decline": User explicitly declined the action - "cancel": User dismissed without making an explicit choice

content class-attribute instance-attribute

content: (
    dict[str, list[str] | str | int | float | bool | None]
    | None
) = None

The submitted form data, only present when action is "accept" and mode was "form". Contains values matching the requested schema. Omitted for out-of-band mode responses.

Error

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class Error(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    code: int
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: int

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

Error1

Bases: Error

Source code in src/mcp/types/v2026_07_28/__init__.py

class Error1(Error):
    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32020]
    """
    The error type that occurred.
    """

code instance-attribute

code: Literal[-32020]

The error type that occurred.

Icon

Bases: WireModel

An optionally-sized icon that can be displayed in a user interface.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Icon(WireModel):
    """
    An optionally-sized icon that can be displayed in a user interface.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    Optional MIME type override if the source MIME type is missing or generic.
    For example: `"image/png"`, `"image/jpeg"`, or `"image/svg+xml"`.
    """
    sizes: list[str] | None = None
    """
    Optional array of strings that specify sizes at which the icon can be used.
    Each string should be in WxH format (e.g., `"48x48"`, `"96x96"`) or `"any"` for scalable formats like SVG.

    If not provided, the client should assume that the icon can be used at any size.
    """
    src: str
    """
    A standard URI pointing to an icon resource. May be an HTTP/HTTPS URL or a
    `data:` URI with Base64-encoded image data.

    Consumers SHOULD take steps to ensure URLs serving icons are from the
    same domain as the client/server or a trusted domain.

    Consumers SHOULD take appropriate precautions when consuming SVGs as they can contain
    executable JavaScript.
    """
    theme: Literal["dark", "light"] | None = None
    """
    Optional specifier for the theme this icon is designed for. `"light"` indicates
    the icon is designed to be used with a light background, and `"dark"` indicates
    the icon is designed to be used with a dark background.

    If not provided, the client should assume the icon can be used with any theme.
    """

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

Optional MIME type override if the source MIME type is missing or generic. For example: "image/png", "image/jpeg", or "image/svg+xml".

sizes class-attribute instance-attribute

sizes: list[str] | None = None

Optional array of strings that specify sizes at which the icon can be used. Each string should be in WxH format (e.g., "48x48", "96x96") or "any" for scalable formats like SVG.

If not provided, the client should assume that the icon can be used at any size.

src instance-attribute

src: str

A standard URI pointing to an icon resource. May be an HTTP/HTTPS URL or a data: URI with Base64-encoded image data.

Consumers SHOULD take steps to ensure URLs serving icons are from the same domain as the client/server or a trusted domain.

Consumers SHOULD take appropriate precautions when consuming SVGs as they can contain executable JavaScript.

theme class-attribute instance-attribute

theme: Literal['dark', 'light'] | None = None

Optional specifier for the theme this icon is designed for. "light" indicates the icon is designed to be used with a light background, and "dark" indicates the icon is designed to be used with a dark background.

If not provided, the client should assume the icon can be used with any theme.

Icons

Bases: WireModel

Base interface to add icons property.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Icons(WireModel):
    """
    Base interface to add `icons` property.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

Implementation

Bases: WireModel

Describes the MCP implementation.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Implementation(WireModel):
    """
    Describes the MCP implementation.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    description: str | None = None
    """
    An optional human-readable description of what this implementation does.

    This can be used by clients or servers to provide context about their purpose
    and capabilities. For example, a server might describe the types of resources
    or tools it provides, while a client might describe its intended use case.
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """
    version: str
    """
    The version of this implementation.
    """
    website_url: Annotated[str | None, Field(alias="websiteUrl")] = None
    """
    An optional URL of the website for this implementation.
    """

description class-attribute instance-attribute

description: str | None = None

An optional human-readable description of what this implementation does.

This can be used by clients or servers to provide context about their purpose and capabilities. For example, a server might describe the types of resources or tools it provides, while a client might describe its intended use case.

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

version instance-attribute

version: str

The version of this implementation.

website_url class-attribute instance-attribute

website_url: Annotated[
    str | None, Field(alias="websiteUrl")
] = None

An optional URL of the website for this implementation.

InternalError

Bases: WireModel

A JSON-RPC error indicating that an internal error occurred on the receiver. This error is returned when the receiver encounters an unexpected condition that prevents it from fulfilling the request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class InternalError(WireModel):
    """
    A JSON-RPC error indicating that an internal error occurred on the receiver. This error is returned when the receiver encounters an unexpected condition that prevents it from fulfilling the request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32603]
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: Literal[-32603]

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

InvalidParamsError

Bases: WireModel

A JSON-RPC error indicating that the method parameters are invalid or malformed.

In MCP, this error is returned in various contexts when request parameters fail validation:

• Tools: Unknown tool name or invalid tool arguments
• Prompts: Unknown prompt name or missing required arguments
• Pagination: Invalid or expired cursor values
• Logging: Invalid log level
• Elicitation: Server requests an elicitation mode not declared in client capabilities
• Sampling: Missing tool result or tool results mixed with other content

Source code in src/mcp/types/v2026_07_28/__init__.py

class InvalidParamsError(WireModel):
    """
    A JSON-RPC error indicating that the method parameters are invalid or malformed.

    In MCP, this error is returned in various contexts when request parameters fail validation:

    - **Tools**: Unknown tool name or invalid tool arguments
    - **Prompts**: Unknown prompt name or missing required arguments
    - **Pagination**: Invalid or expired cursor values
    - **Logging**: Invalid log level
    - **Elicitation**: Server requests an elicitation mode not declared in client capabilities
    - **Sampling**: Missing tool result or tool results mixed with other content
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32602]
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: Literal[-32602]

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

InvalidRequestError

Bases: WireModel

A JSON-RPC error indicating that the request is not a valid request object. This error is returned when the message structure does not conform to the JSON-RPC 2.0 specification requirements for a request (e.g., missing required fields like jsonrpc or method, or using invalid types for these fields).

Source code in src/mcp/types/v2026_07_28/__init__.py

class InvalidRequestError(WireModel):
    """
    A JSON-RPC error indicating that the request is not a valid request object. This error is returned when the message structure does not conform to the JSON-RPC 2.0 specification requirements for a request (e.g., missing required fields like `jsonrpc` or `method`, or using invalid types for these fields).
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32600]
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: Literal[-32600]

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

JSONRPCNotification

Bases: WireModel

A notification which does not expect a response.

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCNotification(WireModel):
    """
    A notification which does not expect a response.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: str
    params: dict[str, Any] | None = None

LegacyTitledEnumSchema

Bases: WireModel

Use {@link TitledSingleSelectEnumSchema} instead. This interface will be removed in a future version.

Source code in src/mcp/types/v2026_07_28/__init__.py

class LegacyTitledEnumSchema(WireModel):
    """
    Use {@link TitledSingleSelectEnumSchema} instead.
    This interface will be removed in a future version.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    default: str | None = None
    description: str | None = None
    enum: list[str]
    enum_names: Annotated[list[str] | None, Field(alias="enumNames")] = None
    """
    (Legacy) Display names for enum values.
    Non-standard according to JSON schema 2020-12.
    """
    title: str | None = None
    type: Literal["string"]

enum_names class-attribute instance-attribute

enum_names: Annotated[
    list[str] | None, Field(alias="enumNames")
] = None

(Legacy) Display names for enum values. Non-standard according to JSON schema 2020-12.

LoggingLevel

Bases: RootModel[Literal['alert', 'critical', 'debug', 'emergency', 'error', 'info', 'notice', 'warning']]

Source code in src/mcp/types/v2026_07_28/__init__.py

class LoggingLevel(
    RootModel[
        Literal[
            "alert",
            "critical",
            "debug",
            "emergency",
            "error",
            "info",
            "notice",
            "warning",
        ]
    ]
):
    root: Literal["alert", "critical", "debug", "emergency", "error", "info", "notice", "warning"]
    """
    The severity of a log message.

    These map to syslog message severities, as specified in RFC-5424:
    https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1
    """

root instance-attribute

root: Literal[
    "alert",
    "critical",
    "debug",
    "emergency",
    "error",
    "info",
    "notice",
    "warning",
]

The severity of a log message.

These map to syslog message severities, as specified in RFC-5424: https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1

MetaObject

Bases: WireModel

Represents the contents of a _meta field, which clients and servers use to attach additional metadata to their interactions.

Certain key names are reserved by MCP for protocol-level metadata; implementations MUST NOT make assumptions about values at these keys. Additionally, specific schema definitions may reserve particular names for purpose-specific metadata, as declared in those definitions.

Valid keys have two segments:

Prefix: - Optional — if specified, MUST be a series of labels separated by dots (.), followed by a slash (/). - Labels MUST start with a letter and end with a letter or digit. Interior characters may be letters, digits, or hyphens (-). - Implementations SHOULD use reverse DNS notation (e.g., com.example/ rather than example.com/). - Any prefix where the second label is modelcontextprotocol or mcp is reserved for MCP use. For example: io.modelcontextprotocol/, dev.mcp/, org.modelcontextprotocol.api/, and com.mcp.tools/ are all reserved. However, com.example.mcp/ is NOT reserved, as the second label is example.

Name: - Unless empty, MUST start and end with an alphanumeric character ([a-z0-9A-Z]). - Interior characters may be alphanumeric, hyphens (-), underscores (_), or dots (.).

Source code in src/mcp/types/v2026_07_28/__init__.py

class MetaObject(WireModel):
    """
    Represents the contents of a `_meta` field, which clients and servers use to attach additional metadata to their interactions.

    Certain key names are reserved by MCP for protocol-level metadata; implementations MUST NOT make assumptions about values at these keys. Additionally, specific schema definitions may reserve particular names for purpose-specific metadata, as declared in those definitions.

    Valid keys have two segments:

    **Prefix:**
    - Optional — if specified, MUST be a series of _labels_ separated by dots (`.`), followed by a slash (`/`).
    - Labels MUST start with a letter and end with a letter or digit. Interior characters may be letters, digits, or hyphens (`-`).
    - Implementations SHOULD use reverse DNS notation (e.g., `com.example/` rather than `example.com/`).
    - Any prefix where the second label is `modelcontextprotocol` or `mcp` is **reserved** for MCP use. For example: `io.modelcontextprotocol/`, `dev.mcp/`, `org.modelcontextprotocol.api/`, and `com.mcp.tools/` are all reserved. However, `com.example.mcp/` is NOT reserved, as the second label is `example`.

    **Name:**
    - Unless empty, MUST start and end with an alphanumeric character (`[a-z0-9A-Z]`).
    - Interior characters may be alphanumeric, hyphens (`-`), underscores (`_`), or dots (`.`).
    """

    model_config = ConfigDict(
        extra="allow",
    )

MethodNotFoundError

Bases: WireModel

A JSON-RPC error indicating that the requested method does not exist or is not available.

In MCP, a server returns this error when a client invokes a method the server does not implement — either a genuinely unknown method, or one gated behind a server capability the server did not advertise (e.g., calling prompts/list when the prompts capability was not advertised).

A request that requires a client capability the client did not declare is signalled instead by {@link MissingRequiredClientCapabilityError} (-32021).

Source code in src/mcp/types/v2026_07_28/__init__.py

class MethodNotFoundError(WireModel):
    """
    A JSON-RPC error indicating that the requested method does not exist or is not available.

    In MCP, a server returns this error when a client invokes a method the server does not implement — either a genuinely unknown method, or one gated behind a server capability the server did not advertise (e.g., calling `prompts/list` when the `prompts` capability was not advertised).

    A request that requires a client capability the client did not declare is signalled instead by {@link MissingRequiredClientCapabilityError} (`-32021`).
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32601]
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: Literal[-32601]

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

ModelHint

Bases: WireModel

Hints to use for model selection.

Keys not declared here are currently left unspecified by the spec and are up to the client to interpret.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ModelHint(WireModel):
    """
    Hints to use for model selection.

    Keys not declared here are currently left unspecified by the spec and are up
    to the client to interpret.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    name: str | None = None
    """
    A hint for a model name.

    The client SHOULD treat this as a substring of a model name; for example:
     - `claude-3-5-sonnet` should match `claude-3-5-sonnet-20241022`
     - `sonnet` should match `claude-3-5-sonnet-20241022`, `claude-3-sonnet-20240229`, etc.
     - `claude` should match any Claude model

    The client MAY also map the string to a different provider's model name or a different model family, as long as it fills a similar niche; for example:
     - `gemini-1.5-flash` could match `claude-3-haiku-20240307`
    """

name class-attribute instance-attribute

name: str | None = None

A hint for a model name.

The client SHOULD treat this as a substring of a model name; for example: - claude-3-5-sonnet should match claude-3-5-sonnet-20241022 - sonnet should match claude-3-5-sonnet-20241022, claude-3-sonnet-20240229, etc. - claude should match any Claude model

The client MAY also map the string to a different provider's model name or a different model family, as long as it fills a similar niche; for example: - gemini-1.5-flash could match claude-3-haiku-20240307

ModelPreferences

Bases: WireModel

The server's preferences for model selection, requested of the client during sampling.

Because LLMs can vary along multiple dimensions, choosing the "best" model is rarely straightforward. Different models excel in different areas—some are faster but less capable, others are more capable but more expensive, and so on. This interface allows servers to express their priorities across multiple dimensions to help clients make an appropriate selection for their use case.

These preferences are always advisory. The client MAY ignore them. It is also up to the client to decide how to interpret these preferences and how to balance them against other considerations.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ModelPreferences(WireModel):
    """
    The server's preferences for model selection, requested of the client during sampling.

    Because LLMs can vary along multiple dimensions, choosing the "best" model is
    rarely straightforward.  Different models excel in different areas—some are
    faster but less capable, others are more capable but more expensive, and so
    on. This interface allows servers to express their priorities across multiple
    dimensions to help clients make an appropriate selection for their use case.

    These preferences are always advisory. The client MAY ignore them. It is also
    up to the client to decide how to interpret these preferences and how to
    balance them against other considerations.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    cost_priority: Annotated[float | None, Field(alias="costPriority", ge=0.0, le=1.0)] = None
    """
    How much to prioritize cost when selecting a model. A value of 0 means cost
    is not important, while a value of 1 means cost is the most important
    factor.
    """
    hints: list[ModelHint] | None = None
    """
    Optional hints to use for model selection.

    If multiple hints are specified, the client MUST evaluate them in order
    (such that the first match is taken).

    The client SHOULD prioritize these hints over the numeric priorities, but
    MAY still use the priorities to select from ambiguous matches.
    """
    intelligence_priority: Annotated[float | None, Field(alias="intelligencePriority", ge=0.0, le=1.0)] = None
    """
    How much to prioritize intelligence and capabilities when selecting a
    model. A value of 0 means intelligence is not important, while a value of 1
    means intelligence is the most important factor.
    """
    speed_priority: Annotated[float | None, Field(alias="speedPriority", ge=0.0, le=1.0)] = None
    """
    How much to prioritize sampling speed (latency) when selecting a model. A
    value of 0 means speed is not important, while a value of 1 means speed is
    the most important factor.
    """

cost_priority class-attribute instance-attribute

cost_priority: Annotated[
    float | None,
    Field(alias="costPriority", ge=0.0, le=1.0),
] = None

How much to prioritize cost when selecting a model. A value of 0 means cost is not important, while a value of 1 means cost is the most important factor.

hints class-attribute instance-attribute

hints: list[ModelHint] | None = None

Optional hints to use for model selection.

If multiple hints are specified, the client MUST evaluate them in order (such that the first match is taken).

The client SHOULD prioritize these hints over the numeric priorities, but MAY still use the priorities to select from ambiguous matches.

intelligence_priority class-attribute instance-attribute

intelligence_priority: Annotated[
    float | None,
    Field(alias="intelligencePriority", ge=0.0, le=1.0),
] = None

How much to prioritize intelligence and capabilities when selecting a model. A value of 0 means intelligence is not important, while a value of 1 means intelligence is the most important factor.

speed_priority class-attribute instance-attribute

speed_priority: Annotated[
    float | None,
    Field(alias="speedPriority", ge=0.0, le=1.0),
] = None

How much to prioritize sampling speed (latency) when selecting a model. A value of 0 means speed is not important, while a value of 1 means speed is the most important factor.

PaginatedResult

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class PaginatedResult(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    next_cursor: Annotated[str | None, Field(alias="nextCursor")] = None
    """
    An opaque token representing the pagination position after the last returned result.
    If present, there may be more results available.
    """
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """

next_cursor class-attribute instance-attribute

next_cursor: Annotated[
    str | None, Field(alias="nextCursor")
] = None

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ParseError

Bases: WireModel

A JSON-RPC error indicating that invalid JSON was received by the server. This error is returned when the server cannot parse the JSON text of a message.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ParseError(WireModel):
    """
    A JSON-RPC error indicating that invalid JSON was received by the server. This error is returned when the server cannot parse the JSON text of a message.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32700]
    """
    The error type that occurred.
    """
    data: Any | None = None
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """
    message: str
    """
    A short description of the error. The message SHOULD be limited to a concise single sentence.
    """

code instance-attribute

code: Literal[-32700]

The error type that occurred.

data class-attribute instance-attribute

data: Any | None = None

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message instance-attribute

message: str

A short description of the error. The message SHOULD be limited to a concise single sentence.

ProgressToken

Bases: RootModel[str | int]

Source code in src/mcp/types/v2026_07_28/__init__.py

class ProgressToken(RootModel[str | int]):
    root: str | int
    """
    A progress token, used to associate progress notifications with the original request.
    """

root instance-attribute

root: str | int

A progress token, used to associate progress notifications with the original request.

PromptArgument

Bases: WireModel

Describes an argument that a prompt can accept.

Source code in src/mcp/types/v2026_07_28/__init__.py

class PromptArgument(WireModel):
    """
    Describes an argument that a prompt can accept.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    description: str | None = None
    """
    A human-readable description of the argument.
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    required: bool | None = None
    """
    Whether this argument must be provided.
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """

description class-attribute instance-attribute

description: str | None = None

A human-readable description of the argument.

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

required class-attribute instance-attribute

required: bool | None = None

Whether this argument must be provided.

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

PromptReference

Bases: WireModel

Identifies a prompt.

Source code in src/mcp/types/v2026_07_28/__init__.py

class PromptReference(WireModel):
    """
    Identifies a prompt.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """
    type: Literal["ref/prompt"]

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

RequestId

Bases: RootModel[str | int]

Source code in src/mcp/types/v2026_07_28/__init__.py

class RequestId(RootModel[str | int]):
    root: str | int
    """
    A uniquely identifying ID for a request in JSON-RPC.
    """

root instance-attribute

root: str | int

A uniquely identifying ID for a request in JSON-RPC.

ResourceContents

Bases: WireModel

The contents of a specific resource or sub-resource.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceContents(WireModel):
    """
    The contents of a specific resource or sub-resource.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type of this resource, if known.
    """
    uri: str
    """
    The URI of this resource.
    """

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type of this resource, if known.

uri instance-attribute

uri: str

The URI of this resource.

ResourceTemplateReference

Bases: WireModel

A reference to a resource or resource template definition.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceTemplateReference(WireModel):
    """
    A reference to a resource or resource template definition.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    type: Literal["ref/resource"]
    uri: str
    """
    The URI or URI template of the resource.
    """

uri instance-attribute

uri: str

The URI or URI template of the resource.

Result

Bases: WireModel

Common result fields.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Result(WireModel):
    """
    Common result fields.
    """

    model_config = ConfigDict(
        extra="allow",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ResultType

Bases: RootModel[str]

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResultType(RootModel[str]):
    root: str
    """
    Indicates the type of a {@link Result} object, allowing the client to
    determine how to parse the response.

    complete - the request completed successfully and the result contains the final content.
    input_required - the request requires additional input and the result contains an {@link InputRequiredResult} object with instructions for the client to provide additional input before retrying the original request.
    """

root instance-attribute

root: str

Indicates the type of a {@link Result} object, allowing the client to determine how to parse the response.

complete - the request completed successfully and the result contains the final content. input_required - the request requires additional input and the result contains an {@link InputRequiredResult} object with instructions for the client to provide additional input before retrying the original request.

Role

Bases: RootModel[Literal['assistant', 'user']]

Source code in src/mcp/types/v2026_07_28/__init__.py

class Role(RootModel[Literal["assistant", "user"]]):
    root: Literal["assistant", "user"]
    """
    The sender or recipient of messages and data in a conversation.
    """

root instance-attribute

root: Literal['assistant', 'user']

The sender or recipient of messages and data in a conversation.

Root

Bases: WireModel

Represents a root directory or file that the server can operate on.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Root(WireModel):
    """
    Represents a root directory or file that the server can operate on.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    name: str | None = None
    """
    An optional name for the root. This can be used to provide a human-readable
    identifier for the root, which may be useful for display purposes or for
    referencing the root in other parts of the application.
    """
    uri: str
    """
    The URI identifying the root. This *must* start with `file://` for now.
    This restriction may be relaxed in future versions of the protocol to allow
    other URI schemes.
    """

name class-attribute instance-attribute

name: str | None = None

An optional name for the root. This can be used to provide a human-readable identifier for the root, which may be useful for display purposes or for referencing the root in other parts of the application.

uri instance-attribute

uri: str

The URI identifying the root. This must start with file:// for now. This restriction may be relaxed in future versions of the protocol to allow other URI schemes.

Prompts

Bases: WireModel

Present if the server offers any prompt templates.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Prompts(WireModel):
    """
    Present if the server offers any prompt templates.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    list_changed: Annotated[bool | None, Field(alias="listChanged")] = None
    """
    Whether this server supports notifications for changes to the prompt list.
    """

list_changed class-attribute instance-attribute

list_changed: Annotated[
    bool | None, Field(alias="listChanged")
] = None

Whether this server supports notifications for changes to the prompt list.

Resources

Bases: WireModel

Present if the server offers any resources to read.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Resources(WireModel):
    """
    Present if the server offers any resources to read.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    list_changed: Annotated[bool | None, Field(alias="listChanged")] = None
    """
    Whether this server supports notifications for changes to the resource list.
    """
    subscribe: bool | None = None
    """
    Whether this server supports subscribing to resource updates.
    """

list_changed class-attribute instance-attribute

list_changed: Annotated[
    bool | None, Field(alias="listChanged")
] = None

Whether this server supports notifications for changes to the resource list.

subscribe class-attribute instance-attribute

subscribe: bool | None = None

Whether this server supports subscribing to resource updates.

Tools

Bases: WireModel

Present if the server offers any tools to call.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Tools(WireModel):
    """
    Present if the server offers any tools to call.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    list_changed: Annotated[bool | None, Field(alias="listChanged")] = None
    """
    Whether this server supports notifications for changes to the tool list.
    """

list_changed class-attribute instance-attribute

list_changed: Annotated[
    bool | None, Field(alias="listChanged")
] = None

Whether this server supports notifications for changes to the tool list.

SubscriptionFilter

Bases: WireModel

The set of notification types a client may opt in to on a {@link SubscriptionsListenRequestsubscriptions/listen} request.

Each notification type is opt-in; the server MUST NOT send notification types the client has not explicitly requested here.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SubscriptionFilter(WireModel):
    """
    The set of notification types a client may opt in to on a
    {@link SubscriptionsListenRequestsubscriptions/listen} request.

    Each notification type is **opt-in**; the server **MUST NOT** send
    notification types the client has not explicitly requested here.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    prompts_list_changed: Annotated[bool | None, Field(alias="promptsListChanged")] = None
    """
    If true, receive {@link PromptListChangedNotificationnotifications/prompts/list_changed}.
    """
    resource_subscriptions: Annotated[list[str] | None, Field(alias="resourceSubscriptions")] = None
    """
    Subscribe to {@link ResourceUpdatedNotificationnotifications/resources/updated} for these resource URIs.
    Replaces the former `resources/subscribe` RPC.
    """
    resources_list_changed: Annotated[bool | None, Field(alias="resourcesListChanged")] = None
    """
    If true, receive {@link ResourceListChangedNotificationnotifications/resources/list_changed}.
    """
    tools_list_changed: Annotated[bool | None, Field(alias="toolsListChanged")] = None
    """
    If true, receive {@link ToolListChangedNotificationnotifications/tools/list_changed}.
    """

prompts_list_changed class-attribute instance-attribute

prompts_list_changed: Annotated[
    bool | None, Field(alias="promptsListChanged")
] = None

If true, receive {@link PromptListChangedNotificationnotifications/prompts/list_changed}.

resource_subscriptions class-attribute instance-attribute

resource_subscriptions: Annotated[
    list[str] | None, Field(alias="resourceSubscriptions")
] = None

Subscribe to {@link ResourceUpdatedNotificationnotifications/resources/updated} for these resource URIs. Replaces the former resources/subscribe RPC.

resources_list_changed class-attribute instance-attribute

resources_list_changed: Annotated[
    bool | None, Field(alias="resourcesListChanged")
] = None

If true, receive {@link ResourceListChangedNotificationnotifications/resources/list_changed}.

tools_list_changed class-attribute instance-attribute

tools_list_changed: Annotated[
    bool | None, Field(alias="toolsListChanged")
] = None

If true, receive {@link ToolListChangedNotificationnotifications/tools/list_changed}.

TextResourceContents

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class TextResourceContents(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type of this resource, if known.
    """
    text: str
    """
    The text of the item. This must only be set if the item can actually be represented as text (not binary data).
    """
    uri: str
    """
    The URI of this resource.
    """

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type of this resource, if known.

text instance-attribute

text: str

The text of the item. This must only be set if the item can actually be represented as text (not binary data).

uri instance-attribute

uri: str

The URI of this resource.

AnyOfItem

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class AnyOfItem(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    const: str
    """
    The constant enum value.
    """
    title: str
    """
    Display title for this option.
    """

const instance-attribute

const: str

The constant enum value.

title instance-attribute

title: str

Display title for this option.

Items

Bases: WireModel

Schema for array items with enum options and display labels.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Items(WireModel):
    """
    Schema for array items with enum options and display labels.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    any_of: Annotated[list[AnyOfItem], Field(alias="anyOf")]
    """
    Array of enum options with values and display labels.
    """

any_of instance-attribute

any_of: Annotated[list[AnyOfItem], Field(alias='anyOf')]

Array of enum options with values and display labels.

TitledMultiSelectEnumSchema

Bases: WireModel

Schema for multiple-selection enumeration with display titles for each option.

Source code in src/mcp/types/v2026_07_28/__init__.py

class TitledMultiSelectEnumSchema(WireModel):
    """
    Schema for multiple-selection enumeration with display titles for each option.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    default: list[str] | None = None
    """
    Optional default value.
    """
    description: str | None = None
    """
    Optional description for the enum field.
    """
    items: Items
    """
    Schema for array items with enum options and display labels.
    """
    max_items: Annotated[int | None, Field(alias="maxItems")] = None
    """
    Maximum number of items to select.
    """
    min_items: Annotated[int | None, Field(alias="minItems")] = None
    """
    Minimum number of items to select.
    """
    title: str | None = None
    """
    Optional title for the enum field.
    """
    type: Literal["array"]

default class-attribute instance-attribute

default: list[str] | None = None

Optional default value.

description class-attribute instance-attribute

description: str | None = None

Optional description for the enum field.

items instance-attribute

items: Items

Schema for array items with enum options and display labels.

max_items class-attribute instance-attribute

max_items: Annotated[
    int | None, Field(alias="maxItems")
] = None

Maximum number of items to select.

min_items class-attribute instance-attribute

min_items: Annotated[
    int | None, Field(alias="minItems")
] = None

Minimum number of items to select.

title class-attribute instance-attribute

title: str | None = None

Optional title for the enum field.

OneOfItem

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class OneOfItem(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    const: str
    """
    The enum value.
    """
    title: str
    """
    Display label for this option.
    """

const instance-attribute

const: str

The enum value.

title instance-attribute

title: str

Display label for this option.

TitledSingleSelectEnumSchema

Bases: WireModel

Schema for single-selection enumeration with display titles for each option.

Source code in src/mcp/types/v2026_07_28/__init__.py

class TitledSingleSelectEnumSchema(WireModel):
    """
    Schema for single-selection enumeration with display titles for each option.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    default: str | None = None
    """
    Optional default value.
    """
    description: str | None = None
    """
    Optional description for the enum field.
    """
    one_of: Annotated[list[OneOfItem], Field(alias="oneOf")]
    """
    Array of enum options with values and display labels.
    """
    title: str | None = None
    """
    Optional title for the enum field.
    """
    type: Literal["string"]

default class-attribute instance-attribute

default: str | None = None

Optional default value.

description class-attribute instance-attribute

description: str | None = None

Optional description for the enum field.

one_of instance-attribute

one_of: Annotated[list[OneOfItem], Field(alias='oneOf')]

Array of enum options with values and display labels.

title class-attribute instance-attribute

title: str | None = None

Optional title for the enum field.

InputSchema

Bases: WireModel

A JSON Schema object defining the expected parameters for the tool.

Tool arguments are always JSON objects, so type: "object" is required at the root. Beyond that, any JSON Schema 2020-12 keyword may appear alongside type — including composition keywords (oneOf, anyOf, allOf, not), conditional keywords (if/then/else), reference keywords ($ref, $defs, $anchor), and any other standard validation or annotation keywords.

Property schemas may carry an x-mcp-header annotation to mirror the argument value into an HTTP header on the Streamable HTTP transport. See the Streamable HTTP transport specification for the validity and extraction rules.

Defaults to JSON Schema 2020-12 when no explicit $schema is provided.

Source code in src/mcp/types/v2026_07_28/__init__.py

class InputSchema(WireModel):
    """
    A JSON Schema object defining the expected parameters for the tool.

    Tool arguments are always JSON objects, so `type: "object"` is required at the root.
    Beyond that, any JSON Schema 2020-12 keyword may appear alongside `type` — including
    composition keywords (`oneOf`, `anyOf`, `allOf`, `not`), conditional keywords
    (`if`/`then`/`else`), reference keywords (`$ref`, `$defs`, `$anchor`), and any other
    standard validation or annotation keywords.

    Property schemas may carry an `x-mcp-header` annotation to mirror the
    argument value into an HTTP header on the Streamable HTTP transport. See
    the Streamable HTTP transport specification for the validity and
    extraction rules.

    Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
    """

    model_config = ConfigDict(
        extra="allow",
    )
    schema_: Annotated[str | None, Field(alias="$schema")] = None
    type: Literal["object"]

OutputSchema

Bases: WireModel

An optional JSON Schema object defining the structure of the tool's output returned in the structuredContent field of a {@link CallToolResult}. This can be any valid JSON Schema 2020-12.

Defaults to JSON Schema 2020-12 when no explicit $schema is provided.

Source code in src/mcp/types/v2026_07_28/__init__.py

class OutputSchema(WireModel):
    """
    An optional JSON Schema object defining the structure of the tool's output returned in
    the structuredContent field of a {@link CallToolResult}. This can be any valid JSON Schema 2020-12.

    Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
    """

    model_config = ConfigDict(
        extra="allow",
    )
    schema_: Annotated[str | None, Field(alias="$schema")] = None

ToolAnnotations

Bases: WireModel

Additional properties describing a {@link Tool} to clients.

NOTE: all properties in ToolAnnotations are hints. They are not guaranteed to provide a faithful description of tool behavior (including descriptive properties like title).

Clients should never make tool use decisions based on ToolAnnotations received from untrusted servers.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ToolAnnotations(WireModel):
    """
    Additional properties describing a {@link Tool} to clients.

    NOTE: all properties in `ToolAnnotations` are **hints**.
    They are not guaranteed to provide a faithful description of
    tool behavior (including descriptive properties like `title`).

    Clients should never make tool use decisions based on `ToolAnnotations`
    received from untrusted servers.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    destructive_hint: Annotated[bool | None, Field(alias="destructiveHint")] = None
    """
    If true, the tool may perform destructive updates to its environment.
    If false, the tool performs only additive updates.

    (This property is meaningful only when `readOnlyHint == false`)

    Default: true
    """
    idempotent_hint: Annotated[bool | None, Field(alias="idempotentHint")] = None
    """
    If true, calling the tool repeatedly with the same arguments
    will have no additional effect on its environment.

    (This property is meaningful only when `readOnlyHint == false`)

    Default: false
    """
    open_world_hint: Annotated[bool | None, Field(alias="openWorldHint")] = None
    """
    If true, this tool may interact with an "open world" of external
    entities. If false, the tool's domain of interaction is closed.
    For example, the world of a web search tool is open, whereas that
    of a memory tool is not.

    Default: true
    """
    read_only_hint: Annotated[bool | None, Field(alias="readOnlyHint")] = None
    """
    If true, the tool does not modify its environment.

    Default: false
    """
    title: str | None = None
    """
    A human-readable title for the tool.
    """

destructive_hint class-attribute instance-attribute

destructive_hint: Annotated[
    bool | None, Field(alias="destructiveHint")
] = None

If true, the tool may perform destructive updates to its environment. If false, the tool performs only additive updates.

(This property is meaningful only when readOnlyHint == false)

Default: true

idempotent_hint class-attribute instance-attribute

idempotent_hint: Annotated[
    bool | None, Field(alias="idempotentHint")
] = None

If true, calling the tool repeatedly with the same arguments will have no additional effect on its environment.

(This property is meaningful only when readOnlyHint == false)

Default: false

open_world_hint class-attribute instance-attribute

open_world_hint: Annotated[
    bool | None, Field(alias="openWorldHint")
] = None

If true, this tool may interact with an "open world" of external entities. If false, the tool's domain of interaction is closed. For example, the world of a web search tool is open, whereas that of a memory tool is not.

Default: true

read_only_hint class-attribute instance-attribute

read_only_hint: Annotated[
    bool | None, Field(alias="readOnlyHint")
] = None

If true, the tool does not modify its environment.

Default: false

title class-attribute instance-attribute

title: str | None = None

A human-readable title for the tool.

ToolChoice

Bases: WireModel

Controls tool selection behavior for sampling requests.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ToolChoice(WireModel):
    """
    Controls tool selection behavior for sampling requests.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    mode: Literal["auto", "none", "required"] | None = None
    """
    Controls the tool use ability of the model:
    - `"auto"`: Model decides whether to use tools (default)
    - `"required"`: Model MUST use at least one tool before completing
    - `"none"`: Model MUST NOT use any tools
    """

mode class-attribute instance-attribute

mode: Literal['auto', 'none', 'required'] | None = None

Controls the tool use ability of the model: - "auto": Model decides whether to use tools (default) - "required": Model MUST use at least one tool before completing - "none": Model MUST NOT use any tools

ToolUseContent

Bases: WireModel

A request from the assistant to call a tool.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ToolUseContent(WireModel):
    """
    A request from the assistant to call a tool.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    """
    Optional metadata about the tool use. Clients SHOULD preserve this field when
    including tool uses in subsequent sampling requests to enable caching optimizations.
    """
    id: str
    """
    A unique identifier for this tool use.

    This ID is used to match tool results to their corresponding tool uses.
    """
    input: dict[str, Any]
    """
    The arguments to pass to the tool, conforming to the tool's input schema.
    """
    name: str
    """
    The name of the tool to call.
    """
    type: Literal["tool_use"]

meta class-attribute instance-attribute

meta: Annotated[MetaObject | None, Field(alias="_meta")] = (
    None
)

Optional metadata about the tool use. Clients SHOULD preserve this field when including tool uses in subsequent sampling requests to enable caching optimizations.

id instance-attribute

id: str

A unique identifier for this tool use.

This ID is used to match tool results to their corresponding tool uses.

input instance-attribute

input: dict[str, Any]

The arguments to pass to the tool, conforming to the tool's input schema.

name instance-attribute

name: str

The name of the tool to call.

Data1

Bases: WireModel

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

Source code in src/mcp/types/v2026_07_28/__init__.py

class Data1(WireModel):
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    requested: str
    """
    The protocol version that was requested by the client.
    """
    supported: list[str]
    """
    Protocol versions the server supports. The client should choose a
    mutually supported version from this list and retry.
    """

requested instance-attribute

requested: str

The protocol version that was requested by the client.

supported instance-attribute

supported: list[str]

Protocol versions the server supports. The client should choose a mutually supported version from this list and retry.

Error3

Bases: Error

Source code in src/mcp/types/v2026_07_28/__init__.py

class Error3(Error):
    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32022]
    """
    The error type that occurred.
    """
    data: Data1
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """

code instance-attribute

code: Literal[-32022]

The error type that occurred.

data instance-attribute

data: Data1

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

UnsupportedProtocolVersionError

Bases: WireModel

Returned when the request's protocol version is unknown to the server or unsupported (e.g., a known experimental or draft version the server has chosen not to implement). For HTTP, the response status code MUST be 400 Bad Request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class UnsupportedProtocolVersionError(WireModel):
    """
    Returned when the request's protocol version is unknown to the server or
    unsupported (e.g., a known experimental or draft version the server has
    chosen not to implement). For HTTP, the response status code MUST be
    `400 Bad Request`.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    error: Error3
    id: RequestId | None = None
    jsonrpc: Literal["2.0"]

Items1

Bases: WireModel

Schema for the array items.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Items1(WireModel):
    """
    Schema for the array items.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    enum: list[str]
    """
    Array of enum values to choose from.
    """
    type: Literal["string"]

enum instance-attribute

enum: list[str]

Array of enum values to choose from.

UntitledMultiSelectEnumSchema

Bases: WireModel

Schema for multiple-selection enumeration without display titles for options.

Source code in src/mcp/types/v2026_07_28/__init__.py

class UntitledMultiSelectEnumSchema(WireModel):
    """
    Schema for multiple-selection enumeration without display titles for options.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    default: list[str] | None = None
    """
    Optional default value.
    """
    description: str | None = None
    """
    Optional description for the enum field.
    """
    items: Items1
    """
    Schema for the array items.
    """
    max_items: Annotated[int | None, Field(alias="maxItems")] = None
    """
    Maximum number of items to select.
    """
    min_items: Annotated[int | None, Field(alias="minItems")] = None
    """
    Minimum number of items to select.
    """
    title: str | None = None
    """
    Optional title for the enum field.
    """
    type: Literal["array"]

default class-attribute instance-attribute

default: list[str] | None = None

Optional default value.

description class-attribute instance-attribute

description: str | None = None

Optional description for the enum field.

items instance-attribute

items: Items1

Schema for the array items.

max_items class-attribute instance-attribute

max_items: Annotated[
    int | None, Field(alias="maxItems")
] = None

Maximum number of items to select.

min_items class-attribute instance-attribute

min_items: Annotated[
    int | None, Field(alias="minItems")
] = None

Minimum number of items to select.

title class-attribute instance-attribute

title: str | None = None

Optional title for the enum field.

UntitledSingleSelectEnumSchema

Bases: WireModel

Schema for single-selection enumeration without display titles for options.

Source code in src/mcp/types/v2026_07_28/__init__.py

class UntitledSingleSelectEnumSchema(WireModel):
    """
    Schema for single-selection enumeration without display titles for options.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    default: str | None = None
    """
    Optional default value.
    """
    description: str | None = None
    """
    Optional description for the enum field.
    """
    enum: list[str]
    """
    Array of enum values to choose from.
    """
    title: str | None = None
    """
    Optional title for the enum field.
    """
    type: Literal["string"]

default class-attribute instance-attribute

default: str | None = None

Optional default value.

description class-attribute instance-attribute

description: str | None = None

Optional description for the enum field.

enum instance-attribute

enum: list[str]

Array of enum values to choose from.

title class-attribute instance-attribute

title: str | None = None

Optional title for the enum field.

Annotations

Bases: WireModel

Optional annotations for the client. The client can use annotations to inform how objects are used or displayed

Source code in src/mcp/types/v2026_07_28/__init__.py

class Annotations(WireModel):
    """
    Optional annotations for the client. The client can use annotations to inform how objects are used or displayed
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    audience: list[Role] | None = None
    """
    Describes who the intended audience of this object or data is.

    It can include multiple entries to indicate content useful for multiple audiences (e.g., `["user", "assistant"]`).
    """
    last_modified: Annotated[str | None, Field(alias="lastModified")] = None
    """
    The moment the resource was last modified, as an ISO 8601 formatted string.

    Should be an ISO 8601 formatted string (e.g., "2025-01-12T15:00:58Z").

    Examples: last activity timestamp in an open file, timestamp when the resource
    was attached, etc.
    """
    priority: Annotated[float | None, Field(ge=0.0, le=1.0)] = None
    """
    Describes how important this data is for operating the server.

    A value of 1 means "most important," and indicates that the data is
    effectively required, while 0 means "least important," and indicates that
    the data is entirely optional.
    """

audience class-attribute instance-attribute

audience: list[Role] | None = None

Describes who the intended audience of this object or data is.

It can include multiple entries to indicate content useful for multiple audiences (e.g., ["user", "assistant"]).

last_modified class-attribute instance-attribute

last_modified: Annotated[
    str | None, Field(alias="lastModified")
] = None

The moment the resource was last modified, as an ISO 8601 formatted string.

Should be an ISO 8601 formatted string (e.g., "2025-01-12T15:00:58Z").

Examples: last activity timestamp in an open file, timestamp when the resource was attached, etc.

priority class-attribute instance-attribute

priority: Annotated[float | None, Field(ge=0.0, le=1.0)] = (
    None
)

Describes how important this data is for operating the server.

A value of 1 means "most important," and indicates that the data is effectively required, while 0 means "least important," and indicates that the data is entirely optional.

AudioContent

Bases: WireModel

Audio provided to or from an LLM.

Source code in src/mcp/types/v2026_07_28/__init__.py

class AudioContent(WireModel):
    """
    Audio provided to or from an LLM.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    data: str
    """
    The base64-encoded audio data.
    """
    mime_type: Annotated[str, Field(alias="mimeType")]
    """
    The MIME type of the audio. Different providers may support different audio types.
    """
    type: Literal["audio"]

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

data instance-attribute

data: str

The base64-encoded audio data.

mime_type instance-attribute

mime_type: Annotated[str, Field(alias='mimeType')]

The MIME type of the audio. Different providers may support different audio types.

BlobResourceContents

Bases: WireModel

Source code in src/mcp/types/v2026_07_28/__init__.py

class BlobResourceContents(WireModel):
    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    blob: str
    """
    A base64-encoded string representing the binary data of the item.
    """
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type of this resource, if known.
    """
    uri: str
    """
    The URI of this resource.
    """

blob instance-attribute

blob: str

A base64-encoded string representing the binary data of the item.

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type of this resource, if known.

uri instance-attribute

uri: str

The URI of this resource.

CacheableResult

Bases: WireModel

A result that supports a time-to-live (TTL) hint for client-side caching.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CacheableResult(WireModel):
    """
    A result that supports a time-to-live (TTL) hint for client-side caching.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

ClientResult

Bases: RootModel[Result]

Source code in src/mcp/types/v2026_07_28/__init__.py

class ClientResult(RootModel[Result]):
    root: Result
    """
    Common result fields.
    """

root instance-attribute

root: Result

Common result fields.

CompleteResult

Bases: WireModel

The result returned by the server for a {@link CompleteRequestcompletion/complete} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CompleteResult(WireModel):
    """
    The result returned by the server for a {@link CompleteRequestcompletion/complete} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    completion: Completion
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

CompleteResultResponse

Bases: WireModel

A successful response from the server for a {@link CompleteRequestcompletion/complete} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CompleteResultResponse(WireModel):
    """
    A successful response from the server for a {@link CompleteRequestcompletion/complete} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: CompleteResult

ElicitRequestParams

Bases: RootModel[ElicitRequestFormParams | ElicitRequestURLParams]

Source code in src/mcp/types/v2026_07_28/__init__.py

class ElicitRequestParams(RootModel[ElicitRequestFormParams | ElicitRequestURLParams]):
    root: ElicitRequestFormParams | ElicitRequestURLParams
    """
    The parameters for a request to elicit additional information from the user via the client.
    """

root instance-attribute

root: ElicitRequestFormParams | ElicitRequestURLParams

The parameters for a request to elicit additional information from the user via the client.

EmbeddedResource

Bases: WireModel

The contents of a resource, embedded into a prompt or tool call result.

It is up to the client how best to render embedded resources for the benefit of the LLM and/or the user.

Source code in src/mcp/types/v2026_07_28/__init__.py

class EmbeddedResource(WireModel):
    """
    The contents of a resource, embedded into a prompt or tool call result.

    It is up to the client how best to render embedded resources for the benefit
    of the LLM and/or the user.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    resource: TextResourceContents | BlobResourceContents
    type: Literal["resource"]

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

EmptyResult

Bases: RootModel[Result]

Source code in src/mcp/types/v2026_07_28/__init__.py

class EmptyResult(RootModel[Result]):
    root: Result
    """
    Common result fields.
    """

root instance-attribute

root: Result

Common result fields.

HeaderMismatchError

Bases: WireModel

Returned when a server rejects a request because the values in the HTTP headers do not match the corresponding values in the request body, or because required headers are missing or malformed. For HTTP, the response status code MUST be 400 Bad Request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class HeaderMismatchError(WireModel):
    """
    Returned when a server rejects a request because the values in the HTTP
    headers do not match the corresponding values in the request body, or
    because required headers are missing or malformed. For HTTP, the response
    status code MUST be `400 Bad Request`.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    error: Error1
    id: RequestId | None = None
    jsonrpc: Literal["2.0"]

ImageContent

Bases: WireModel

An image provided to or from an LLM.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ImageContent(WireModel):
    """
    An image provided to or from an LLM.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    data: str
    """
    The base64-encoded image data.
    """
    mime_type: Annotated[str, Field(alias="mimeType")]
    """
    The MIME type of the image. Different providers may support different image types.
    """
    type: Literal["image"]

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

data instance-attribute

data: str

The base64-encoded image data.

mime_type instance-attribute

mime_type: Annotated[str, Field(alias='mimeType')]

The MIME type of the image. Different providers may support different image types.

JSONRPCErrorResponse

Bases: WireModel

A response to a request that indicates an error occurred.

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCErrorResponse(WireModel):
    """
    A response to a request that indicates an error occurred.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    error: Error
    id: RequestId | None = None
    jsonrpc: Literal["2.0"]

JSONRPCRequest

Bases: WireModel

A request that expects a response.

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCRequest(WireModel):
    """
    A request that expects a response.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: str
    params: dict[str, Any] | None = None

JSONRPCResultResponse

Bases: WireModel

A successful (non-error) response to a request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCResultResponse(WireModel):
    """
    A successful (non-error) response to a request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: Result

ListRootsRequest

Bases: WireModel

Sent from the server to request a list of root URIs from the client. Roots allow servers to ask for specific directories or files to operate on. A common example for roots is providing a set of repositories or directories a server should operate on.

This request is typically used when the server needs to understand the file system structure or access specific locations that the client has permission to read from.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListRootsRequest(WireModel):
    """
    Sent from the server to request a list of root URIs from the client. Roots allow
    servers to ask for specific directories or files to operate on. A common example
    for roots is providing a set of repositories or directories a server should operate
    on.

    This request is typically used when the server needs to understand the file system
    structure or access specific locations that the client has permission to read from.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    method: Literal["roots/list"]
    params: Params | None = None

ListRootsResult

Bases: WireModel

The result returned by the client for a {@link ListRootsRequestroots/list} request. This result contains an array of {@link Root} objects, each representing a root directory or file that the server can operate on.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListRootsResult(WireModel):
    """
    The result returned by the client for a {@link ListRootsRequestroots/list} request.
    This result contains an array of {@link Root} objects, each representing a root directory
    or file that the server can operate on.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    roots: list[Root]

NotificationMetaObject

Bases: WireModel

Extends {@link MetaObject} with additional notification-specific fields. All key naming rules from MetaObject apply.

Source code in src/mcp/types/v2026_07_28/__init__.py

class NotificationMetaObject(WireModel):
    """
    Extends {@link MetaObject} with additional notification-specific fields. All key naming rules from `MetaObject` apply.
    """

    model_config = ConfigDict(
        extra="allow",
    )
    io_modelcontextprotocol_subscription_id: Annotated[
        RequestId | None, Field(alias="io.modelcontextprotocol/subscriptionId")
    ] = None
    """
    Identifies the subscription stream a notification was delivered on. The
    server MUST include this key on every notification delivered via a
    {@link SubscriptionsListenRequestsubscriptions/listen} stream, so the
    client can correlate the notification with the originating subscription.
    The key is absent on notifications not delivered via a subscription
    stream (e.g. progress notifications for an in-flight request), which is
    why it is optional here.

    The value is the JSON-RPC ID of the `subscriptions/listen` request that
    opened the stream.
    """

io_modelcontextprotocol_subscription_id class-attribute instance-attribute

io_modelcontextprotocol_subscription_id: Annotated[
    RequestId | None,
    Field(alias="io.modelcontextprotocol/subscriptionId"),
] = None

Identifies the subscription stream a notification was delivered on. The server MUST include this key on every notification delivered via a {@link SubscriptionsListenRequestsubscriptions/listen} stream, so the client can correlate the notification with the originating subscription. The key is absent on notifications not delivered via a subscription stream (e.g. progress notifications for an in-flight request), which is why it is optional here.

The value is the JSON-RPC ID of the subscriptions/listen request that opened the stream.

NotificationParams

Bases: WireModel

Common params for any notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class NotificationParams(WireModel):
    """
    Common params for any notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None

PrimitiveSchemaDefinition

Bases: RootModel[StringSchema | NumberSchema | BooleanSchema | UntitledSingleSelectEnumSchema | TitledSingleSelectEnumSchema | UntitledMultiSelectEnumSchema | TitledMultiSelectEnumSchema | LegacyTitledEnumSchema]

Source code in src/mcp/types/v2026_07_28/__init__.py

class PrimitiveSchemaDefinition(
    RootModel[
        StringSchema
        | NumberSchema
        | BooleanSchema
        | UntitledSingleSelectEnumSchema
        | TitledSingleSelectEnumSchema
        | UntitledMultiSelectEnumSchema
        | TitledMultiSelectEnumSchema
        | LegacyTitledEnumSchema
    ]
):
    root: (
        StringSchema
        | NumberSchema
        | BooleanSchema
        | UntitledSingleSelectEnumSchema
        | TitledSingleSelectEnumSchema
        | UntitledMultiSelectEnumSchema
        | TitledMultiSelectEnumSchema
        | LegacyTitledEnumSchema
    )
    """
    Restricted schema definitions that only allow primitive types
    without nested objects or arrays.
    """

root instance-attribute

root: (
    StringSchema
    | NumberSchema
    | BooleanSchema
    | UntitledSingleSelectEnumSchema
    | TitledSingleSelectEnumSchema
    | UntitledMultiSelectEnumSchema
    | TitledMultiSelectEnumSchema
    | LegacyTitledEnumSchema
)

Restricted schema definitions that only allow primitive types without nested objects or arrays.

ProgressNotificationParams

Bases: WireModel

Parameters for a {@link ProgressNotificationnotifications/progress} notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ProgressNotificationParams(WireModel):
    """
    Parameters for a {@link ProgressNotificationnotifications/progress} notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None
    message: str | None = None
    """
    An optional message describing the current progress.
    """
    progress: float
    """
    The progress thus far. This should increase every time progress is made, even if the total is unknown.
    """
    progress_token: Annotated[ProgressToken, Field(alias="progressToken")]
    """
    The progress token which was given in the initial request, used to associate this notification with the request that is proceeding.
    """
    total: float | None = None
    """
    Total number of items to process (or total progress required), if known.
    """

message class-attribute instance-attribute

message: str | None = None

An optional message describing the current progress.

progress instance-attribute

progress: float

The progress thus far. This should increase every time progress is made, even if the total is unknown.

progress_token instance-attribute

progress_token: Annotated[
    ProgressToken, Field(alias="progressToken")
]

The progress token which was given in the initial request, used to associate this notification with the request that is proceeding.

total class-attribute instance-attribute

total: float | None = None

Total number of items to process (or total progress required), if known.

Prompt

Bases: WireModel

A prompt or prompt template that the server offers.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Prompt(WireModel):
    """
    A prompt or prompt template that the server offers.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    arguments: list[PromptArgument] | None = None
    """
    A list of arguments to use for templating the prompt.
    """
    description: str | None = None
    """
    An optional description of what this prompt provides
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """

arguments class-attribute instance-attribute

arguments: list[PromptArgument] | None = None

A list of arguments to use for templating the prompt.

description class-attribute instance-attribute

description: str | None = None

An optional description of what this prompt provides

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

PromptListChangedNotification

Bases: WireModel

An optional notification from the server to the client, informing it that the list of prompts it offers has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the promptsListChanged filter field.

Source code in src/mcp/types/v2026_07_28/__init__.py

class PromptListChangedNotification(WireModel):
    """
    An optional notification from the server to the client, informing it that the list of prompts it offers has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the `promptsListChanged` filter field.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/prompts/list_changed"]
    params: NotificationParams | None = None

ReadResourceResult

Bases: WireModel

The result returned by the server for a {@link ReadResourceRequestresources/read} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ReadResourceResult(WireModel):
    """
    The result returned by the server for a {@link ReadResourceRequestresources/read} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    contents: list[TextResourceContents | BlobResourceContents]
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

Resource

Bases: WireModel

A known resource that the server is capable of reading.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Resource(WireModel):
    """
    A known resource that the server is capable of reading.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    description: str | None = None
    """
    A description of what this resource represents.

    This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type of this resource, if known.
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    size: int | None = None
    """
    The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

    This can be used by Hosts to display file sizes and estimate context window usage.
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """
    uri: str
    """
    The URI of this resource.
    """

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

description class-attribute instance-attribute

description: str | None = None

A description of what this resource represents.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type of this resource, if known.

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

size class-attribute instance-attribute

size: int | None = None

The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

This can be used by Hosts to display file sizes and estimate context window usage.

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

uri instance-attribute

uri: str

The URI of this resource.

ResourceLink

Bases: WireModel

A resource that the server is capable of reading, included in a prompt or tool call result.

Note: resource links returned by tools are not guaranteed to appear in the results of {@link ListResourcesRequestresources/list} requests.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceLink(WireModel):
    """
    A resource that the server is capable of reading, included in a prompt or tool call result.

    Note: resource links returned by tools are not guaranteed to appear in the results of {@link ListResourcesRequestresources/list} requests.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    description: str | None = None
    """
    A description of what this resource represents.

    This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type of this resource, if known.
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    size: int | None = None
    """
    The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

    This can be used by Hosts to display file sizes and estimate context window usage.
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """
    type: Literal["resource_link"]
    uri: str
    """
    The URI of this resource.
    """

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

description class-attribute instance-attribute

description: str | None = None

A description of what this resource represents.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type of this resource, if known.

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

size class-attribute instance-attribute

size: int | None = None

The size of the raw resource content, in bytes (i.e., before base64 encoding or any tokenization), if known.

This can be used by Hosts to display file sizes and estimate context window usage.

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

uri instance-attribute

uri: str

The URI of this resource.

ResourceListChangedNotification

Bases: WireModel

An optional notification from the server to the client, informing it that the list of resources it can read from has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the resourcesListChanged filter field.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceListChangedNotification(WireModel):
    """
    An optional notification from the server to the client, informing it that the list of resources it can read from has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the `resourcesListChanged` filter field.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/resources/list_changed"]
    params: NotificationParams | None = None

ResourceTemplate

Bases: WireModel

A template description for resources available on the server.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceTemplate(WireModel):
    """
    A template description for resources available on the server.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    description: str | None = None
    """
    A description of what this template is for.

    This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    mime_type: Annotated[str | None, Field(alias="mimeType")] = None
    """
    The MIME type for all resources that match this template. This should only be included if all resources matching this template have the same type.
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """
    uri_template: Annotated[str, Field(alias="uriTemplate")]
    """
    A URI template (according to RFC 6570) that can be used to construct resource URIs.
    """

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

description class-attribute instance-attribute

description: str | None = None

A description of what this template is for.

This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a "hint" to the model.

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

mime_type class-attribute instance-attribute

mime_type: Annotated[
    str | None, Field(alias="mimeType")
] = None

The MIME type for all resources that match this template. This should only be included if all resources matching this template have the same type.

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

uri_template instance-attribute

uri_template: Annotated[str, Field(alias='uriTemplate')]

A URI template (according to RFC 6570) that can be used to construct resource URIs.

ResourceUpdatedNotificationParams

Bases: WireModel

Parameters for a notifications/resources/updated notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceUpdatedNotificationParams(WireModel):
    """
    Parameters for a `notifications/resources/updated` notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None
    uri: str
    """
    The URI of the resource that has been updated. This might be a sub-resource of the one that the client actually subscribed to.
    """

uri instance-attribute

uri: str

The URI of the resource that has been updated. This might be a sub-resource of the one that the client actually subscribed to.

SubscriptionsAcknowledgedNotificationParams

Bases: WireModel

Parameters for a {@link SubscriptionsAcknowledgedNotificationnotifications/subscriptions/acknowledged} notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SubscriptionsAcknowledgedNotificationParams(WireModel):
    """
    Parameters for a {@link SubscriptionsAcknowledgedNotificationnotifications/subscriptions/acknowledged} notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None
    notifications: SubscriptionFilter
    """
    The subset of requested notification types the server agreed to honor.
    Only includes notification types the server actually supports; if the
    client requested an unsupported type (e.g., `promptsListChanged` when
    the server has no prompts), it is omitted from this set.
    """

notifications instance-attribute

notifications: SubscriptionFilter

The subset of requested notification types the server agreed to honor. Only includes notification types the server actually supports; if the client requested an unsupported type (e.g., promptsListChanged when the server has no prompts), it is omitted from this set.

TextContent

Bases: WireModel

Text provided to or from an LLM.

Source code in src/mcp/types/v2026_07_28/__init__.py

class TextContent(WireModel):
    """
    Text provided to or from an LLM.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: Annotations | None = None
    """
    Optional annotations for the client.
    """
    text: str
    """
    The text content of the message.
    """
    type: Literal["text"]

annotations class-attribute instance-attribute

annotations: Annotations | None = None

Optional annotations for the client.

text instance-attribute

text: str

The text content of the message.

Tool

Bases: WireModel

Definition for a tool the client can call.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Tool(WireModel):
    """
    Definition for a tool the client can call.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    annotations: ToolAnnotations | None = None
    """
    Optional additional tool information.

    Display name precedence order is: `title`, `annotations.title`, then `name`.
    """
    description: str | None = None
    """
    A human-readable description of the tool.

    This can be used by clients to improve the LLM's understanding of available tools. It can be thought of like a "hint" to the model.
    """
    icons: list[Icon] | None = None
    """
    Optional set of sized icons that the client can display in a user interface.

    Clients that support rendering icons MUST support at least the following MIME types:
    - `image/png` - PNG images (safe, universal compatibility)
    - `image/jpeg` (and `image/jpg`) - JPEG images (safe, universal compatibility)

    Clients that support rendering icons SHOULD also support:
    - `image/svg+xml` - SVG images (scalable but requires security precautions)
    - `image/webp` - WebP images (modern, efficient format)
    """
    input_schema: Annotated[InputSchema, Field(alias="inputSchema")]
    """
    A JSON Schema object defining the expected parameters for the tool.

    Tool arguments are always JSON objects, so `type: "object"` is required at the root.
    Beyond that, any JSON Schema 2020-12 keyword may appear alongside `type` — including
    composition keywords (`oneOf`, `anyOf`, `allOf`, `not`), conditional keywords
    (`if`/`then`/`else`), reference keywords (`$ref`, `$defs`, `$anchor`), and any other
    standard validation or annotation keywords.

    Property schemas may carry an `x-mcp-header` annotation to mirror the
    argument value into an HTTP header on the Streamable HTTP transport. See
    the Streamable HTTP transport specification for the validity and
    extraction rules.

    Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
    """
    name: str
    """
    Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).
    """
    output_schema: Annotated[OutputSchema | None, Field(alias="outputSchema")] = None
    """
    An optional JSON Schema object defining the structure of the tool's output returned in
    the structuredContent field of a {@link CallToolResult}. This can be any valid JSON Schema 2020-12.

    Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
    """
    title: str | None = None
    """
    Intended for UI and end-user contexts — optimized to be human-readable and easily understood,
    even by those unfamiliar with domain-specific terminology.

    If not provided, the name should be used for display (except for {@link Tool},
    where `annotations.title` should be given precedence over using `name`,
    if present).
    """

annotations class-attribute instance-attribute

annotations: ToolAnnotations | None = None

Optional additional tool information.

Display name precedence order is: title, annotations.title, then name.

description class-attribute instance-attribute

description: str | None = None

A human-readable description of the tool.

This can be used by clients to improve the LLM's understanding of available tools. It can be thought of like a "hint" to the model.

icons class-attribute instance-attribute

icons: list[Icon] | None = None

Optional set of sized icons that the client can display in a user interface.

Clients that support rendering icons MUST support at least the following MIME types: - image/png - PNG images (safe, universal compatibility) - image/jpeg (and image/jpg) - JPEG images (safe, universal compatibility)

Clients that support rendering icons SHOULD also support: - image/svg+xml - SVG images (scalable but requires security precautions) - image/webp - WebP images (modern, efficient format)

input_schema instance-attribute

input_schema: Annotated[
    InputSchema, Field(alias="inputSchema")
]

A JSON Schema object defining the expected parameters for the tool.

Tool arguments are always JSON objects, so type: "object" is required at the root. Beyond that, any JSON Schema 2020-12 keyword may appear alongside type — including composition keywords (oneOf, anyOf, allOf, not), conditional keywords (if/then/else), reference keywords ($ref, $defs, $anchor), and any other standard validation or annotation keywords.

Property schemas may carry an x-mcp-header annotation to mirror the argument value into an HTTP header on the Streamable HTTP transport. See the Streamable HTTP transport specification for the validity and extraction rules.

Defaults to JSON Schema 2020-12 when no explicit $schema is provided.

name instance-attribute

name: str

Intended for programmatic or logical use, but used as a display name in past specs or fallback (if title isn't present).

output_schema class-attribute instance-attribute

output_schema: Annotated[
    OutputSchema | None, Field(alias="outputSchema")
] = None

An optional JSON Schema object defining the structure of the tool's output returned in the structuredContent field of a {@link CallToolResult}. This can be any valid JSON Schema 2020-12.

Defaults to JSON Schema 2020-12 when no explicit $schema is provided.

title class-attribute instance-attribute

title: str | None = None

Intended for UI and end-user contexts — optimized to be human-readable and easily understood, even by those unfamiliar with domain-specific terminology.

If not provided, the name should be used for display (except for {@link Tool}, where annotations.title should be given precedence over using name, if present).

ToolListChangedNotification

Bases: WireModel

An optional notification from the server to the client, informing it that the list of tools it offers has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the toolsListChanged filter field.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ToolListChangedNotification(WireModel):
    """
    An optional notification from the server to the client, informing it that the list of tools it offers has changed. This is only delivered on a {@link SubscriptionsListenRequestsubscriptions/listen} stream when the client requested it via the `toolsListChanged` filter field.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/tools/list_changed"]
    params: NotificationParams | None = None

CancelledNotificationParams

Bases: WireModel

Parameters for a notifications/cancelled notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CancelledNotificationParams(WireModel):
    """
    Parameters for a `notifications/cancelled` notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None
    reason: str | None = None
    """
    An optional string describing the reason for the cancellation. This MAY be logged or presented to the user.
    """
    request_id: Annotated[RequestId, Field(alias="requestId")]
    """
    The ID of the request to cancel.

    This MUST correspond to the ID of a request the client previously issued.
    """

reason class-attribute instance-attribute

reason: str | None = None

An optional string describing the reason for the cancellation. This MAY be logged or presented to the user.

request_id instance-attribute

request_id: Annotated[RequestId, Field(alias='requestId')]

The ID of the request to cancel.

This MUST correspond to the ID of a request the client previously issued.

ClientNotification

Bases: WireModel

This notification is sent by the client to indicate that it is cancelling a request it previously issued.

On stdio, the server also sends this notification, solely to terminate a {@link SubscriptionsListenRequestsubscriptions/listen} stream: it references the ID of the subscriptions/listen request that opened the stream. Servers MUST NOT use this notification to cancel any other request.

The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.

This notification indicates that the result will be unused, so any associated processing SHOULD cease.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ClientNotification(WireModel):
    """
    This notification is sent by the client to indicate that it is cancelling a request it previously issued.

    On stdio, the server also sends this notification, solely to terminate a {@link SubscriptionsListenRequestsubscriptions/listen} stream: it references the ID of the `subscriptions/listen` request that opened the stream. Servers MUST NOT use this notification to cancel any other request.

    The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.

    This notification indicates that the result will be unused, so any associated processing SHOULD cease.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/cancelled"]
    params: CancelledNotificationParams

ElicitRequest

Bases: WireModel

A request from the server to elicit additional information from the user via the client.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ElicitRequest(WireModel):
    """
    A request from the server to elicit additional information from the user via the client.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    method: Literal["elicitation/create"]
    params: ElicitRequestParams

JSONRPCMessage

Bases: RootModel[JSONRPCRequest | JSONRPCNotification | JSONRPCResultResponse | JSONRPCErrorResponse]

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCMessage(RootModel[JSONRPCRequest | JSONRPCNotification | JSONRPCResultResponse | JSONRPCErrorResponse]):
    root: JSONRPCRequest | JSONRPCNotification | JSONRPCResultResponse | JSONRPCErrorResponse
    """
    Refers to any valid JSON-RPC object that can be decoded off the wire, or encoded to be sent.
    """

root instance-attribute

root: (
    JSONRPCRequest
    | JSONRPCNotification
    | JSONRPCResultResponse
    | JSONRPCErrorResponse
)

Refers to any valid JSON-RPC object that can be decoded off the wire, or encoded to be sent.

JSONRPCResponse

Bases: RootModel[JSONRPCResultResponse | JSONRPCErrorResponse]

Source code in src/mcp/types/v2026_07_28/__init__.py

class JSONRPCResponse(RootModel[JSONRPCResultResponse | JSONRPCErrorResponse]):
    root: JSONRPCResultResponse | JSONRPCErrorResponse
    """
    A response to a request, containing either the result or error.
    """

root instance-attribute

root: JSONRPCResultResponse | JSONRPCErrorResponse

A response to a request, containing either the result or error.

ListPromptsResult

Bases: WireModel

The result returned by the server for a {@link ListPromptsRequestprompts/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListPromptsResult(WireModel):
    """
    The result returned by the server for a {@link ListPromptsRequestprompts/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    next_cursor: Annotated[str | None, Field(alias="nextCursor")] = None
    """
    An opaque token representing the pagination position after the last returned result.
    If present, there may be more results available.
    """
    prompts: list[Prompt]
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

next_cursor class-attribute instance-attribute

next_cursor: Annotated[
    str | None, Field(alias="nextCursor")
] = None

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

ListPromptsResultResponse

Bases: WireModel

A successful response from the server for a {@link ListPromptsRequestprompts/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListPromptsResultResponse(WireModel):
    """
    A successful response from the server for a {@link ListPromptsRequestprompts/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: ListPromptsResult

ListResourceTemplatesResult

Bases: WireModel

The result returned by the server for a {@link ListResourceTemplatesRequestresources/templates/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourceTemplatesResult(WireModel):
    """
    The result returned by the server for a {@link ListResourceTemplatesRequestresources/templates/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    next_cursor: Annotated[str | None, Field(alias="nextCursor")] = None
    """
    An opaque token representing the pagination position after the last returned result.
    If present, there may be more results available.
    """
    resource_templates: Annotated[list[ResourceTemplate], Field(alias="resourceTemplates")]
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

next_cursor class-attribute instance-attribute

next_cursor: Annotated[
    str | None, Field(alias="nextCursor")
] = None

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

ListResourceTemplatesResultResponse

Bases: WireModel

A successful response from the server for a {@link ListResourceTemplatesRequestresources/templates/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourceTemplatesResultResponse(WireModel):
    """
    A successful response from the server for a {@link ListResourceTemplatesRequestresources/templates/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: ListResourceTemplatesResult

ListResourcesResult

Bases: WireModel

The result returned by the server for a {@link ListResourcesRequestresources/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourcesResult(WireModel):
    """
    The result returned by the server for a {@link ListResourcesRequestresources/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    next_cursor: Annotated[str | None, Field(alias="nextCursor")] = None
    """
    An opaque token representing the pagination position after the last returned result.
    If present, there may be more results available.
    """
    resources: list[Resource]
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

next_cursor class-attribute instance-attribute

next_cursor: Annotated[
    str | None, Field(alias="nextCursor")
] = None

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

ListResourcesResultResponse

Bases: WireModel

A successful response from the server for a {@link ListResourcesRequestresources/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourcesResultResponse(WireModel):
    """
    A successful response from the server for a {@link ListResourcesRequestresources/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: ListResourcesResult

ListToolsResult

Bases: WireModel

The result returned by the server for a {@link ListToolsRequesttools/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListToolsResult(WireModel):
    """
    The result returned by the server for a {@link ListToolsRequesttools/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    next_cursor: Annotated[str | None, Field(alias="nextCursor")] = None
    """
    An opaque token representing the pagination position after the last returned result.
    If present, there may be more results available.
    """
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    tools: list[Tool]
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

next_cursor class-attribute instance-attribute

next_cursor: Annotated[
    str | None, Field(alias="nextCursor")
] = None

An opaque token representing the pagination position after the last returned result. If present, there may be more results available.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

ListToolsResultResponse

Bases: WireModel

A successful response from the server for a {@link ListToolsRequesttools/list} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListToolsResultResponse(WireModel):
    """
    A successful response from the server for a {@link ListToolsRequesttools/list} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: ListToolsResult

LoggingMessageNotificationParams

Bases: WireModel

Parameters for a notifications/message notification.

Source code in src/mcp/types/v2026_07_28/__init__.py

class LoggingMessageNotificationParams(WireModel):
    """
    Parameters for a `notifications/message` notification.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[NotificationMetaObject | None, Field(alias="_meta")] = None
    data: Any
    """
    The data to be logged, such as a string message or an object. Any JSON serializable type is allowed here.
    """
    level: LoggingLevel
    """
    The severity of this log message.
    """
    logger: str | None = None
    """
    An optional name of the logger issuing this message.
    """

data instance-attribute

data: Any

The data to be logged, such as a string message or an object. Any JSON serializable type is allowed here.

level instance-attribute

level: LoggingLevel

The severity of this log message.

logger class-attribute instance-attribute

logger: str | None = None

An optional name of the logger issuing this message.

ProgressNotification

Bases: WireModel

An out-of-band notification used to inform the receiver of a progress update for a long-running request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ProgressNotification(WireModel):
    """
    An out-of-band notification used to inform the receiver of a progress update for a long-running request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/progress"]
    params: ProgressNotificationParams

PromptMessage

Bases: WireModel

Describes a message returned as part of a prompt.

This is similar to {@link SamplingMessage}, but also supports the embedding of resources from the MCP server.

Source code in src/mcp/types/v2026_07_28/__init__.py

class PromptMessage(WireModel):
    """
    Describes a message returned as part of a prompt.

    This is similar to {@link SamplingMessage}, but also supports the embedding of
    resources from the MCP server.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    content: ContentBlock
    role: Role

ResourceUpdatedNotification

Bases: WireModel

A notification from the server to the client, informing it that a resource has changed and may need to be read again. This is only sent for resources the client opted in to via the resourceSubscriptions field of a {@link SubscriptionsListenRequestsubscriptions/listen} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceUpdatedNotification(WireModel):
    """
    A notification from the server to the client, informing it that a resource has changed and may need to be read again. This is only sent for resources the client opted in to via the `resourceSubscriptions` field of a {@link SubscriptionsListenRequestsubscriptions/listen} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/resources/updated"]
    params: ResourceUpdatedNotificationParams

SubscriptionsAcknowledgedNotification

Bases: WireModel

Sent by the server as the first message on a {@link SubscriptionsListenRequestsubscriptions/listen} stream to acknowledge that the subscription has been established and to report which notification types it agreed to honor.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SubscriptionsAcknowledgedNotification(WireModel):
    """
    Sent by the server as the first message on a
    {@link SubscriptionsListenRequestsubscriptions/listen} stream to acknowledge
    that the subscription has been established and to report which notification
    types it agreed to honor.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/subscriptions/acknowledged"]
    params: SubscriptionsAcknowledgedNotificationParams

ToolResultContent

Bases: WireModel

The result of a tool use, provided by the user back to the assistant.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ToolResultContent(WireModel):
    """
    The result of a tool use, provided by the user back to the assistant.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    """
    Optional metadata about the tool result. Clients SHOULD preserve this field when
    including tool results in subsequent sampling requests to enable caching optimizations.
    """
    content: list[ContentBlock]
    """
    The unstructured result content of the tool use.

    This has the same format as {@link CallToolResult.content} and can include text, images,
    audio, resource links, and embedded resources.
    """
    is_error: Annotated[bool | None, Field(alias="isError")] = None
    """
    Whether the tool use resulted in an error.

    If true, the content typically describes the error that occurred.
    Default: false
    """
    structured_content: Annotated[Any | None, Field(alias="structuredContent")] = None
    """
    An optional structured result value.

    This can be any JSON value (object, array, string, number, boolean, or null).
    If the tool defined an {@link Tool.outputSchema}, this SHOULD conform to that schema.
    """
    tool_use_id: Annotated[str, Field(alias="toolUseId")]
    """
    The ID of the tool use this result corresponds to.

    This MUST match the ID from a previous {@link ToolUseContent}.
    """
    type: Literal["tool_result"]

meta class-attribute instance-attribute

meta: Annotated[MetaObject | None, Field(alias="_meta")] = (
    None
)

Optional metadata about the tool result. Clients SHOULD preserve this field when including tool results in subsequent sampling requests to enable caching optimizations.

content instance-attribute

content: list[ContentBlock]

The unstructured result content of the tool use.

This has the same format as {@link CallToolResult.content} and can include text, images, audio, resource links, and embedded resources.

is_error class-attribute instance-attribute

is_error: Annotated[bool | None, Field(alias="isError")] = (
    None
)

Whether the tool use resulted in an error.

If true, the content typically describes the error that occurred. Default: false

structured_content class-attribute instance-attribute

structured_content: Annotated[
    Any | None, Field(alias="structuredContent")
] = None

An optional structured result value.

This can be any JSON value (object, array, string, number, boolean, or null). If the tool defined an {@link Tool.outputSchema}, this SHOULD conform to that schema.

tool_use_id instance-attribute

tool_use_id: Annotated[str, Field(alias='toolUseId')]

The ID of the tool use this result corresponds to.

This MUST match the ID from a previous {@link ToolUseContent}.

CallToolResult

Bases: WireModel

The result returned by the server for a {@link CallToolRequesttools/call} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CallToolResult(WireModel):
    """
    The result returned by the server for a {@link CallToolRequesttools/call} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    content: list[ContentBlock]
    """
    A list of content objects that represent the unstructured result of the tool call.
    """
    is_error: Annotated[bool | None, Field(alias="isError")] = None
    """
    Whether the tool call ended in an error.

    If not set, this is assumed to be false (the call was successful).

    Any errors that originate from the tool SHOULD be reported inside the result
    object, with `isError` set to true, _not_ as an MCP protocol-level error
    response. Otherwise, the LLM would not be able to see that an error occurred
    and self-correct.

    However, any errors in _finding_ the tool, an error indicating that the
    server does not support tool calls, or any other exceptional conditions,
    should be reported as an MCP error response.
    """
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    structured_content: Annotated[Any | None, Field(alias="structuredContent")] = None
    """
    An optional JSON value that represents the structured result of the tool call.

    This can be any JSON value (object, array, string, number, boolean, or null)
    that conforms to the tool's outputSchema if one is defined.
    """

content instance-attribute

content: list[ContentBlock]

A list of content objects that represent the unstructured result of the tool call.

is_error class-attribute instance-attribute

is_error: Annotated[bool | None, Field(alias="isError")] = (
    None
)

Whether the tool call ended in an error.

If not set, this is assumed to be false (the call was successful).

Any errors that originate from the tool SHOULD be reported inside the result object, with isError set to true, not as an MCP protocol-level error response. Otherwise, the LLM would not be able to see that an error occurred and self-correct.

However, any errors in finding the tool, an error indicating that the server does not support tool calls, or any other exceptional conditions, should be reported as an MCP error response.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

structured_content class-attribute instance-attribute

structured_content: Annotated[
    Any | None, Field(alias="structuredContent")
] = None

An optional JSON value that represents the structured result of the tool call.

This can be any JSON value (object, array, string, number, boolean, or null) that conforms to the tool's outputSchema if one is defined.

CancelledNotification

Bases: WireModel

This notification is sent by the client to indicate that it is cancelling a request it previously issued.

On stdio, the server also sends this notification, solely to terminate a {@link SubscriptionsListenRequestsubscriptions/listen} stream: it references the ID of the subscriptions/listen request that opened the stream. Servers MUST NOT use this notification to cancel any other request.

The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.

This notification indicates that the result will be unused, so any associated processing SHOULD cease.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CancelledNotification(WireModel):
    """
    This notification is sent by the client to indicate that it is cancelling a request it previously issued.

    On stdio, the server also sends this notification, solely to terminate a {@link SubscriptionsListenRequestsubscriptions/listen} stream: it references the ID of the `subscriptions/listen` request that opened the stream. Servers MUST NOT use this notification to cancel any other request.

    The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.

    This notification indicates that the result will be unused, so any associated processing SHOULD cease.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/cancelled"]
    params: CancelledNotificationParams

GetPromptResult

Bases: WireModel

The result returned by the server for a {@link GetPromptRequestprompts/get} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class GetPromptResult(WireModel):
    """
    The result returned by the server for a {@link GetPromptRequestprompts/get} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    description: str | None = None
    """
    An optional description for the prompt.
    """
    messages: list[PromptMessage]
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """

description class-attribute instance-attribute

description: str | None = None

An optional description for the prompt.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

LoggingMessageNotification

Bases: WireModel

JSONRPCNotification of a log message passed from server to client. The client opts in by setting "io.modelcontextprotocol/logLevel" in a request's _meta.

Source code in src/mcp/types/v2026_07_28/__init__.py

class LoggingMessageNotification(WireModel):
    """
    JSONRPCNotification of a log message passed from server to client. The client opts in by setting `"io.modelcontextprotocol/logLevel"` in a request's `_meta`.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    jsonrpc: Literal["2.0"]
    method: Literal["notifications/message"]
    params: LoggingMessageNotificationParams

CreateMessageResult

Bases: WireModel

The result returned by the client for a {@link CreateMessageRequestsampling/createMessage} request. The client should inform the user before returning the sampled message, to allow them to inspect the response (human in the loop) and decide whether to allow the server to see it.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CreateMessageResult(WireModel):
    """
    The result returned by the client for a {@link CreateMessageRequestsampling/createMessage} request.
    The client should inform the user before returning the sampled message, to allow them
    to inspect the response (human in the loop) and decide whether to allow the server to see it.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    content: (
        TextContent
        | ImageContent
        | AudioContent
        | ToolUseContent
        | ToolResultContent
        | list[SamplingMessageContentBlock]
    )
    model: str
    """
    The name of the model that generated the message.
    """
    role: Role
    stop_reason: Annotated[str | None, Field(alias="stopReason")] = None
    """
    The reason why sampling stopped, if known.

    Standard values:
    - `"endTurn"`: Natural end of the assistant's turn
    - `"stopSequence"`: A stop sequence was encountered
    - `"maxTokens"`: Maximum token limit was reached
    - `"toolUse"`: The model wants to use one or more tools

    This field is an open string to allow for provider-specific stop reasons.
    """

model instance-attribute

model: str

The name of the model that generated the message.

stop_reason class-attribute instance-attribute

stop_reason: Annotated[
    str | None, Field(alias="stopReason")
] = None

The reason why sampling stopped, if known.

Standard values: - "endTurn": Natural end of the assistant's turn - "stopSequence": A stop sequence was encountered - "maxTokens": Maximum token limit was reached - "toolUse": The model wants to use one or more tools

This field is an open string to allow for provider-specific stop reasons.

InputResponses

Bases: RootModel[dict[str, InputResponse]]

A map of client responses to server-initiated requests. Keys correspond to the keys in the {@link InputRequests} map; values are the client's result for each request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class InputResponses(RootModel[dict[str, InputResponse]]):
    """
    A map of client responses to server-initiated requests.
    Keys correspond to the keys in the {@link InputRequests} map;
    values are the client's result for each request.
    """

    root: dict[str, InputResponse]

SamplingMessage

Bases: WireModel

Describes a message issued to or received from an LLM API.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SamplingMessage(WireModel):
    """
    Describes a message issued to or received from an LLM API.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    content: (
        TextContent
        | ImageContent
        | AudioContent
        | ToolUseContent
        | ToolResultContent
        | list[SamplingMessageContentBlock]
    )
    role: Role

CallToolRequest

Bases: WireModel

Used by the client to invoke a tool provided by the server.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CallToolRequest(WireModel):
    """
    Used by the client to invoke a tool provided by the server.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["tools/call"]
    params: CallToolRequestParams

CallToolRequestParams

Bases: WireModel

Parameters for a tools/call request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CallToolRequestParams(WireModel):
    """
    Parameters for a `tools/call` request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    arguments: dict[str, Any] | None = None
    """
    Arguments to use for the tool call.
    """
    input_responses: Annotated[InputResponses | None, Field(alias="inputResponses")] = None
    name: str
    """
    The name of the tool.
    """
    request_state: Annotated[str | None, Field(alias="requestState")] = None

arguments class-attribute instance-attribute

arguments: dict[str, Any] | None = None

Arguments to use for the tool call.

name instance-attribute

name: str

The name of the tool.

CallToolResultResponse

Bases: WireModel

A successful response from the server for a {@link CallToolRequesttools/call} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CallToolResultResponse(WireModel):
    """
    A successful response from the server for a {@link CallToolRequesttools/call} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: InputRequiredResult | CallToolResult

Elicitation

Bases: WireModel

Present if the client supports elicitation from the server.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Elicitation(WireModel):
    """
    Present if the client supports elicitation from the server.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    form: JSONObject | None = None
    url: JSONObject | None = None

Sampling

Bases: WireModel

Present if the client supports sampling from an LLM.

Source code in src/mcp/types/v2026_07_28/__init__.py

class Sampling(WireModel):
    """
    Present if the client supports sampling from an LLM.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    context: JSONObject | None = None
    """
    Whether the client supports context inclusion via `includeContext` parameter.
    If not declared, servers SHOULD only use `includeContext: "none"` (or omit it).
    """
    tools: JSONObject | None = None
    """
    Whether the client supports tool use via `tools` and `toolChoice` parameters.
    """

context class-attribute instance-attribute

context: JSONObject | None = None

Whether the client supports context inclusion via includeContext parameter. If not declared, servers SHOULD only use includeContext: "none" (or omit it).

tools class-attribute instance-attribute

tools: JSONObject | None = None

Whether the client supports tool use via tools and toolChoice parameters.

ClientCapabilities

Bases: WireModel

Capabilities a client may support. Known capabilities are defined here, in this schema, but this is not a closed set: any client can define its own, additional capabilities.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ClientCapabilities(WireModel):
    """
    Capabilities a client may support. Known capabilities are defined here, in this schema, but this is not a closed set: any client can define its own, additional capabilities.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    elicitation: Elicitation | None = None
    """
    Present if the client supports elicitation from the server.
    """
    experimental: dict[str, JSONObject] | None = None
    """
    Experimental, non-standard capabilities that the client supports.
    """
    extensions: dict[str, JSONObject] | None = None
    """
    Optional MCP extensions that the client supports. Keys are extension identifiers
    (e.g., "io.modelcontextprotocol/oauth-client-credentials"), and values are
    per-extension settings objects. An empty object indicates support with no settings.

    Keys MUST follow the {@link MetaObject`_meta` key naming rules}, with a
    mandatory prefix.
    """
    roots: dict[str, Any] | None = None
    """
    Present if the client supports listing roots.
    """
    sampling: Sampling | None = None
    """
    Present if the client supports sampling from an LLM.
    """

elicitation class-attribute instance-attribute

elicitation: Elicitation | None = None

Present if the client supports elicitation from the server.

experimental class-attribute instance-attribute

experimental: dict[str, JSONObject] | None = None

Experimental, non-standard capabilities that the client supports.

extensions class-attribute instance-attribute

extensions: dict[str, JSONObject] | None = None

Optional MCP extensions that the client supports. Keys are extension identifiers (e.g., "io.modelcontextprotocol/oauth-client-credentials"), and values are per-extension settings objects. An empty object indicates support with no settings.

Keys MUST follow the {@link MetaObject_meta key naming rules}, with a mandatory prefix.

roots class-attribute instance-attribute

roots: dict[str, Any] | None = None

Present if the client supports listing roots.

sampling class-attribute instance-attribute

sampling: Sampling | None = None

Present if the client supports sampling from an LLM.

CompleteRequest

Bases: WireModel

A request from the client to the server, to ask for completion options.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CompleteRequest(WireModel):
    """
    A request from the client to the server, to ask for completion options.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["completion/complete"]
    params: CompleteRequestParams

CompleteRequestParams

Bases: WireModel

Parameters for a completion/complete request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CompleteRequestParams(WireModel):
    """
    Parameters for a `completion/complete` request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    argument: Argument
    """
    The argument's information
    """
    context: Context | None = None
    """
    Additional, optional context for completions
    """
    ref: PromptReference | ResourceTemplateReference

argument instance-attribute

argument: Argument

The argument's information

context class-attribute instance-attribute

context: Context | None = None

Additional, optional context for completions

CreateMessageRequest

Bases: WireModel

A request from the server to sample an LLM via the client. The client has full discretion over which model to select. The client should also inform the user before beginning sampling, to allow them to inspect the request (human in the loop) and decide whether to approve it.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CreateMessageRequest(WireModel):
    """
    A request from the server to sample an LLM via the client. The client has full discretion over which model to select. The client should also inform the user before beginning sampling, to allow them to inspect the request (human in the loop) and decide whether to approve it.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    method: Literal["sampling/createMessage"]
    params: CreateMessageRequestParams

CreateMessageRequestParams

Bases: WireModel

Parameters for a sampling/createMessage request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class CreateMessageRequestParams(WireModel):
    """
    Parameters for a `sampling/createMessage` request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    include_context: Annotated[
        Literal["allServers", "none", "thisServer"] | None,
        Field(alias="includeContext"),
    ] = None
    """
    A request to include context from one or more MCP servers (including the caller), to be attached to the prompt.
    The client MAY ignore this request.

    Default is `"none"`. The values `"thisServer"` and `"allServers"` are deprecated (SEP-2596): servers SHOULD
    omit this field or use `"none"`, and SHOULD only use the deprecated values if the client declares
    {@link ClientCapabilities.sampling.context}.
    """
    max_tokens: Annotated[int, Field(alias="maxTokens")]
    """
    The requested maximum number of tokens to sample (to prevent runaway completions).

    The client MAY choose to sample fewer tokens than the requested maximum.
    """
    messages: list[SamplingMessage]
    metadata: JSONObject | None = None
    """
    Optional metadata to pass through to the LLM provider. The format of this metadata is provider-specific.
    """
    model_preferences: Annotated[ModelPreferences | None, Field(alias="modelPreferences")] = None
    """
    The server's preferences for which model to select. The client MAY ignore these preferences.
    """
    stop_sequences: Annotated[list[str] | None, Field(alias="stopSequences")] = None
    system_prompt: Annotated[str | None, Field(alias="systemPrompt")] = None
    """
    An optional system prompt the server wants to use for sampling. The client MAY modify or omit this prompt.
    """
    temperature: float | None = None
    tool_choice: Annotated[ToolChoice | None, Field(alias="toolChoice")] = None
    """
    Controls how the model uses tools.
    The client MUST return an error if this field is provided but {@link ClientCapabilities.sampling.tools} is not declared.
    Default is `{ mode: "auto" }`.
    """
    tools: list[Tool] | None = None
    """
    Tools that the model may use during generation.
    The client MUST return an error if this field is provided but {@link ClientCapabilities.sampling.tools} is not declared.
    """

include_context class-attribute instance-attribute

include_context: Annotated[
    Literal["allServers", "none", "thisServer"] | None,
    Field(alias="includeContext"),
] = None

A request to include context from one or more MCP servers (including the caller), to be attached to the prompt. The client MAY ignore this request.

Default is "none". The values "thisServer" and "allServers" are deprecated (SEP-2596): servers SHOULD omit this field or use "none", and SHOULD only use the deprecated values if the client declares {@link ClientCapabilities.sampling.context}.

max_tokens instance-attribute

max_tokens: Annotated[int, Field(alias='maxTokens')]

The requested maximum number of tokens to sample (to prevent runaway completions).

The client MAY choose to sample fewer tokens than the requested maximum.

metadata class-attribute instance-attribute

metadata: JSONObject | None = None

Optional metadata to pass through to the LLM provider. The format of this metadata is provider-specific.

model_preferences class-attribute instance-attribute

model_preferences: Annotated[
    ModelPreferences | None, Field(alias="modelPreferences")
] = None

The server's preferences for which model to select. The client MAY ignore these preferences.

system_prompt class-attribute instance-attribute

system_prompt: Annotated[
    str | None, Field(alias="systemPrompt")
] = None

An optional system prompt the server wants to use for sampling. The client MAY modify or omit this prompt.

tool_choice class-attribute instance-attribute

tool_choice: Annotated[
    ToolChoice | None, Field(alias="toolChoice")
] = None

Controls how the model uses tools. The client MUST return an error if this field is provided but {@link ClientCapabilities.sampling.tools} is not declared. Default is { mode: "auto" }.

tools class-attribute instance-attribute

tools: list[Tool] | None = None

Tools that the model may use during generation. The client MUST return an error if this field is provided but {@link ClientCapabilities.sampling.tools} is not declared.

DiscoverRequest

Bases: WireModel

A request from the client asking the server to advertise its supported protocol versions, capabilities, and other metadata. Servers MUST implement server/discover. Clients MAY call it but are not required to — version negotiation can also happen inline via per-request _meta.

Source code in src/mcp/types/v2026_07_28/__init__.py

class DiscoverRequest(WireModel):
    """
    A request from the client asking the server to advertise its supported
    protocol versions, capabilities, and other metadata. Servers **MUST**
    implement `server/discover`. Clients **MAY** call it but are not required
    to — version negotiation can also happen inline via per-request `_meta`.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["server/discover"]
    params: RequestParams

DiscoverResult

Bases: WireModel

The result returned by the server for a {@link DiscoverRequestserver/discover} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class DiscoverResult(WireModel):
    """
    The result returned by the server for a {@link DiscoverRequestserver/discover} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    cache_scope: Annotated[Literal["private", "public"], Field(alias="cacheScope")]
    """
    Indicates the intended scope of the cached response, analogous to HTTP
    `Cache-Control: public` vs `Cache-Control: private`.

    - `"public"`: The response does not contain user-specific data. Any
      client or intermediary (e.g., shared gateway, caching proxy) MAY cache
      the response and serve it across authorization contexts.
    - `"private"`: The response MAY be cached and reused only within the
      same authorization context. Caches MUST NOT be shared across
      authorization contexts (e.g., a different access token requires a
      different cache).
    """
    capabilities: ServerCapabilities
    """
    The capabilities of the server.
    """
    instructions: str | None = None
    """
    Natural-language guidance describing the server and its features.

    This can be used by clients to improve an LLM's understanding of
    available tools (e.g., by including it in a system prompt). It should
    focus on information that helps the model use the server effectively
    and should not duplicate information already in tool descriptions.
    """
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """
    server_info: Annotated[Implementation, Field(alias="serverInfo")]
    """
    Information about the server software implementation.
    """
    supported_versions: Annotated[list[str], Field(alias="supportedVersions")]
    """
    MCP Protocol Versions this server supports. The client should choose a
    version from this list for use in subsequent requests.
    """
    ttl_ms: Annotated[int, Field(alias="ttlMs", ge=0)]
    """
    A hint from the server indicating how long (in milliseconds) the
    client MAY cache this response before re-fetching. Semantics are
    analogous to HTTP Cache-Control max-age.

    - If 0, The response SHOULD be considered immediately stale,
      The client MAY re-fetch every time the result is needed.
    - If positive, the client SHOULD consider the result fresh for this many
      milliseconds after receiving the response.
    """

cache_scope instance-attribute

cache_scope: Annotated[
    Literal["private", "public"], Field(alias="cacheScope")
]

Indicates the intended scope of the cached response, analogous to HTTP Cache-Control: public vs Cache-Control: private.

• "public": The response does not contain user-specific data. Any client or intermediary (e.g., shared gateway, caching proxy) MAY cache the response and serve it across authorization contexts.
• "private": The response MAY be cached and reused only within the same authorization context. Caches MUST NOT be shared across authorization contexts (e.g., a different access token requires a different cache).

capabilities instance-attribute

capabilities: ServerCapabilities

The capabilities of the server.

instructions class-attribute instance-attribute

instructions: str | None = None

Natural-language guidance describing the server and its features.

This can be used by clients to improve an LLM's understanding of available tools (e.g., by including it in a system prompt). It should focus on information that helps the model use the server effectively and should not duplicate information already in tool descriptions.

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

server_info instance-attribute

server_info: Annotated[
    Implementation, Field(alias="serverInfo")
]

Information about the server software implementation.

supported_versions instance-attribute

supported_versions: Annotated[
    list[str], Field(alias="supportedVersions")
]

MCP Protocol Versions this server supports. The client should choose a version from this list for use in subsequent requests.

ttl_ms instance-attribute

ttl_ms: Annotated[int, Field(alias='ttlMs', ge=0)]

A hint from the server indicating how long (in milliseconds) the client MAY cache this response before re-fetching. Semantics are analogous to HTTP Cache-Control max-age.

• If 0, The response SHOULD be considered immediately stale, The client MAY re-fetch every time the result is needed.
• If positive, the client SHOULD consider the result fresh for this many milliseconds after receiving the response.

DiscoverResultResponse

Bases: WireModel

A successful response from the server for a {@link DiscoverRequestserver/discover} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class DiscoverResultResponse(WireModel):
    """
    A successful response from the server for a {@link DiscoverRequestserver/discover} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: DiscoverResult

GetPromptRequest

Bases: WireModel

Used by the client to get a prompt provided by the server.

Source code in src/mcp/types/v2026_07_28/__init__.py

class GetPromptRequest(WireModel):
    """
    Used by the client to get a prompt provided by the server.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["prompts/get"]
    params: GetPromptRequestParams

GetPromptRequestParams

Bases: WireModel

Parameters for a prompts/get request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class GetPromptRequestParams(WireModel):
    """
    Parameters for a `prompts/get` request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    arguments: dict[str, str] | None = None
    """
    Arguments to use for templating the prompt.
    """
    input_responses: Annotated[InputResponses | None, Field(alias="inputResponses")] = None
    name: str
    """
    The name of the prompt or prompt template.
    """
    request_state: Annotated[str | None, Field(alias="requestState")] = None

arguments class-attribute instance-attribute

arguments: dict[str, str] | None = None

Arguments to use for templating the prompt.

name instance-attribute

name: str

The name of the prompt or prompt template.

GetPromptResultResponse

Bases: WireModel

A successful response from the server for a {@link GetPromptRequestprompts/get} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class GetPromptResultResponse(WireModel):
    """
    A successful response from the server for a {@link GetPromptRequestprompts/get} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: InputRequiredResult | GetPromptResult

InputRequiredResult

Bases: WireModel

An InputRequiredResult sent by the server to indicate that additional input is needed before the request can be completed.

At least one of inputRequests or requestState MUST be present.

Source code in src/mcp/types/v2026_07_28/__init__.py

class InputRequiredResult(WireModel):
    """
    An InputRequiredResult sent by the server to indicate that additional input is needed
    before the request can be completed.

    At least one of `inputRequests` or `requestState` MUST be present.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[MetaObject | None, Field(alias="_meta")] = None
    input_requests: Annotated[InputRequests | None, Field(alias="inputRequests")] = None
    request_state: Annotated[str | None, Field(alias="requestState")] = None
    result_type: Annotated[str, Field(alias="resultType")]
    """
    Indicates the type of the result, which allows the client to determine
    how to parse the result object.

    Servers implementing this protocol version MUST include this field.
    For backward compatibility, when a client receives a result from a
    server implementing an earlier protocol version (which does not include
    `resultType`), the client MUST treat the absent field as `"complete"`.
    """

result_type instance-attribute

result_type: Annotated[str, Field(alias='resultType')]

Indicates the type of the result, which allows the client to determine how to parse the result object.

Servers implementing this protocol version MUST include this field. For backward compatibility, when a client receives a result from a server implementing an earlier protocol version (which does not include resultType), the client MUST treat the absent field as "complete".

ListPromptsRequest

Bases: WireModel

Sent from the client to request a list of prompts and prompt templates the server has.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListPromptsRequest(WireModel):
    """
    Sent from the client to request a list of prompts and prompt templates the server has.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["prompts/list"]
    params: PaginatedRequestParams

ListResourceTemplatesRequest

Bases: WireModel

Sent from the client to request a list of resource templates the server has.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourceTemplatesRequest(WireModel):
    """
    Sent from the client to request a list of resource templates the server has.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["resources/templates/list"]
    params: PaginatedRequestParams

ListResourcesRequest

Bases: WireModel

Sent from the client to request a list of resources the server has.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListResourcesRequest(WireModel):
    """
    Sent from the client to request a list of resources the server has.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["resources/list"]
    params: PaginatedRequestParams

ListToolsRequest

Bases: WireModel

Sent from the client to request a list of tools the server has.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ListToolsRequest(WireModel):
    """
    Sent from the client to request a list of tools the server has.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["tools/list"]
    params: PaginatedRequestParams

Data

Bases: WireModel

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

Source code in src/mcp/types/v2026_07_28/__init__.py

class Data(WireModel):
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    required_capabilities: Annotated[ClientCapabilities, Field(alias="requiredCapabilities")]
    """
    The capabilities the server requires from the client to process this request.
    """

required_capabilities instance-attribute

required_capabilities: Annotated[
    ClientCapabilities, Field(alias="requiredCapabilities")
]

The capabilities the server requires from the client to process this request.

Error2

Bases: Error

Source code in src/mcp/types/v2026_07_28/__init__.py

class Error2(Error):
    model_config = ConfigDict(
        extra="ignore",
    )
    code: Literal[-32021]
    """
    The error type that occurred.
    """
    data: Data
    """
    Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).
    """

code instance-attribute

code: Literal[-32021]

The error type that occurred.

data instance-attribute

data: Data

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

MissingRequiredClientCapabilityError

Bases: WireModel

Returned when processing a request requires a capability the client did not declare in clientCapabilities. For HTTP, the response status code MUST be 400 Bad Request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class MissingRequiredClientCapabilityError(WireModel):
    """
    Returned when processing a request requires a capability the client did not
    declare in `clientCapabilities`. For HTTP, the response status code MUST be
    `400 Bad Request`.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    error: Error2
    id: RequestId | None = None
    jsonrpc: Literal["2.0"]

PaginatedRequestParams

Bases: WireModel

Common params for paginated requests.

Source code in src/mcp/types/v2026_07_28/__init__.py

class PaginatedRequestParams(WireModel):
    """
    Common params for paginated requests.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    cursor: str | None = None
    """
    An opaque token representing the current pagination position.
    If provided, the server should return results starting after this cursor.
    """

cursor class-attribute instance-attribute

cursor: str | None = None

An opaque token representing the current pagination position. If provided, the server should return results starting after this cursor.

ReadResourceRequest

Bases: WireModel

Sent from the client to the server, to read a specific resource URI.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ReadResourceRequest(WireModel):
    """
    Sent from the client to the server, to read a specific resource URI.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["resources/read"]
    params: ReadResourceRequestParams

ReadResourceRequestParams

Bases: WireModel

Parameters for a resources/read request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ReadResourceRequestParams(WireModel):
    """
    Parameters for a `resources/read` request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    input_responses: Annotated[InputResponses | None, Field(alias="inputResponses")] = None
    request_state: Annotated[str | None, Field(alias="requestState")] = None
    uri: str
    """
    The URI of the resource. The URI can use any protocol; it is up to the server how to interpret it.
    """

uri instance-attribute

uri: str

The URI of the resource. The URI can use any protocol; it is up to the server how to interpret it.

ReadResourceResultResponse

Bases: WireModel

A successful response from the server for a {@link ReadResourceRequestresources/read} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ReadResourceResultResponse(WireModel):
    """
    A successful response from the server for a {@link ReadResourceRequestresources/read} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    result: InputRequiredResult | ReadResourceResult

RequestMetaObject

Bases: WireModel

Extends {@link MetaObject} with additional request-specific fields. All key naming rules from MetaObject apply.

Source code in src/mcp/types/v2026_07_28/__init__.py

class RequestMetaObject(WireModel):
    """
    Extends {@link MetaObject} with additional request-specific fields. All key naming rules from `MetaObject` apply.
    """

    model_config = ConfigDict(
        extra="allow",
    )
    io_modelcontextprotocol_client_capabilities: Annotated[
        ClientCapabilities, Field(alias="io.modelcontextprotocol/clientCapabilities")
    ]
    """
    The client's capabilities for this specific request. Required.

    Capabilities are declared per-request rather than once at initialization;
    an empty object means the client supports no optional capabilities.
    Servers MUST NOT infer capabilities from prior requests.
    """
    io_modelcontextprotocol_client_info: Annotated[Implementation, Field(alias="io.modelcontextprotocol/clientInfo")]
    """
    Identifies the client software making the request. Required.

    The {@link Implementation} schema requires `name` and `version`; other
    fields are optional.
    """
    io_modelcontextprotocol_log_level: Annotated[
        LoggingLevel | None, Field(alias="io.modelcontextprotocol/logLevel")
    ] = None
    """
    The desired log level for this request. Optional.

    If absent, the server MUST NOT send any {@link LoggingMessageNotificationnotifications/message}
    notifications for this request. The client opts in to log messages by
    explicitly setting a level. Replaces the former `logging/setLevel` RPC.
    """
    io_modelcontextprotocol_protocol_version: Annotated[str, Field(alias="io.modelcontextprotocol/protocolVersion")]
    """
    The MCP Protocol Version being used for this request. Required.

    For the HTTP transport, this value MUST match the `MCP-Protocol-Version`
    header; otherwise the server MUST return a `400 Bad Request`. If the
    server does not support the requested version, it MUST return an
    {@link UnsupportedProtocolVersionError}.
    """
    progress_token: Annotated[ProgressToken | None, Field(alias="progressToken")] = None
    """
    If specified, the caller is requesting out-of-band progress notifications for this request (as represented by {@link ProgressNotificationnotifications/progress}). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.
    """

io_modelcontextprotocol_client_capabilities instance-attribute

io_modelcontextprotocol_client_capabilities: Annotated[
    ClientCapabilities,
    Field(
        alias="io.modelcontextprotocol/clientCapabilities"
    ),
]

The client's capabilities for this specific request. Required.

Capabilities are declared per-request rather than once at initialization; an empty object means the client supports no optional capabilities. Servers MUST NOT infer capabilities from prior requests.

io_modelcontextprotocol_client_info instance-attribute

io_modelcontextprotocol_client_info: Annotated[
    Implementation,
    Field(alias="io.modelcontextprotocol/clientInfo"),
]

Identifies the client software making the request. Required.

The {@link Implementation} schema requires name and version; other fields are optional.

io_modelcontextprotocol_log_level class-attribute instance-attribute

io_modelcontextprotocol_log_level: Annotated[
    LoggingLevel | None,
    Field(alias="io.modelcontextprotocol/logLevel"),
] = None

The desired log level for this request. Optional.

If absent, the server MUST NOT send any {@link LoggingMessageNotificationnotifications/message} notifications for this request. The client opts in to log messages by explicitly setting a level. Replaces the former logging/setLevel RPC.

io_modelcontextprotocol_protocol_version instance-attribute

io_modelcontextprotocol_protocol_version: Annotated[
    str,
    Field(alias="io.modelcontextprotocol/protocolVersion"),
]

The MCP Protocol Version being used for this request. Required.

For the HTTP transport, this value MUST match the MCP-Protocol-Version header; otherwise the server MUST return a 400 Bad Request. If the server does not support the requested version, it MUST return an {@link UnsupportedProtocolVersionError}.

progress_token class-attribute instance-attribute

progress_token: Annotated[
    ProgressToken | None, Field(alias="progressToken")
] = None

If specified, the caller is requesting out-of-band progress notifications for this request (as represented by {@link ProgressNotificationnotifications/progress}). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.

RequestParams

Bases: WireModel

Common params for any request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class RequestParams(WireModel):
    """
    Common params for any request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]

ResourceRequestParams

Bases: WireModel

Common params for resource-related requests.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ResourceRequestParams(WireModel):
    """
    Common params for resource-related requests.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    uri: str
    """
    The URI of the resource. The URI can use any protocol; it is up to the server how to interpret it.
    """

uri instance-attribute

uri: str

The URI of the resource. The URI can use any protocol; it is up to the server how to interpret it.

ServerCapabilities

Bases: WireModel

Capabilities that a server may support. Known capabilities are defined here, in this schema, but this is not a closed set: any server can define its own, additional capabilities.

Source code in src/mcp/types/v2026_07_28/__init__.py

class ServerCapabilities(WireModel):
    """
    Capabilities that a server may support. Known capabilities are defined here, in this schema, but this is not a closed set: any server can define its own, additional capabilities.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    completions: JSONObject | None = None
    """
    Present if the server supports argument autocompletion suggestions.
    """
    experimental: dict[str, JSONObject] | None = None
    """
    Experimental, non-standard capabilities that the server supports.
    """
    extensions: dict[str, JSONObject] | None = None
    """
    Optional MCP extensions that the server supports. Keys are extension identifiers
    (e.g., "io.modelcontextprotocol/tasks"), and values are per-extension settings
    objects. An empty object indicates support with no settings.

    Keys MUST follow the {@link MetaObject`_meta` key naming rules}, with a
    mandatory prefix.
    """
    logging: JSONObject | None = None
    """
    Present if the server supports sending log messages to the client.
    """
    prompts: Prompts | None = None
    """
    Present if the server offers any prompt templates.
    """
    resources: Resources | None = None
    """
    Present if the server offers any resources to read.
    """
    tools: Tools | None = None
    """
    Present if the server offers any tools to call.
    """

completions class-attribute instance-attribute

completions: JSONObject | None = None

Present if the server supports argument autocompletion suggestions.

experimental class-attribute instance-attribute

experimental: dict[str, JSONObject] | None = None

Experimental, non-standard capabilities that the server supports.

extensions class-attribute instance-attribute

extensions: dict[str, JSONObject] | None = None

Optional MCP extensions that the server supports. Keys are extension identifiers (e.g., "io.modelcontextprotocol/tasks"), and values are per-extension settings objects. An empty object indicates support with no settings.

Keys MUST follow the {@link MetaObject_meta key naming rules}, with a mandatory prefix.

logging class-attribute instance-attribute

logging: JSONObject | None = None

Present if the server supports sending log messages to the client.

prompts class-attribute instance-attribute

prompts: Prompts | None = None

Present if the server offers any prompt templates.

resources class-attribute instance-attribute

resources: Resources | None = None

Present if the server offers any resources to read.

tools class-attribute instance-attribute

tools: Tools | None = None

Present if the server offers any tools to call.

SubscriptionsListenRequest

Bases: WireModel

Sent from the client to open a long-lived channel for receiving notifications outside the context of a specific request. Replaces the previous HTTP GET endpoint and ensures consistent behavior between HTTP and STDIO.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SubscriptionsListenRequest(WireModel):
    """
    Sent from the client to open a long-lived channel for receiving notifications
    outside the context of a specific request. Replaces the previous HTTP GET
    endpoint and ensures consistent behavior between HTTP and STDIO.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    id: RequestId
    jsonrpc: Literal["2.0"]
    method: Literal["subscriptions/listen"]
    params: SubscriptionsListenRequestParams

SubscriptionsListenRequestParams

Bases: WireModel

Parameters for a {@link SubscriptionsListenRequestsubscriptions/listen} request.

Source code in src/mcp/types/v2026_07_28/__init__.py

class SubscriptionsListenRequestParams(WireModel):
    """
    Parameters for a {@link SubscriptionsListenRequestsubscriptions/listen} request.
    """

    model_config = ConfigDict(
        extra="ignore",
    )
    meta: Annotated[RequestMetaObject, Field(alias="_meta")]
    notifications: SubscriptionFilter
    """
    The notifications the client opts in to on this stream. The server
    **MUST NOT** send notification types the client has not explicitly
    requested.
    """

notifications instance-attribute

notifications: SubscriptionFilter

The notifications the client opts in to on this stream. The server MUST NOT send notification types the client has not explicitly requested.

InputRequests

Bases: RootModel[dict[str, InputRequest]]

A map of server-initiated requests that the client must fulfill. Keys are server-assigned identifiers; values are the request objects.

Source code in src/mcp/types/v2026_07_28/__init__.py

class InputRequests(RootModel[dict[str, InputRequest]]):
    """
    A map of server-initiated requests that the client must fulfill.
    Keys are server-assigned identifiers; values are the request objects.
    """

    root: dict[str, InputRequest]