Will Wilson 2075c8c41c feat(mcp): OAuth 2.1 auth for MCP — connect Claude.ai with your Sure login (#2234) ...

* feat(mcp): add OAuth well-known discovery endpoints (RFC 8414 + RFC 9728)

Serves /.well-known/oauth-protected-resource (RFC 9728) and
/.well-known/oauth-authorization-server (RFC 8414) so MCP clients
can auto-discover the authorization server. Both endpoints are
unauthenticated and respect APP_URL for reverse-proxy deployments.

* feat(mcp): add dynamic client registration endpoint (RFC 7591)

POST /register creates a public Doorkeeper::Application on demand so
MCP clients (e.g. Claude.ai) can self-register without manual setup.
Validates redirect_uris (including blank entries), falls back to
"MCP Client" name, returns no client_secret (public client, PKCE only).
Rate-limited to 10 registrations/min/IP via Rack::Attack.

* feat(mcp): authenticate via Doorkeeper OAuth2, keep MCP_API_TOKEN as fallback

MCP endpoint now accepts OAuth2 Bearer tokens issued by Doorkeeper.
Falls back to the existing MCP_API_TOKEN env-var flow so self-hosted
deployments are not broken. Requires MCP_OAUTH_ENABLED or MCP_API_TOKEN
to be set — the endpoint returns 503 otherwise.

- OauthBase concern provides APP_URL-aware configured_base_url (trailing
  slash stripped to prevent double-slash URLs)
- Bearer scheme parsed case-insensitively (RFC 7235)
- Only read_write scope accepted — read scope would allow mutating tools
  (CreateGoal, ImportBankStatement), so read-only tokens are rejected
- Deactivated users rejected even with a valid Doorkeeper token
- WWW-Authenticate header on 401 points to RFC 9728 resource metadata
- SHA-256 digest used for constant-time env-var comparison
- Rack::Attack throttle added for POST /register
- Routes wired: /.well-known/*, /register, use_doorkeeper

* fix(mcp): disable Turbo on OAuth consent form for external redirect URIs

Turbo was intercepting the authorization form POST and XHR-fetching
the redirect_uri (e.g. https://claude.ai/api/mcp/auth_callback),
which CORS blocks. Extend the existing turbo_disabled guard to cover
any redirect_uri that doesn't originate from the app itself.

* feat(mcp): add Settings::McpController with connected clients view

- Settings > MCP page (under Advanced) shows the MCP server URL with
  copy button and step-by-step instructions for connecting Claude.ai
- Lists active non-mobile OAuth tokens with app name and revoke action;
  mobile device tokens are excluded to prevent accidental disconnection
- Removes the MCP_OAUTH_ENABLED env-var gate — OAuth auth is always
  available since Doorkeeper handles consent; MCP_API_TOKEN remains
  as a self-hosted fallback

* fix(mcp): remove client_credentials from grant_types_supported metadata

Only authorization_code is supported by the registration endpoint.
Advertising client_credentials was misleading — a client that reads
the metadata and attempts that flow would get an application with the
wrong grant type.

2026-06-11 16:19:58 +02:00

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