Add lockdown mode support for HTTP server (#1876)

* add readonly and toolset support

* address feedback

* forgotten files

* remove redundant checks in WithRequestConfig

* move middleware in RegisterRoutes

* improve comment and add TestParseCommaSeparated

* fix broken TestInventoryFiltersForRequest

* parse X-MCP-Tools into ctx

* clean up TestInventoryFiltersForRequest

* review http args and add lockdown ctx helpers

* parse lockdown header and update GetFlags to retrieve ff from ctx

* clean up and fix tests

* fix GetFlags check, move lockdown parsing in WithRequestConfig and fix broken tests

Author: kerobbi

cmd/github-mcp-server/main.go

@@ -96,6 +96,7 @@ var (
 		Short: "Start HTTP server",
 		Long:  `Start an HTTP server that listens for MCP requests over HTTP.`,
 		RunE: func(_ *cobra.Command, _ []string) error {
+			ttl := viper.GetDuration("repo-access-cache-ttl")
 			httpConfig := ghhttp.HTTPServerConfig{
 				Version:              version,
 				Host:                 viper.GetString("host"),
@@ -104,6 +105,8 @@ var (
 				EnableCommandLogging: viper.GetBool("enable-command-logging"),
 				LogFilePath:          viper.GetString("log-file"),
 				ContentWindowSize:    viper.GetInt("content-window-size"),
+				LockdownMode:         viper.GetBool("lockdown-mode"),
+				RepoAccessCacheTTL:   &ttl,
 			}
 
 			return ghhttp.RunHTTPServer(httpConfig)

pkg/context/request.go

@@ -49,3 +49,19 @@ func GetTools(ctx context.Context) []string {
 	}
 	return nil
 }
+
+// lockdownCtxKey is a context key for lockdown mode
+type lockdownCtxKey struct{}
+
+// WithLockdownMode adds lockdown mode state to the context
+func WithLockdownMode(ctx context.Context, enabled bool) context.Context {
+	return context.WithValue(ctx, lockdownCtxKey{}, enabled)
+}
+
+// IsLockdownMode retrieves the lockdown mode state from the context
+func IsLockdownMode(ctx context.Context) bool {
+	if enabled, ok := ctx.Value(lockdownCtxKey{}).(bool); ok {
+		return enabled
+	}
+	return false
+}

pkg/github/dependencies.go

@@ -87,7 +87,7 @@ type ToolDependencies interface {
 	GetT() translations.TranslationHelperFunc
 
 	// GetFlags returns feature flags
-	GetFlags() FeatureFlags
+	GetFlags(ctx context.Context) FeatureFlags
 
 	// GetContentWindowSize returns the content window size for log truncation
 	GetContentWindowSize() int
@@ -165,7 +165,7 @@ func (d BaseDeps) GetRepoAccessCache(_ context.Context) (*lockdown.RepoAccessCac
 func (d BaseDeps) GetT() translations.TranslationHelperFunc { return d.T }
 
 // GetFlags implements ToolDependencies.
-func (d BaseDeps) GetFlags() FeatureFlags { return d.Flags }
+func (d BaseDeps) GetFlags(_ context.Context) FeatureFlags { return d.Flags }
 
 // GetContentWindowSize implements ToolDependencies.
 func (d BaseDeps) GetContentWindowSize() int { return d.ContentWindowSize }
@@ -262,7 +262,6 @@ func NewRequestDeps(
 	lockdownMode bool,
 	repoAccessOpts []lockdown.RepoAccessOption,
 	t translations.TranslationHelperFunc,
-	flags FeatureFlags,
 	contentWindowSize int,
 	featureChecker inventory.FeatureFlagChecker,
 ) *RequestDeps {
@@ -272,7 +271,6 @@ func NewRequestDeps(
 		lockdownMode:      lockdownMode,
 		RepoAccessOpts:    repoAccessOpts,
 		T:                 t,
-		Flags:             flags,
 		ContentWindowSize: contentWindowSize,
 		featureChecker:    featureChecker,
 	}
@@ -379,7 +377,11 @@ func (d *RequestDeps) GetRepoAccessCache(ctx context.Context) (*lockdown.RepoAcc
 func (d *RequestDeps) GetT() translations.TranslationHelperFunc { return d.T }
 
 // GetFlags implements ToolDependencies.
-func (d *RequestDeps) GetFlags() FeatureFlags { return d.Flags }
+func (d *RequestDeps) GetFlags(ctx context.Context) FeatureFlags {
+	return FeatureFlags{
+		LockdownMode: d.lockdownMode && ghcontext.IsLockdownMode(ctx),
+	}
+}
 
 // GetContentWindowSize implements ToolDependencies.
 func (d *RequestDeps) GetContentWindowSize() int { return d.ContentWindowSize }

pkg/github/feature_flags_test.go

@@ -45,7 +45,7 @@ func HelloWorldTool(t translations.TranslationHelperFunc) inventory.ServerTool {
 			if deps.IsFeatureEnabled(ctx, RemoteMCPEnthusiasticGreeting) {
 				greeting += " Welcome to the future of MCP! 🎉"
 			}
-			if deps.GetFlags().InsiderMode {
+			if deps.GetFlags(ctx).InsiderMode {
 				greeting += " Experimental features are enabled! 🚀"
 			}
 

pkg/github/issues.go

@@ -334,7 +334,7 @@ func GetIssue(ctx context.Context, client *github.Client, deps ToolDependencies,
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	flags := deps.GetFlags()
+	flags := deps.GetFlags(ctx)
 
 	issue, resp, err := client.Issues.Get(ctx, owner, repo, issueNumber)
 	if err != nil {
@@ -389,7 +389,7 @@ func GetIssueComments(ctx context.Context, client *github.Client, deps ToolDepen
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	flags := deps.GetFlags()
+	flags := deps.GetFlags(ctx)
 
 	opts := &github.IssueListCommentsOptions{
 		ListOptions: github.ListOptions{
@@ -449,7 +449,7 @@ func GetSubIssues(ctx context.Context, client *github.Client, deps ToolDependenc
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	featureFlags := deps.GetFlags()
+	featureFlags := deps.GetFlags(ctx)
 
 	opts := &github.IssueListOptions{
 		ListOptions: github.ListOptions{

pkg/github/pullrequests.go

@@ -139,7 +139,7 @@ func GetPullRequest(ctx context.Context, client *github.Client, deps ToolDepende
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	ff := deps.GetFlags()
+	ff := deps.GetFlags(ctx)
 
 	pr, resp, err := client.PullRequests.Get(ctx, owner, repo, pullNumber)
 	if err != nil {
@@ -350,7 +350,7 @@ func GetPullRequestReviewComments(ctx context.Context, gqlClient *githubv4.Clien
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	ff := deps.GetFlags()
+	ff := deps.GetFlags(ctx)
 
 	// Convert pagination parameters to GraphQL format
 	gqlParams, err := pagination.ToGraphQLParams()
@@ -437,7 +437,7 @@ func GetPullRequestReviews(ctx context.Context, client *github.Client, deps Tool
 	if err != nil {
 		return nil, fmt.Errorf("failed to get repo access cache: %w", err)
 	}
-	ff := deps.GetFlags()
+	ff := deps.GetFlags(ctx)
 
 	reviews, resp, err := client.PullRequests.ListReviews(ctx, owner, repo, pullNumber, nil)
 	if err != nil {

pkg/github/server_test.go

@@ -56,7 +56,7 @@ func (s stubDeps) GetRepoAccessCache(ctx context.Context) (*lockdown.RepoAccessC
 	return s.repoAccessCache, nil
 }
 func (s stubDeps) GetT() translations.TranslationHelperFunc          { return s.t }
-func (s stubDeps) GetFlags() FeatureFlags                            { return s.flags }
+func (s stubDeps) GetFlags(ctx context.Context) FeatureFlags         { return s.flags }
 func (s stubDeps) GetContentWindowSize() int                         { return s.contentWindowSize }
 func (s stubDeps) IsFeatureEnabled(_ context.Context, _ string) bool { return false }
 

pkg/http/headers/headers.go

@@ -32,6 +32,8 @@ const (
 	MCPToolsetsHeader = "X-MCP-Toolsets"
 	// MCPToolsHeader is a comma-separated list of MCP tools that the request is for.
 	MCPToolsHeader = "X-MCP-Tools"
+	// MCPLockdownHeader indicates whether lockdown mode is enabled.
+	MCPLockdownHeader = "X-MCP-Lockdown"
 	// MCPFeaturesHeader is a comma-separated list of feature flags to enable.
 	MCPFeaturesHeader = "X-MCP-Features"
 )

pkg/http/middleware/request_config.go

@@ -26,6 +26,10 @@ func WithRequestConfig(next http.Handler) http.Handler {
 			ctx = ghcontext.WithTools(ctx, tools)
 		}
 
+		if relaxedParseBool(r.Header.Get(headers.MCPLockdownHeader)) {
+			ctx = ghcontext.WithLockdownMode(ctx, true)
+		}
+
 		next.ServeHTTP(w, r.WithContext(ctx))
 	})
 }

pkg/http/server.go

@@ -89,9 +89,6 @@ func RunHTTPServer(cfg HTTPServerConfig) error {
 		cfg.LockdownMode,
 		repoAccessOpts,
 		t,
-		github.FeatureFlags{
-			LockdownMode: cfg.LockdownMode,
-		},
 		cfg.ContentWindowSize,
 		nil,
 	)