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TokenVerifier

Bases: Protocol

Protocol for verifying bearer tokens.

Source code in src/mcp/server/auth/provider.py 
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class TokenVerifier(Protocol):
    """Protocol for verifying bearer tokens."""

    async def verify_token(self, token: str) -> AccessToken | None:
        """Verify a bearer token and return access info if valid."""

verify_token async 

verify_token(token: str) -> AccessToken | None

Verify a bearer token and return access info if valid.

Source code in src/mcp/server/auth/provider.py 
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async def verify_token(self, token: str) -> AccessToken | None:
    """Verify a bearer token and return access info if valid."""

OAuthAuthorizationServerProvider

Bases: Protocol, Generic[AuthorizationCodeT, RefreshTokenT, AccessTokenT]

Source code in src/mcp/server/auth/provider.py 
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class OAuthAuthorizationServerProvider(Protocol, Generic[AuthorizationCodeT, RefreshTokenT, AccessTokenT]):
    async def get_client(self, client_id: str) -> OAuthClientInformationFull | None:
        """Retrieves client information by client ID.

        Implementors MAY raise NotImplementedError if dynamic client registration is
        disabled in ClientRegistrationOptions.

        Args:
            client_id: The ID of the client to retrieve.

        Returns:
            The client information, or None if the client does not exist.
        """

    async def register_client(self, client_info: OAuthClientInformationFull) -> None:
        """Saves client information as part of registering it.

        Implementors MAY raise NotImplementedError if dynamic client registration is
        disabled in ClientRegistrationOptions.

        Args:
            client_info: The client metadata to register.

        Raises:
            RegistrationError: If the client metadata is invalid.
        """

    async def authorize(self, client: OAuthClientInformationFull, params: AuthorizationParams) -> str:
        """Handle the /authorize endpoint and return a URL that the client
        will be redirected to.

        Many MCP implementations will redirect to a third-party provider to perform
        a second OAuth exchange with that provider. In this sort of setup, the client
        has an OAuth connection with the MCP server, and the MCP server has an OAuth
        connection with the 3rd-party provider. At the end of this flow, the client
        should be redirected to the redirect_uri from params.redirect_uri.

        +--------+     +------------+     +-------------------+
        |        |     |            |     |                   |
        | Client | --> | MCP Server | --> | 3rd Party OAuth   |
        |        |     |            |     | Server            |
        +--------+     +------------+     +-------------------+
                            |   ^                  |
        +------------+      |   |                  |
        |            |      |   |    Redirect      |
        |redirect_uri|<-----+   +------------------+
        |            |
        +------------+

        Implementations will need to define another handler on the MCP server's return
        flow to perform the second redirect, and generate and store an authorization
        code as part of completing the OAuth authorization step.

        Implementations SHOULD generate an authorization code with at least 160 bits of
        entropy,
        and MUST generate an authorization code with at least 128 bits of entropy.
        See https://datatracker.ietf.org/doc/html/rfc6749#section-10.10.

        Args:
            client: The client requesting authorization.
            params: The parameters of the authorization request.

        Returns:
            A URL to redirect the client to for authorization.

        Raises:
            AuthorizeError: If the authorization request is invalid.
        """
        ...

    async def load_authorization_code(
        self, client: OAuthClientInformationFull, authorization_code: str
    ) -> AuthorizationCodeT | None:
        """Loads an AuthorizationCode by its code.

        Args:
            client: The client that requested the authorization code.
            authorization_code: The authorization code to get the challenge for.

        Returns:
            The AuthorizationCode, or None if not found.
        """
        ...

    async def exchange_authorization_code(
        self, client: OAuthClientInformationFull, authorization_code: AuthorizationCodeT
    ) -> OAuthToken:
        """Exchanges an authorization code for an access token and refresh token.

        Args:
            client: The client exchanging the authorization code.
            authorization_code: The authorization code to exchange.

        Returns:
            The OAuth token, containing access and refresh tokens.

        Raises:
            TokenError: If the request is invalid.
        """
        ...

    async def load_refresh_token(self, client: OAuthClientInformationFull, refresh_token: str) -> RefreshTokenT | None:
        """Loads a RefreshToken by its token string.

        Args:
            client: The client that is requesting to load the refresh token.
            refresh_token: The refresh token string to load.

        Returns:
            The RefreshToken object if found, or None if not found.
        """
        ...

    async def exchange_refresh_token(
        self,
        client: OAuthClientInformationFull,
        refresh_token: RefreshTokenT,
        scopes: list[str],
    ) -> OAuthToken:
        """Exchanges a refresh token for an access token and refresh token.

        Implementations SHOULD rotate both the access token and refresh token.

        Args:
            client: The client exchanging the refresh token.
            refresh_token: The refresh token to exchange.
            scopes: Optional scopes to request with the new access token.

        Returns:
            The OAuth token, containing access and refresh tokens.

        Raises:
            TokenError: If the request is invalid.
        """
        ...

    async def load_access_token(self, token: str) -> AccessTokenT | None:
        """Loads an access token by its token string.

        Args:
            token: The access token to verify.

        Returns:
            The access token, or None if the token is invalid.
        """

    async def revoke_token(
        self,
        token: AccessTokenT | RefreshTokenT,
    ) -> None:
        """Revokes an access or refresh token.

        If the given token is invalid or already revoked, this method should do nothing.

        Implementations SHOULD revoke both the access token and its corresponding
        refresh token, regardless of which of the access token or refresh token is
        provided.

        Args:
            token: The token to revoke.
        """

get_client async 

get_client(
    client_id: str,
) -> OAuthClientInformationFull | None

Retrieves client information by client ID.

Implementors MAY raise NotImplementedError if dynamic client registration is disabled in ClientRegistrationOptions.

Parameters:

Name Type Description Default
client_id str

The ID of the client to retrieve.

 required

Returns:

Type Description
OAuthClientInformationFull | None

The client information, or None if the client does not exist.
Source code in src/mcp/server/auth/provider.py 
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async def get_client(self, client_id: str) -> OAuthClientInformationFull | None:
    """Retrieves client information by client ID.

    Implementors MAY raise NotImplementedError if dynamic client registration is
    disabled in ClientRegistrationOptions.

    Args:
        client_id: The ID of the client to retrieve.

    Returns:
        The client information, or None if the client does not exist.
    """

register_client async 

register_client(
    client_info: OAuthClientInformationFull,
) -> None

Saves client information as part of registering it.

Implementors MAY raise NotImplementedError if dynamic client registration is disabled in ClientRegistrationOptions.

Parameters:

Name Type Description Default
client_info OAuthClientInformationFull

The client metadata to register.

 required

Raises:

Type Description
RegistrationError

If the client metadata is invalid.
Source code in src/mcp/server/auth/provider.py 
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async def register_client(self, client_info: OAuthClientInformationFull) -> None:
    """Saves client information as part of registering it.

    Implementors MAY raise NotImplementedError if dynamic client registration is
    disabled in ClientRegistrationOptions.

    Args:
        client_info: The client metadata to register.

    Raises:
        RegistrationError: If the client metadata is invalid.
    """

authorize async 

authorize(
    client: OAuthClientInformationFull,
    params: AuthorizationParams,
) -> str

Handle the /authorize endpoint and return a URL that the client will be redirected to.

Many MCP implementations will redirect to a third-party provider to perform a second OAuth exchange with that provider. In this sort of setup, the client has an OAuth connection with the MCP server, and the MCP server has an OAuth connection with the 3rd-party provider. At the end of this flow, the client should be redirected to the redirect_uri from params.redirect_uri.

+--------+ +------------+ +-------------------+ | | | | | | | Client | --> | MCP Server | --> | 3rd Party OAuth | | | | | | Server | +--------+ +------------+ +-------------------+ | ^ | +------------+ | | | | | | | Redirect | |redirect_uri|<-----+ +------------------+ | | +------------+

Implementations will need to define another handler on the MCP server's return flow to perform the second redirect, and generate and store an authorization code as part of completing the OAuth authorization step.

Implementations SHOULD generate an authorization code with at least 160 bits of entropy, and MUST generate an authorization code with at least 128 bits of entropy. See https://datatracker.ietf.org/doc/html/rfc6749#section-10.10.

Parameters:

Name Type Description Default
client OAuthClientInformationFull

The client requesting authorization.

 required
params AuthorizationParams

The parameters of the authorization request.

 required

Returns:

Type Description
str

A URL to redirect the client to for authorization.

Raises:

Type Description
AuthorizeError

If the authorization request is invalid.
Source code in src/mcp/server/auth/provider.py 
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async def authorize(self, client: OAuthClientInformationFull, params: AuthorizationParams) -> str:
    """Handle the /authorize endpoint and return a URL that the client
    will be redirected to.

    Many MCP implementations will redirect to a third-party provider to perform
    a second OAuth exchange with that provider. In this sort of setup, the client
    has an OAuth connection with the MCP server, and the MCP server has an OAuth
    connection with the 3rd-party provider. At the end of this flow, the client
    should be redirected to the redirect_uri from params.redirect_uri.

    +--------+     +------------+     +-------------------+
    |        |     |            |     |                   |
    | Client | --> | MCP Server | --> | 3rd Party OAuth   |
    |        |     |            |     | Server            |
    +--------+     +------------+     +-------------------+
                        |   ^                  |
    +------------+      |   |                  |
    |            |      |   |    Redirect      |
    |redirect_uri|<-----+   +------------------+
    |            |
    +------------+

    Implementations will need to define another handler on the MCP server's return
    flow to perform the second redirect, and generate and store an authorization
    code as part of completing the OAuth authorization step.

    Implementations SHOULD generate an authorization code with at least 160 bits of
    entropy,
    and MUST generate an authorization code with at least 128 bits of entropy.
    See https://datatracker.ietf.org/doc/html/rfc6749#section-10.10.

    Args:
        client: The client requesting authorization.
        params: The parameters of the authorization request.

    Returns:
        A URL to redirect the client to for authorization.

    Raises:
        AuthorizeError: If the authorization request is invalid.
    """
    ...

load_authorization_code async 

load_authorization_code(
    client: OAuthClientInformationFull,
    authorization_code: str,
) -> AuthorizationCodeT | None

Loads an AuthorizationCode by its code.

Parameters:

Name Type Description Default
client OAuthClientInformationFull

The client that requested the authorization code.

 required
authorization_code str

The authorization code to get the challenge for.

 required

Returns:

Type Description
AuthorizationCodeT | None

The AuthorizationCode, or None if not found.
Source code in src/mcp/server/auth/provider.py 
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async def load_authorization_code(
    self, client: OAuthClientInformationFull, authorization_code: str
) -> AuthorizationCodeT | None:
    """Loads an AuthorizationCode by its code.

    Args:
        client: The client that requested the authorization code.
        authorization_code: The authorization code to get the challenge for.

    Returns:
        The AuthorizationCode, or None if not found.
    """
    ...

exchange_authorization_code async 

exchange_authorization_code(
    client: OAuthClientInformationFull,
    authorization_code: AuthorizationCodeT,
) -> OAuthToken

Exchanges an authorization code for an access token and refresh token.

Parameters:

Name Type Description Default
client OAuthClientInformationFull

The client exchanging the authorization code.

 required
authorization_code AuthorizationCodeT

The authorization code to exchange.

 required

Returns:

Type Description
OAuthToken

The OAuth token, containing access and refresh tokens.

Raises:

Type Description
TokenError

If the request is invalid.
Source code in src/mcp/server/auth/provider.py 
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async def exchange_authorization_code(
    self, client: OAuthClientInformationFull, authorization_code: AuthorizationCodeT
) -> OAuthToken:
    """Exchanges an authorization code for an access token and refresh token.

    Args:
        client: The client exchanging the authorization code.
        authorization_code: The authorization code to exchange.

    Returns:
        The OAuth token, containing access and refresh tokens.

    Raises:
        TokenError: If the request is invalid.
    """
    ...

load_refresh_token async 

load_refresh_token(
    client: OAuthClientInformationFull, refresh_token: str
) -> RefreshTokenT | None

Loads a RefreshToken by its token string.

Parameters:

Name Type Description Default
client OAuthClientInformationFull

The client that is requesting to load the refresh token.

 required
refresh_token str

The refresh token string to load.

 required

Returns:

Type Description
RefreshTokenT | None

The RefreshToken object if found, or None if not found.
Source code in src/mcp/server/auth/provider.py 
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async def load_refresh_token(self, client: OAuthClientInformationFull, refresh_token: str) -> RefreshTokenT | None:
    """Loads a RefreshToken by its token string.

    Args:
        client: The client that is requesting to load the refresh token.
        refresh_token: The refresh token string to load.

    Returns:
        The RefreshToken object if found, or None if not found.
    """
    ...

exchange_refresh_token async 

exchange_refresh_token(
    client: OAuthClientInformationFull,
    refresh_token: RefreshTokenT,
    scopes: list[str],
) -> OAuthToken

Exchanges a refresh token for an access token and refresh token.

Implementations SHOULD rotate both the access token and refresh token.

Parameters:

Name Type Description Default
client OAuthClientInformationFull

The client exchanging the refresh token.

 required
refresh_token RefreshTokenT

The refresh token to exchange.

 required
scopes list[str]

Optional scopes to request with the new access token.

 required

Returns:

Type Description
OAuthToken

The OAuth token, containing access and refresh tokens.

Raises:

Type Description
TokenError

If the request is invalid.
Source code in src/mcp/server/auth/provider.py 
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async def exchange_refresh_token(
    self,
    client: OAuthClientInformationFull,
    refresh_token: RefreshTokenT,
    scopes: list[str],
) -> OAuthToken:
    """Exchanges a refresh token for an access token and refresh token.

    Implementations SHOULD rotate both the access token and refresh token.

    Args:
        client: The client exchanging the refresh token.
        refresh_token: The refresh token to exchange.
        scopes: Optional scopes to request with the new access token.

    Returns:
        The OAuth token, containing access and refresh tokens.

    Raises:
        TokenError: If the request is invalid.
    """
    ...

load_access_token async 

load_access_token(token: str) -> AccessTokenT | None

Loads an access token by its token string.

Parameters:

Name Type Description Default
token str

The access token to verify.

 required

Returns:

Type Description
AccessTokenT | None

The access token, or None if the token is invalid.
Source code in src/mcp/server/auth/provider.py 
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async def load_access_token(self, token: str) -> AccessTokenT | None:
    """Loads an access token by its token string.

    Args:
        token: The access token to verify.

    Returns:
        The access token, or None if the token is invalid.
    """

revoke_token async 

revoke_token(token: AccessTokenT | RefreshTokenT) -> None

Revokes an access or refresh token.

If the given token is invalid or already revoked, this method should do nothing.

Implementations SHOULD revoke both the access token and its corresponding refresh token, regardless of which of the access token or refresh token is provided.

Parameters:

Name Type Description Default
token AccessTokenT | RefreshTokenT

The token to revoke.

 required
Source code in src/mcp/server/auth/provider.py 
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async def revoke_token(
    self,
    token: AccessTokenT | RefreshTokenT,
) -> None:
    """Revokes an access or refresh token.

    If the given token is invalid or already revoked, this method should do nothing.

    Implementations SHOULD revoke both the access token and its corresponding
    refresh token, regardless of which of the access token or refresh token is
    provided.

    Args:
        token: The token to revoke.
    """

ProviderTokenVerifier

Bases: TokenVerifier

Token verifier that uses an OAuthAuthorizationServerProvider.

This is provided for backwards compatibility with existing auth_server_provider configurations. For new implementations using AS/RS separation, consider using the TokenVerifier protocol with a dedicated implementation like IntrospectionTokenVerifier.

Source code in src/mcp/server/auth/provider.py 
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class ProviderTokenVerifier(TokenVerifier):
    """Token verifier that uses an OAuthAuthorizationServerProvider.

    This is provided for backwards compatibility with existing auth_server_provider
    configurations. For new implementations using AS/RS separation, consider using
    the TokenVerifier protocol with a dedicated implementation like IntrospectionTokenVerifier.
    """

    def __init__(self, provider: "OAuthAuthorizationServerProvider[AuthorizationCode, RefreshToken, AccessToken]"):
        self.provider = provider

    async def verify_token(self, token: str) -> AccessToken | None:
        """Verify token using the provider's load_access_token method."""
        return await self.provider.load_access_token(token)

verify_token async 

verify_token(token: str) -> AccessToken | None

Verify token using the provider's load_access_token method.

Source code in src/mcp/server/auth/provider.py 
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async def verify_token(self, token: str) -> AccessToken | None:
    """Verify token using the provider's load_access_token method."""
    return await self.provider.load_access_token(token)