Review caught the stated invariant being false. Next splits the matched
suffix on literal `/` before decoding each piece, so a segment can be empty
(`api//mcp`) and a single segment can carry a decoded slash (`api%2Fmcp`).
Neither reaches the allowlist — both fail closed — but the comment claimed
an invariant the router does not provide.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The pattern in the walkthrough was written from memory and differs from the
one on the `shared-memory-mcp` provider in a way that matters: `…:[0-9]+/.*`
requires a path component, so it fails to match a bare
`http://localhost:5693`, which the deployed `…:\d+(/.*)?$` accepts. Copy the
live value verbatim instead.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Two separate discovery footguns, both found while debugging an Authentik
"Redirect URI Error" on a claude.ai custom connector.
RFC 9728 §3.1 puts the metadata for a resource identified by
`https://host/api/mcp` at `/.well-known/oauth-protected-resource/api/mcp`.
Only the root form was served, so clients that derive the metadata URL from
the MCP endpoint URL — rather than reading `resource_metadata` off our 401 —
got Next.js's HTML 404 and failed discovery with a JSON parse error.
Add a `[...path]` route serving the same document with `resource` naming the
suffixed identifier (§3.3 has the client compare it as an exact string, so
echoing the bare origin would be rejected). The document body moves to
`lib/auth/resource-metadata.ts` so the two routes cannot drift apart on
`scopes_supported` — a divergence there costs you the `aud` claim or the
refresh token. Paths are allowlisted rather than wildcarded so this cannot
advertise resources the app does not serve. `buildWwwAuthenticate()` still
points at the root URL; this change is purely additive.
Separately, the redirect URIs an MCP provider needs depend on how clients
reach it: a loopback URI for the CLI, `https://claude.ai/api/mcp/auth_callback`
for a claude.ai custom connector. Registering only the former is what produces
the "Redirect URI Error" page, and a portless `http://localhost/callback`
entry matches nothing the CLI sends. Document both, keyed on the literal
error text, and note that DCR is enterprise-gated on Authentik so these are
hand-registered on a FOSS instance.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
shadowdaoandClaude Opus 5