feat(auth): Support manual PRM override

Author: duwenxin99

cmd/root.go

@@ -124,6 +124,7 @@ func NewCommand(opts *internal.ToolboxOptions) *cobra.Command {
 	flags.BoolVar(&opts.Cfg.DisableReload, "disable-reload", false, "Disables dynamic reloading of tools file.")
 	flags.BoolVar(&opts.Cfg.UI, "ui", false, "Launches the Toolbox UI web server.")
 	flags.StringVar(&opts.Cfg.ToolboxUrl, "toolbox-url", "", "Specifies the Toolbox URL. Used as the resource field in the MCP PRM file when MCP Auth is enabled. Falls back to TOOLBOX_URL environment variable.")
+	flags.StringVar(&opts.Cfg.McpPrmFile, "mcp-prm-file", "", "Path to a manual Protected Resource Metadata (PRM) JSON file. If provided, overrides auto-generation.")
 	// TODO: Insecure by default. Might consider updating this for v1.0.0
 	flags.StringSliceVar(&opts.Cfg.AllowedOrigins, "allowed-origins", []string{"*"}, "Specifies a list of origins permitted to access this server. Defaults to '*'.")
 	flags.StringSliceVar(&opts.Cfg.AllowedHosts, "allowed-hosts", []string{"*"}, "Specifies a list of hosts permitted to access this server. Defaults to '*'.")

internal/server/config.go

@@ -72,6 +72,8 @@ type ServerConfig struct {
 	UI bool
 	// ToolboxUrl specifies the URL to advertise in the MCP PRM file as the resource field.
 	ToolboxUrl string
+	// McpPrmFile specifies the path to a manual Protected Resource Metadata (PRM) JSON file. If provided, overrides auto-generation.
+	McpPrmFile string
 	// Specifies a list of origins permitted to access this server.
 	AllowedOrigins []string
 	// Specifies a list of hosts permitted to access this server.

internal/server/mcp.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"os"
 	"sync"
 	"time"
 
@@ -305,7 +306,7 @@ func mcpRouter(s *Server) (chi.Router, error) {
 		}
 	}
 
-	if mcpAuthEnabled {
+	if mcpAuthEnabled || s.mcpPrmFile != "" {
 		r.Get("/.well-known/oauth-protected-resource", func(w http.ResponseWriter, r *http.Request) { prmHandler(s, w, r) })
 	}
 
@@ -689,6 +690,22 @@ type prmResponse struct {
 
 // prmHandler generates the Protected Resource Metadata (PRM) file for MCP Authorization.
 func prmHandler(s *Server, w http.ResponseWriter, r *http.Request) {
+	if s.mcpPrmFile != "" {
+		prmBytes, err := os.ReadFile(s.mcpPrmFile)
+		if err != nil {
+			s.logger.ErrorContext(r.Context(), "failed to read manual PRM file", "error", err, "path", s.mcpPrmFile)
+			// Returning 500 when it explicitly fails to read a configured file
+			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		if _, err := w.Write(prmBytes); err != nil {
+			s.logger.ErrorContext(r.Context(), "failed to write manual PRM file response", "error", err)
+		}
+		return
+	}
+
 	var servers []string
 	var scopes []string
 	for _, authSvc := range s.ResourceMgr.GetAuthServiceMap() {

internal/server/mcp_test.go

@@ -1247,3 +1247,77 @@ func TestPRMEndpoint(t *testing.T) {
 		t.Errorf("unexpected PRM response: got %+v, want %+v", got, want)
 	}
 }
+
+func TestPRMEndpoint_ManualFile(t *testing.T) {
+	// Create a temporary manual PRM file
+	tmpFile, err := os.CreateTemp("", "manual_prm_*.json")
+	if err != nil {
+		t.Fatalf("failed to create temp file: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	manualPRMContent := []byte(`{
+		"resource": "https://manual.example.com/mcp",
+		"authorization_servers": ["https://manual-auth.example.com"],
+		"scopes_supported": ["manual:scope"],
+		"bearer_methods_supported": ["header"]
+	}`)
+
+	if _, err := tmpFile.Write(manualPRMContent); err != nil {
+		t.Fatalf("failed to write to temp file: %v", err)
+	}
+	tmpFile.Close()
+
+	// Initialize the server with the manual PRM file path
+	resourceManager := resources.NewResourceManager(nil, nil, nil, nil, nil, nil, nil)
+	testLogger, err := log.NewStdLogger(os.Stdout, os.Stderr, "info")
+	if err != nil {
+		t.Fatalf("unable to initialize logger: %s", err)
+	}
+
+	s := &Server{
+		logger:      testLogger,
+		ResourceMgr: resourceManager,
+		mcpPrmFile:  tmpFile.Name(), // Inject manual config path
+	}
+
+	r, err := mcpRouter(s)
+	if err != nil {
+		t.Fatalf("unexpected error creating router: %v", err)
+	}
+
+	ts := httptest.NewServer(r)
+	defer ts.Close()
+
+	// Make the request
+	resp, body, err := runRequest(ts, http.MethodGet, "/.well-known/oauth-protected-resource", nil, nil)
+	if err != nil {
+		t.Fatalf("unexpected error during request: %s", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("expected status %d, got %d", http.StatusOK, resp.StatusCode)
+	}
+	if contentType := resp.Header.Get("Content-Type"); contentType != "application/json" {
+		t.Fatalf("expected content-type application/json, got %s", contentType)
+	}
+
+	// Verify the response body matches the exact contents of the manual file
+	var got map[string]any
+	if err := json.Unmarshal(body, &got); err != nil {
+		t.Fatalf("unexpected error unmarshalling body: %s", err)
+	}
+
+	want := map[string]any{
+		"resource": "https://manual.example.com/mcp",
+		"authorization_servers": []any{
+			"https://manual-auth.example.com",
+		},
+		"scopes_supported":         []any{"manual:scope"},
+		"bearer_methods_supported": []any{"header"},
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("unexpected manual PRM response: got %+v, want %+v", got, want)
+	}
+}

internal/server/server.go

@@ -53,6 +53,7 @@ type Server struct {
 	sseManager      *sseManager
 	ResourceMgr     *resources.ResourceManager
 	toolboxUrl      string
+	mcpPrmFile      string
 }
 
 func InitializeConfigs(ctx context.Context, cfg ServerConfig) (
@@ -380,6 +381,7 @@ func NewServer(ctx context.Context, cfg ServerConfig) (*Server, error) {
 		sseManager:      sseManager,
 		ResourceMgr:     resourceManager,
 		toolboxUrl:      cfg.ToolboxUrl,
+		mcpPrmFile:      cfg.McpPrmFile,
 	}
 
 	// cors