test(ingestion): /mcp's JWT validator and resource_metadata; narrow comments

PR #183 review (comment 15474):
- TestBuildMuxAnswers503ToAJWTOnMCPWhileTheIssuerIsUnresolved: building
  /mcp's middleware with a nil validator turns it red.
- TestBuildMuxMCP401CarriesResourceMetadataInWWWAuthenticate: building it
  with resourceMetadataURL "" turns it red.
- main.go, routes.go and the testMux comment now say exactly what is
  untested: main's restAuth fields and public map passed to buildMux, and
  ListenAndServe (hyperguild#182). Stale public-route list in the
  TestBuildMuxDoesNotWrapPublicRoutes comment corrected.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ingestion/cmd/server/jwt_validator_test.go

@@ -81,3 +81,31 @@ func TestBuildMuxAnswers503ToAJWTWhileTheIssuerIsUnresolved(t *testing.T) {
 	code, _ := do(t, mux, "GET", "/pending", "Bearer aaa.bbb.ccc")
 	assert.Equal(t, http.StatusServiceUnavailable, code)
 }
+
+// PR #183 review: /mcp shares REST's bearer, but only the static token was
+// asserted on it. With the issuer unresolved, a JWT on /mcp answers 503 too,
+// so /mcp's middleware was built with the JWT validator.
+func TestBuildMuxAnswers503ToAJWTOnMCPWhileTheIssuerIsUnresolved(t *testing.T) {
+	srv, _ := fakeIssuer(t, 1000)
+	v, err := buildJWTValidator(context.Background(), slog.New(slog.DiscardHandler), srv.URL, "brain")
+	require.NoError(t, err)
+	mux, err := buildMux(restAuth{token: routesTok, validator: v, realm: "brain"}, testHandler(t),
+		okHandler("mcp"), metrics.New(), nil)
+	require.NoError(t, err)
+	code, _ := do(t, mux, "POST", "/mcp", "Bearer aaa.bbb.ccc")
+	assert.Equal(t, http.StatusServiceUnavailable, code)
+}
+
+// PR #183 review: a 401 on /mcp names the protected-resource metadata in
+// WWW-Authenticate (what the claude.ai OAuth connector discovers from), so
+// /mcp's middleware was built with resourceMetadataURL.
+func TestBuildMuxMCP401CarriesResourceMetadataInWWWAuthenticate(t *testing.T) {
+	const rm = "https://brain.example/.well-known/oauth-protected-resource"
+	mux, err := buildMux(restAuth{token: routesTok, realm: "brain", resourceMetadataURL: rm}, testHandler(t),
+		okHandler("mcp"), metrics.New(), nil)
+	require.NoError(t, err)
+	rec := httptest.NewRecorder()
+	mux.ServeHTTP(rec, httptest.NewRequest(http.MethodPost, "/mcp", nil))
+	require.Equal(t, http.StatusUnauthorized, rec.Code)
+	assert.Contains(t, rec.Header().Get("WWW-Authenticate"), `resource_metadata="`+rm+`"`)
+}

ingestion/cmd/server/main.go

@@ -587,8 +587,10 @@ func main() {
 	//
 	// The whole router, /mcp's bearer included, is built in buildMux so its
 	// tests are tests of production wiring (PR #152 review, hyperguild#154).
-	// The REST API's credential is the same as /mcp's. ListenAndServe below
+	// The REST API's credential is the same as /mcp's. Untested here: the
-	// must serve its result unchanged: that one line is the untested part.
+	// restAuth fields and the public map this call passes in (e.g. a nil
+	// validator would drop JWT auth on /mcp and REST and the suite stays
+	// green), and ListenAndServe serving the result unchanged (hyperguild#182).
 	handler, err := buildMux(restAuth{token: mcpToken, validator: jwtValidator, realm: "brain",
 		resourceMetadataURL: resourceMetadataURL}, h, mcpSrv, metrics.New(), public)
 	if err != nil {

ingestion/cmd/server/routes.go

@@ -41,8 +41,9 @@ type restAuth struct {
 // wrapped in reg's middleware. Other public handlers are registered as given,
 // and only for patterns on the publicRoutes allowlist. It returns an
 // http.Handler, not the *ServeMux, so nothing can register a route on the
-// result. What stays untested is main's own line: a handler main built around
+// result. What stays untested is main's call site: the restAuth fields and
-// this one before ListenAndServe would not be seen by these tests.
+// the public map main passes in, and ListenAndServe serving this handler
+// unchanged (hyperguild#182). The tests build their own arguments.
 func buildMux(
 	auth restAuth, h *api.Handler, mcpHandler http.Handler, reg *metrics.Registry, public map[string]http.Handler,
 ) (http.Handler, error) {

ingestion/cmd/server/routes_test.go

@@ -22,11 +22,13 @@ func okHandler(body string) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) { _, _ = w.Write([]byte(body)) })
 }
 
-// testMux builds the router exactly as main does: buildMux with the full
+// testMux builds the router through buildMux, the function main calls, with
-// public set main registers (stub handlers), a stub MCP server, and real
+// every allowlisted public pattern (stub handlers), a stub MCP server and a
-// bearer config. hyperguild#149: the REST API is authenticated as a whole;
+// static token only: no JWT validator and no resourceMetadataURL (the tests
-// the PR #152 review showed a test of a COPY of the router let main.go
+// in jwt_validator_test.go pass those). It does not use main's own restAuth
-// regress unseen.
+// or public map (hyperguild#182). hyperguild#149: the REST API is
+// authenticated as a whole; the PR #152 review showed a test of a COPY of
+// the router let main.go regress unseen.
 func testMux(t *testing.T) http.Handler {
 	t.Helper()
 	mux, _ := testMuxAndRegistry(t)
@@ -87,8 +89,9 @@ func TestBuildMuxAuthenticatesAnUnregisteredPath(t *testing.T) {
 }
 
 // buildMux registers public handlers as given, without adding auth: each
-// public route owns its own (bearer on /mcp, HMAC on the webhook, client
+// public route owns its own (bearer/JWT on /capture, HMAC on the webhook,
-// secret on /oauth/token) or is meant to be open (/metrics, OAuth metadata).
+// client secret on /oauth/token) or is meant to be open (OAuth metadata).
+// /mcp and /metrics are not public routes: buildMux builds them itself.
 func TestBuildMuxDoesNotWrapPublicRoutes(t *testing.T) {
 	r := testMux(t)
 	for p := range publicRoutes {