diff --git a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py index 9923c3ce4bf..37b7050fceb 100644 --- a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py +++ b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py @@ -411,6 +411,15 @@ class MCPServerManager: aws_role_name=server_config.get("aws_role_name", None), aws_session_name=server_config.get("aws_session_name", None), instructions=server_config.get("instructions", None), + # Token Exchange (OBO) fields + token_exchange_endpoint=server_config.get( + "token_exchange_endpoint", None + ), + audience=server_config.get("audience", None), + subject_token_type=server_config.get( + "subject_token_type", + "urn:ietf:params:oauth:token-type:access_token", + ), ) self._assign_unique_short_prefix(new_server) self.config_mcp_servers[server_id] = new_server @@ -765,6 +774,21 @@ class MCPServerManager: aws_role_name=aws_creds.get("aws_role_name"), aws_session_name=aws_creds.get("aws_session_name"), instructions=mcp_server.instructions, + # Token Exchange (OBO) fields — read from credentials JSON blob + token_exchange_endpoint=( + credentials_dict.get("token_exchange_endpoint") + if credentials_dict + else None + ), + audience=( + credentials_dict.get("audience") if credentials_dict else None + ), + subject_token_type=( + credentials_dict.get("subject_token_type") + if credentials_dict + else None + ) + or "urn:ietf:params:oauth:token-type:access_token", ) return new_server @@ -1136,6 +1160,27 @@ class MCPServerManager: ######################################################### # Methods that call the upstream MCP servers ######################################################### + @staticmethod + def _extract_bearer_token( + oauth2_headers: Optional[Dict[str, str]], + raw_headers: Optional[Dict[str, str]], + ) -> Optional[str]: + """Extract the bare Bearer token from oauth2_headers or raw_headers. + + Returns the token string without the ``Bearer `` prefix, or ``None`` + if no Authorization header is found. + """ + auth_value: Optional[str] = None + if oauth2_headers and "Authorization" in oauth2_headers: + auth_value = oauth2_headers["Authorization"] + elif raw_headers: + # raw_headers may have lowercase keys depending on the ASGI server + normalized = {k.lower(): v for k, v in raw_headers.items()} + auth_value = normalized.get("authorization") + if auth_value and auth_value.startswith("Bearer "): + return auth_value[len("Bearer "):] + return auth_value + def _build_stdio_env( self, server: MCPServer, @@ -1169,25 +1214,30 @@ class MCPServerManager: mcp_auth_header: Optional[Union[str, Dict[str, str]]] = None, extra_headers: Optional[Dict[str, str]] = None, stdio_env: Optional[Dict[str, str]] = None, + subject_token: Optional[str] = None, ) -> MCPClient: """ Create an MCPClient instance for the given server. Auth resolution (single place for all auth logic): 1. ``mcp_auth_header`` — per-request/per-user override - 2. OAuth2 client_credentials token — auto-fetched and cached - 3. ``server.authentication_token`` — static token from config/DB + 2. OAuth2 Token Exchange (OBO) — exchange user token for scoped token + 3. OAuth2 client_credentials token — auto-fetched and cached + 4. ``server.authentication_token`` — static token from config/DB Args: server: The server configuration. mcp_auth_header: Optional per-request auth override. extra_headers: Additional headers to forward. stdio_env: Environment variables for stdio transport. + subject_token: Optional user JWT for token exchange (OBO) flow. Returns: Configured MCP client instance. """ - auth_value = await resolve_mcp_auth(server, mcp_auth_header) + auth_value = await resolve_mcp_auth( + server, mcp_auth_header, subject_token=subject_token + ) transport = server.transport or MCPTransport.sse @@ -2534,9 +2584,12 @@ class MCPServerManager: if server_auth_header is None: server_auth_header = mcp_auth_header - # oauth2 headers + # Extract subject token for OAuth2 Token Exchange (OBO) flow + subject_token: Optional[str] = None extra_headers: Optional[Dict[str, str]] = None - if mcp_server.auth_type == MCPAuth.oauth2: + if mcp_server.auth_type == MCPAuth.oauth2_token_exchange: + subject_token = self._extract_bearer_token(oauth2_headers, raw_headers) + elif mcp_server.auth_type == MCPAuth.oauth2: if mcp_server.has_client_credentials: # For M2M OAuth servers, Authorization must come from token fetch. extra_headers = None @@ -2604,6 +2657,7 @@ class MCPServerManager: mcp_auth_header=server_auth_header, extra_headers=extra_headers, stdio_env=stdio_env, + subject_token=subject_token, ) call_tool_params = MCPCallToolRequestParams(