modelcontextprotocol/inspector
Watch
1
0
Fork
You've already forked inspector
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 2

fix(auth): accept RFC 8414 metadata served at the OIDC well-known path

Browse source 
The SDK's `discoverAuthorizationServerMetadata` picks its validation schema
from the well-known filename that resolved rather than from the document that
came back, so anything found at `/.well-known/openid-configuration` is
validated as an OpenID provider document — requiring `jwks_uri`,
`subject_types_supported` and `id_token_signing_alg_values_supported`, three
fields RFC 8414 does not define. RFC 8414 §5 permits that filename for general
OAuth metadata, so a conforming plain OAuth 2.0 authorization server is
rejected; and because the parse throws instead of continuing the candidate
loop, discovery aborts and the connection fails outright.

Filed upstream as modelcontextprotocol/typescript-sdk#2733.

`core/auth/oidcDiscoveryCompat.ts` works around it without fabricating a
field: on a failed RFC 8414 candidate it probes the OIDC candidates the SDK
would try next and, when one returns a document that satisfies
`OAuthMetadataSchema` but fails the OIDC schema, serves that body as the RFC
8414 response so the SDK picks the schema that describes it. A genuine OpenID
provider document is left to the SDK's own OIDC leg. Issuer validation runs
unchanged, since the substituted document is the one the server published.

It wraps `effectiveAuthFetch` — above the fetch tracker, the opposite of
`withOAuthEndpointOverrides` — so the Network tab still records the real 404
and the real probe rather than the substitution.

The candidate derivation mirrors the SDK's `buildDiscoveryUrls`, which a fetch
wrapper cannot call, and a test pins it against that export so the two cannot
drift.

Adds `oauth.asMetadataPath` to the composable test server (mirroring
`oauth.resourceMetadataPath`) and the `oauth-rfc8414-at-oidc-path-http.json`
showcase config that reproduces the failure.

Closes #2172

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UL9retfvAXRgvi6EWk4SY4
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-28 00:40:11 -04:00
commit 7ca753bc4c
1 changed files with 844 additions and 36 deletions
Download patch file Download diff file Expand all files Collapse all files

12
test-servers/src/test-server-fixtures.ts
View file

@ -2915,6 +2915,13 @@ export function createOAuthTestServerConfig(options: {
* it via `WWW-Authenticate: Bearer resource_metadata="…"` (#2071).
*/
resourceMetadataPath?: string;
/**
* Move the RFC 8414 authorization-server metadata document off the
* well-known path — set it to `/.well-known/openid-configuration` to serve
* plain OAuth 2.0 metadata where the SDK expects an OpenID provider
* document (#2172).
*/
asMetadataPath?: string;
}): Partial<ServerConfig> {
return {
oauth: {
@ -2928,6 +2935,11 @@ export function createOAuthTestServerConfig(options: {
...(options.resourceMetadataPath !== undefined
? { resourceMetadataPath: options.resourceMetadataPath }
: {}),
// Same `!== undefined` reasoning as above: an explicit `""` is invalid
// and must reach the server so it reports the bad fixture.
...(options.asMetadataPath !== undefined
? { asMetadataPath: options.asMetadataPath }
: {}),
staticClients: options.staticClients,
supportDCR: options.supportDCR ?? false,
supportCIMD: options.supportCIMD ?? false,