feat: forward valid_scopes through KeycloakOAuthProxy for offline_access DCR

🤖 Generated with Claude Code

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

fastmcp_slim/fastmcp/server/auth/providers/keycloak.py

@@ -125,6 +125,7 @@ class KeycloakOAuthProxy(OAuthProxy):
         upstream_client_secret: str | None = None,
         base_url: AnyHttpUrl | str,
         required_scopes: list[str] | str | None = None,
+        valid_scopes: list[str] | str | None = None,
         audience: str | list[str] | None = None,
         token_verifier: TokenVerifier | None = None,
         # Direct endpoint overrides (optional if realm_url is provided)
@@ -148,6 +149,11 @@ class KeycloakOAuthProxy(OAuthProxy):
             upstream_client_secret: Client secret. Optional for public clients.
             base_url: Public URL of this FastMCP server.
             required_scopes: Scopes to require on incoming tokens. Defaults to `["openid"]`.
+            valid_scopes: Scopes advertised to clients via the `/.well-known` endpoints
+                and accepted during Dynamic Client Registration. Defaults to
+                `required_scopes`. Set this to include `offline_access` so clients can
+                register for the long-lived offline refresh tokens this proxy handles
+                without also forcing `offline_access` onto every access token.
             audience: Optional JWT audience for token validation. Recommended for production.
             token_verifier: Custom token verifier. Defaults to a JWTVerifier configured
                 for the Keycloak realm's JWKS endpoint.
@@ -185,6 +191,9 @@ class KeycloakOAuthProxy(OAuthProxy):
         parsed_scopes = (
             parse_scopes(required_scopes) if required_scopes is not None else ["openid"]
         )
+        parsed_valid_scopes = (
+            parse_scopes(valid_scopes) if valid_scopes is not None else None
+        )
 
         if token_verifier is None:
             if realm is None:
@@ -206,6 +215,7 @@ class KeycloakOAuthProxy(OAuthProxy):
             upstream_client_id=upstream_client_id,
             upstream_client_secret=upstream_client_secret,
             token_verifier=token_verifier,
+            valid_scopes=parsed_valid_scopes,
             base_url=base_url,
             jwt_signing_key=jwt_signing_key,
             client_storage=client_storage,

tests/server/auth/oauth_proxy/test_tokens.py

@@ -925,6 +925,49 @@ class TestKeycloakOAuthProxy:
         assert upstream_token_set.refresh_token_never_expires is True
         assert upstream_token_set.refresh_token_expires_at is None
 
+    def test_valid_scopes_forwarded_for_dcr(self, jwt_verifier):
+        """valid_scopes must be advertised/accepted for DCR independently of required_scopes.
+
+        Offline tokens (the whole point of this proxy) require clients to register
+        the `offline_access` scope. Without a separate valid_scopes pass-through,
+        DCR scope validation falls back to required_scopes and rejects it.
+        """
+        proxy = KeycloakOAuthProxy(
+            realm_url="https://keycloak.example.com/realms/test",
+            upstream_client_id="test-client",
+            upstream_client_secret="test-secret",
+            token_verifier=jwt_verifier,
+            valid_scopes=["openid", "offline_access"],
+            base_url="https://proxy.example.com",
+            jwt_signing_key="test-secret-key",
+            client_storage=MemoryStore(),
+        )
+        assert proxy.client_registration_options is not None
+        assert proxy.client_registration_options.valid_scopes == [
+            "openid",
+            "offline_access",
+        ]
+        # required_scopes (token verification) stays independent of valid_scopes (DCR)
+        assert jwt_verifier.required_scopes == ["read", "write"]
+
+    def test_valid_scopes_accepts_string(self, jwt_verifier):
+        """A space/comma-delimited string is parsed like required_scopes."""
+        proxy = KeycloakOAuthProxy(
+            realm_url="https://keycloak.example.com/realms/test",
+            upstream_client_id="test-client",
+            upstream_client_secret="test-secret",
+            token_verifier=jwt_verifier,
+            valid_scopes="openid offline_access",
+            base_url="https://proxy.example.com",
+            jwt_signing_key="test-secret-key",
+            client_storage=MemoryStore(),
+        )
+        assert proxy.client_registration_options is not None
+        assert proxy.client_registration_options.valid_scopes == [
+            "openid",
+            "offline_access",
+        ]
+
     async def test_refresh_expires_in_zero_subsequent_refresh_does_not_shrink(
         self, proxy
     ):