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Remove the deprecated RFC7523OAuthClientProvider (#3169)

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Max
2026-07-25 22:50:57 +01:00
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parent 1963af52cc
commit 7163d8263f
5 changed files with 38 additions and 319 deletions
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docs/migration.md
+27
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@@ -1920,6 +1920,33 @@ The WebSocket transport has been removed: `mcp.client.websocket.websocket_client
## OAuth and server auth
### `RFC7523OAuthClientProvider` and `JWTParameters` removed
`RFC7523OAuthClientProvider` (deprecated since 1.23.0) and its `JWTParameters` model have been
removed from `mcp.client.auth.extensions.client_credentials`. The provider implemented the
[RFC 7523](https://datatracker.ietf.org/doc/html/rfc7523) §2.1 `jwt-bearer` *authorization grant*
with an SDK-minted or prebuilt JWT, which no MCP auth extension specifies. Replace it with the
purpose-built provider for the flow you actually run:
- Machine-to-machine with a client secret
([`io.modelcontextprotocol/oauth-client-credentials`](https://modelcontextprotocol.io/extensions/auth/oauth-client-credentials)):
`ClientCredentialsOAuthProvider(server_url=..., storage=..., client_id=..., client_secret=...)`.
- Machine-to-machine authenticating with a JWT instead of a secret (same extension, RFC 7523 §2.2
`private_key_jwt` client authentication on the `client_credentials` grant, which is the mode the
extension actually specifies for JWTs): `PrivateKeyJWTOAuthProvider(server_url=...,
storage=..., client_id=..., assertion_provider=...)`. Build the assertion with
`SignedJWTParameters(issuer=..., subject=..., signing_key=...).create_assertion_provider()`
(replaces `JWTParameters` signing fields), or wrap a prebuilt JWT with
`static_assertion_provider(token)` (replaces `JWTParameters(assertion=...)`).
- Presenting an enterprise ID-JAG under the `jwt-bearer` grant
([SEP-990](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/990)):
`IdentityAssertionOAuthProvider` in `mcp.client.auth.extensions.identity_assertion`.
The provider's third mode — the interactive `authorization_code` flow with `private_key_jwt`
client authentication on the token exchange — has no replacement and is intentionally dropped; it
was never exercised by the test suite and no MCP auth extension specifies it. If you depended on
it, open an issue describing the deployment.
### OAuth metadata URLs no longer gain a trailing slash
`OAuthMetadata`, `ProtectedResourceMetadata`, and `OAuthClientMetadata` now set
src/mcp/client/auth/extensions/client_credentials.py
+2 -155
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@@ -4,11 +4,9 @@ Provides OAuth providers for machine-to-machine authentication flows:
- ClientCredentialsOAuthProvider: For client_credentials with client_id + client_secret
- PrivateKeyJWTOAuthProvider: For client_credentials with private_key_jwt authentication
(typically using a pre-built JWT from workload identity federation)
- RFC7523OAuthClientProvider: For jwt-bearer grant (RFC 7523 Section 2.1)
"""
import time
import warnings
from collections.abc import Awaitable, Callable
from typing import Any, Literal
from uuid import uuid4
@@ -17,9 +15,8 @@ import httpx2
import jwt
from pydantic import BaseModel, Field
from mcp.client.auth import OAuthClientProvider, OAuthFlowError, OAuthTokenError, TokenStorage
from mcp.shared.auth import AuthorizationCodeResult, OAuthClientInformationFull, OAuthClientMetadata
from mcp.shared.exceptions import MCPDeprecationWarning
from mcp.client.auth import OAuthClientProvider, OAuthFlowError, TokenStorage
from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata
class ClientCredentialsOAuthProvider(OAuthClientProvider):
@@ -334,153 +331,3 @@ class PrivateKeyJWTOAuthProvider(OAuthClientProvider):
token_url = self._get_token_endpoint()
return httpx2.Request("POST", token_url, data=token_data, headers=headers)
class JWTParameters(BaseModel):
"""JWT parameters."""
assertion: str | None = Field(
default=None,
description="JWT assertion for JWT authentication. "
"Will be used instead of generating a new assertion if provided.",
)
issuer: str | None = Field(default=None, description="Issuer for JWT assertions.")
subject: str | None = Field(default=None, description="Subject identifier for JWT assertions.")
audience: str | None = Field(default=None, description="Audience for JWT assertions.")
claims: dict[str, Any] | None = Field(default=None, description="Additional claims for JWT assertions.")
jwt_signing_algorithm: str | None = Field(default="RS256", description="Algorithm for signing JWT assertions.")
jwt_signing_key: str | None = Field(default=None, description="Private key for JWT signing.")
jwt_lifetime_seconds: int = Field(default=300, description="Lifetime of generated JWT in seconds.")
def to_assertion(self, with_audience_fallback: str | None = None) -> str:
if self.assertion is not None:
# Prebuilt JWT (e.g. acquired out-of-band)
assertion = self.assertion
else:
if not self.jwt_signing_key:
raise OAuthFlowError("Missing signing key for JWT bearer grant") # pragma: no cover
if not self.issuer:
raise OAuthFlowError("Missing issuer for JWT bearer grant") # pragma: no cover
if not self.subject:
raise OAuthFlowError("Missing subject for JWT bearer grant") # pragma: no cover
audience = self.audience if self.audience else with_audience_fallback
if not audience:
raise OAuthFlowError("Missing audience for JWT bearer grant") # pragma: no cover
now = int(time.time())
claims: dict[str, Any] = {
"iss": self.issuer,
"sub": self.subject,
"aud": audience,
"exp": now + self.jwt_lifetime_seconds,
"iat": now,
"jti": str(uuid4()),
}
claims.update(self.claims or {})
assertion = jwt.encode(
claims,
self.jwt_signing_key,
algorithm=self.jwt_signing_algorithm or "RS256",
)
return assertion
class RFC7523OAuthClientProvider(OAuthClientProvider):
"""OAuth client provider for RFC 7523 jwt-bearer grant.
.. deprecated::
Use :class:`ClientCredentialsOAuthProvider` for client_credentials with
client_id + client_secret, or :class:`PrivateKeyJWTOAuthProvider` for
client_credentials with private_key_jwt authentication instead.
This provider supports the jwt-bearer authorization grant (RFC 7523 Section 2.1)
where the JWT itself is the authorization grant.
"""
def __init__(
self,
server_url: str,
client_metadata: OAuthClientMetadata,
storage: TokenStorage,
redirect_handler: Callable[[str], Awaitable[None]] | None = None,
callback_handler: Callable[[], Awaitable[AuthorizationCodeResult]] | None = None,
timeout: float = 300.0,
jwt_parameters: JWTParameters | None = None,
) -> None:
warnings.warn(
"RFC7523OAuthClientProvider is deprecated. Use ClientCredentialsOAuthProvider "
"or PrivateKeyJWTOAuthProvider instead.",
MCPDeprecationWarning,
stacklevel=2,
)
super().__init__(server_url, client_metadata, storage, redirect_handler, callback_handler, timeout)
self.jwt_parameters = jwt_parameters
async def _exchange_token_authorization_code(
self, auth_code: str, code_verifier: str, *, token_data: dict[str, Any] | None = None
) -> httpx2.Request: # pragma: no cover
"""Build token exchange request for authorization_code flow."""
token_data = token_data or {}
if self.context.client_metadata.token_endpoint_auth_method == "private_key_jwt":
self._add_client_authentication_jwt(token_data=token_data)
return await super()._exchange_token_authorization_code(auth_code, code_verifier, token_data=token_data)
async def _perform_authorization(self) -> httpx2.Request: # pragma: no cover
"""Perform the authorization flow."""
if "urn:ietf:params:oauth:grant-type:jwt-bearer" in self.context.client_metadata.grant_types:
token_request = await self._exchange_token_jwt_bearer()
return token_request
else:
return await super()._perform_authorization()
def _add_client_authentication_jwt(self, *, token_data: dict[str, Any]): # pragma: no cover
"""Add JWT assertion for client authentication to token endpoint parameters."""
if not self.jwt_parameters:
raise OAuthTokenError("Missing JWT parameters for private_key_jwt flow")
if not self.context.oauth_metadata:
raise OAuthTokenError("Missing OAuth metadata for private_key_jwt flow")
# We need to set the audience to the issuer identifier of the authorization server
# https://datatracker.ietf.org/doc/html/draft-ietf-oauth-rfc7523bis-01#name-updates-to-rfc-7523
issuer = str(self.context.oauth_metadata.issuer)
assertion = self.jwt_parameters.to_assertion(with_audience_fallback=issuer)
# When using private_key_jwt, in a client_credentials flow, we use RFC 7523 Section 2.2
token_data["client_assertion"] = assertion
token_data["client_assertion_type"] = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"
# We need to set the audience to the resource server, the audience is different from the one in claims
# it represents the resource server that will validate the token
token_data["audience"] = self.context.get_resource_url()
async def _exchange_token_jwt_bearer(self) -> httpx2.Request:
"""Build token exchange request for JWT bearer grant."""
if not self.context.client_info:
raise OAuthFlowError("Missing client info") # pragma: no cover
if not self.jwt_parameters:
raise OAuthFlowError("Missing JWT parameters") # pragma: no cover
if not self.context.oauth_metadata:
raise OAuthTokenError("Missing OAuth metadata") # pragma: no cover
# We need to set the audience to the issuer identifier of the authorization server
# https://datatracker.ietf.org/doc/html/draft-ietf-oauth-rfc7523bis-01#name-updates-to-rfc-7523
issuer = str(self.context.oauth_metadata.issuer)
assertion = self.jwt_parameters.to_assertion(with_audience_fallback=issuer)
token_data = {
"grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
"assertion": assertion,
}
if self.context.should_include_resource_param(self.context.protocol_version): # pragma: no branch
token_data["resource"] = self.context.get_resource_url()
if self.context.client_metadata.scope: # pragma: no branch
token_data["scope"] = self.context.client_metadata.scope
token_url = self._get_token_endpoint()
return httpx2.Request(
"POST", token_url, data=token_data, headers={"Content-Type": "application/x-www-form-urlencoded"}
)
src/mcp/client/auth/oauth2.py
+8 -13
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@@ -383,9 +383,7 @@ class OAuthClientProvider(httpx2.Auth):
token_url = urljoin(auth_base_url, "/token")
return token_url
async def _exchange_token_authorization_code(
self, auth_code: str, code_verifier: str, *, token_data: dict[str, Any] | None = {}
) -> httpx2.Request:
async def _exchange_token_authorization_code(self, auth_code: str, code_verifier: str) -> httpx2.Request:
"""Build token exchange request for authorization_code flow."""
if self.context.client_metadata.redirect_uris is None:
raise OAuthFlowError("No redirect URIs provided for authorization code grant") # pragma: no cover
@@ -393,16 +391,13 @@ class OAuthClientProvider(httpx2.Auth):
raise OAuthFlowError("Missing client info") # pragma: no cover
token_url = self._get_token_endpoint()
token_data = token_data or {}
token_data.update(
{
"grant_type": "authorization_code",
"code": auth_code,
"redirect_uri": str(self.context.client_metadata.redirect_uris[0]),
"client_id": self.context.client_info.client_id,
"code_verifier": code_verifier,
}
)
token_data: dict[str, Any] = {
"grant_type": "authorization_code",
"code": auth_code,
"redirect_uri": str(self.context.client_metadata.redirect_uris[0]),
"client_id": self.context.client_info.client_id,
"code_verifier": code_verifier,
}
# Only include resource param if conditions are met
if self.context.should_include_resource_param(self.context.protocol_version):
tests/client/auth/extensions/test_client_credentials.py
+1 -139
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@@ -1,26 +1,20 @@
import urllib.parse
import warnings
import jwt
import pytest
from pydantic import AnyHttpUrl, AnyUrl
from pydantic import AnyHttpUrl
from mcp.client.auth.extensions.client_credentials import (
ClientCredentialsOAuthProvider,
JWTParameters,
PrivateKeyJWTOAuthProvider,
RFC7523OAuthClientProvider,
SignedJWTParameters,
static_assertion_provider,
)
from mcp.shared.auth import (
AuthorizationCodeResult,
OAuthClientInformationFull,
OAuthClientMetadata,
OAuthMetadata,
OAuthToken,
)
from mcp.shared.exceptions import MCPDeprecationWarning
class MockTokenStorage:
@@ -48,138 +42,6 @@ def mock_storage():
return MockTokenStorage()
@pytest.fixture
def client_metadata():
return OAuthClientMetadata(
client_name="Test Client",
client_uri=AnyHttpUrl("https://example.com"),
redirect_uris=[AnyUrl("http://localhost:3030/callback")],
scope="read write",
)
@pytest.fixture
def rfc7523_oauth_provider(client_metadata: OAuthClientMetadata, mock_storage: MockTokenStorage):
async def redirect_handler(url: str) -> None: # pragma: no cover
"""Mock redirect handler."""
pass
async def callback_handler() -> AuthorizationCodeResult: # pragma: no cover
"""Mock callback handler."""
return AuthorizationCodeResult(code="test_auth_code", state="test_state")
with warnings.catch_warnings():
warnings.simplefilter("ignore", MCPDeprecationWarning)
return RFC7523OAuthClientProvider(
server_url="https://api.example.com/v1/mcp",
client_metadata=client_metadata,
storage=mock_storage,
redirect_handler=redirect_handler,
callback_handler=callback_handler,
)
class TestOAuthFlowClientCredentials:
"""Test OAuth flow behavior for client credentials flows."""
@pytest.mark.anyio
async def test_token_exchange_request_jwt_predefined(self, rfc7523_oauth_provider: RFC7523OAuthClientProvider):
"""Test token exchange request building with a predefined JWT assertion."""
# Set up required context
rfc7523_oauth_provider.context.client_info = OAuthClientInformationFull(
grant_types=["urn:ietf:params:oauth:grant-type:jwt-bearer"],
token_endpoint_auth_method="private_key_jwt",
redirect_uris=None,
scope="read write",
)
rfc7523_oauth_provider.context.oauth_metadata = OAuthMetadata(
issuer=AnyHttpUrl("https://api.example.com"),
authorization_endpoint=AnyHttpUrl("https://api.example.com/authorize"),
token_endpoint=AnyHttpUrl("https://api.example.com/token"),
registration_endpoint=AnyHttpUrl("https://api.example.com/register"),
)
rfc7523_oauth_provider.context.client_metadata = rfc7523_oauth_provider.context.client_info
rfc7523_oauth_provider.context.protocol_version = "2025-06-18"
rfc7523_oauth_provider.jwt_parameters = JWTParameters(
# https://www.jwt.io
assertion="eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.KMUFsIDTnFmyG3nMiGM6H9FNFUROf3wh7SmqJp-QV30"
)
request = await rfc7523_oauth_provider._exchange_token_jwt_bearer()
assert request.method == "POST"
assert str(request.url) == "https://api.example.com/token"
assert request.headers["Content-Type"] == "application/x-www-form-urlencoded"
# Check form data
content = urllib.parse.unquote_plus(request.content.decode())
assert "grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer" in content
assert "scope=read write" in content
assert "resource=https://api.example.com/v1/mcp" in content
assert (
"assertion=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.KMUFsIDTnFmyG3nMiGM6H9FNFUROf3wh7SmqJp-QV30"
in content
)
@pytest.mark.anyio
async def test_token_exchange_request_jwt(self, rfc7523_oauth_provider: RFC7523OAuthClientProvider):
"""Test token exchange request building wiith a generated JWT assertion."""
# Set up required context
rfc7523_oauth_provider.context.client_info = OAuthClientInformationFull(
grant_types=["urn:ietf:params:oauth:grant-type:jwt-bearer"],
token_endpoint_auth_method="private_key_jwt",
redirect_uris=None,
scope="read write",
)
rfc7523_oauth_provider.context.oauth_metadata = OAuthMetadata(
issuer=AnyHttpUrl("https://api.example.com"),
authorization_endpoint=AnyHttpUrl("https://api.example.com/authorize"),
token_endpoint=AnyHttpUrl("https://api.example.com/token"),
registration_endpoint=AnyHttpUrl("https://api.example.com/register"),
)
rfc7523_oauth_provider.context.client_metadata = rfc7523_oauth_provider.context.client_info
rfc7523_oauth_provider.context.protocol_version = "2025-06-18"
rfc7523_oauth_provider.jwt_parameters = JWTParameters(
issuer="foo",
subject="1234567890",
claims={
"name": "John Doe",
"admin": True,
"iat": 1516239022,
},
jwt_signing_algorithm="HS256",
jwt_signing_key="a-string-secret-at-least-256-bits-long",
jwt_lifetime_seconds=300,
)
request = await rfc7523_oauth_provider._exchange_token_jwt_bearer()
assert request.method == "POST"
assert str(request.url) == "https://api.example.com/token"
assert request.headers["Content-Type"] == "application/x-www-form-urlencoded"
# Check form data
content = urllib.parse.unquote_plus(request.content.decode()).split("&")
assert "grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer" in content
assert "scope=read write" in content
assert "resource=https://api.example.com/v1/mcp" in content
# Check assertion
assertion = next(param for param in content if param.startswith("assertion="))[len("assertion=") :]
claims = jwt.decode(
assertion,
key="a-string-secret-at-least-256-bits-long",
algorithms=["HS256"],
audience="https://api.example.com/",
subject="1234567890",
issuer="foo",
verify=True,
)
assert claims["name"] == "John Doe"
assert claims["admin"]
assert claims["iat"] == 1516239022
class TestClientCredentialsOAuthProvider:
"""Test ClientCredentialsOAuthProvider."""
tests/docs_src/test_oauth_clients.py
-12
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@@ -10,11 +10,9 @@ from docs_src.oauth_clients import tutorial001, tutorial002
from mcp.client.auth import OAuthClientProvider, OAuthFlowError, OAuthRegistrationError, OAuthTokenError, TokenStorage
from mcp.client.auth.extensions.client_credentials import (
PrivateKeyJWTOAuthProvider,
RFC7523OAuthClientProvider,
static_assertion_provider,
)
from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata, OAuthToken
from mcp.shared.exceptions import MCPDeprecationWarning
# See test_index.py for why this is a per-module mark and not a conftest hook.
pytestmark = [pytest.mark.anyio, pytest.mark.filterwarnings("error::mcp.MCPDeprecationWarning")]
@@ -104,16 +102,6 @@ async def test_the_one_more_provider_is_private_key_jwt() -> None:
assert provider.context.client_metadata.token_endpoint_auth_method == "private_key_jwt"
async def test_the_page_does_not_count_the_deprecated_provider() -> None:
"""Why the `!!! info` says *one* more provider: `RFC7523OAuthClientProvider` warns on construction."""
with pytest.warns(MCPDeprecationWarning, match="RFC7523OAuthClientProvider is deprecated"):
RFC7523OAuthClientProvider(
server_url="http://localhost:8001/mcp",
client_metadata=tutorial001.oauth.context.client_metadata,
storage=tutorial001.InMemoryTokenStorage(),
)
async def test_every_oauth_error_is_an_oauth_flow_error() -> None:
"""Catch `OAuthFlowError` and you have caught registration and token failures too."""
assert issubclass(OAuthRegistrationError, OAuthFlowError)