`fastmcp.client.auth.oauth`

Functions

`check_if_auth_required`

check_if_auth_required(mcp_url: str, httpx_kwargs: dict[str, Any] | None = None) -> bool

Check if the MCP endpoint requires authentication by making a test request. Returns:

True if auth appears to be required, False otherwise

Classes

`ClientNotFoundError`

Raised when OAuth client credentials are not found on the server.

`ExpiredClientRegistrationError`

Raised when dynamic registration returns an expired client secret.

`TokenStorageAdapter`

Methods:

`clear`

clear(self) -> None

`get_tokens`

get_tokens(self) -> OAuthToken | None

`set_tokens`

set_tokens(self, tokens: OAuthToken) -> None

`get_token_expiry`

get_token_expiry(self) -> float | None

`get_client_info`

get_client_info(self) -> OAuthClientInformationFull | None

`set_client_info`

set_client_info(self, client_info: OAuthClientInformationFull) -> None

`OAuth`

OAuth client provider for MCP servers with browser-based authentication. This class provides OAuth authentication for FastMCP clients by opening a browser for user authorization and running a local callback server. Methods:

`redirect_handler`

redirect_handler(self, authorization_url: str) -> None

Open browser for authorization, with pre-flight check for invalid client.

`callback_handler`

callback_handler(self) -> AuthorizationCodeResult

Handle OAuth callback and return the authorization code result.

`async_auth_flow`

async_auth_flow(self, request: httpx2.Request) -> AsyncGenerator[httpx2.Request, httpx2.Response]

HTTPX auth flow with automatic retry on stale cached credentials. If the OAuth flow fails due to invalid/stale client credentials, clears the cache and retries once with fresh registration.

⌘I

fastmcp.apps

fastmcp.cli

fastmcp.client

fastmcp.experimental

fastmcp.prompts

fastmcp.resources

fastmcp.server

fastmcp.tools

fastmcp.utilities

oauth

`fastmcp.client.auth.oauth`

Functions

`check_if_auth_required`

Classes

`ClientNotFoundError`

`ExpiredClientRegistrationError`

`TokenStorageAdapter`

`clear`

`get_tokens`

`set_tokens`

`get_token_expiry`

`get_client_info`

`set_client_info`

`OAuth`

`redirect_handler`

`callback_handler`

`async_auth_flow`

​fastmcp.client.auth.oauth

​Functions

​check_if_auth_required

​Classes

​ClientNotFoundError

​ExpiredClientRegistrationError

​TokenStorageAdapter

​clear

​get_tokens

​set_tokens

​get_token_expiry

​get_client_info

​set_client_info

​OAuth

​redirect_handler

​callback_handler

​async_auth_flow

`fastmcp.client.auth.oauth`

Functions

`check_if_auth_required`

Classes

`ClientNotFoundError`

`ExpiredClientRegistrationError`

`TokenStorageAdapter`

`clear`

`get_tokens`

`set_tokens`

`get_token_expiry`

`get_client_info`

`set_client_info`

`OAuth`

`redirect_handler`

`callback_handler`

`async_auth_flow`