fix: correlate upstream discovery events to client requests in console

Fan-out discovery methods (tools/list, prompts/list, resources/list)
used synthetic request IDs that couldn't be looked up in the
correlation map. This caused upstream_response events to have no
correlationId, making the console unable to find upstream content
for replay ("No content to replay").

Fix: pass correlationId through RouteContext → discovery methods →
onUpstreamCall callback, so the handler can use it directly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/mcplocal/src/http/project-mcp-endpoint.ts

@@ -223,9 +223,9 @@ export function registerProjectMcpEndpoint(app: FastifyInstance, mcpdClient: Mcp
     if (trafficCapture) {
       router.onUpstreamCall = (info) => {
         const sid = transport.sessionId ?? 'unknown';
-        // Recover the correlationId from the upstream request's id (preserved from client request)
+        // Prefer correlationId passed by router (fan-out discovery), fall back to request ID lookup
         const reqId = (info.request as { id?: string | number }).id;
-        const corrId = reqId != null ? requestCorrelations.get(reqId) : undefined;
+        const corrId = info.correlationId ?? (reqId != null ? requestCorrelations.get(reqId) : undefined);
         trafficCapture.emit({
           timestamp: new Date().toISOString(),
           projectName,
@@ -269,7 +269,7 @@ export function registerProjectMcpEndpoint(app: FastifyInstance, mcpdClient: Mcp
           correlationId,
         });
 
-        const ctx = transport.sessionId ? { sessionId: transport.sessionId } : undefined;
+        const ctx = transport.sessionId ? { sessionId: transport.sessionId, correlationId } : { correlationId };
         const response = await router.route(message as unknown as JsonRpcRequest, ctx);
 
         // Forward queued notifications BEFORE the response — the response send

src/mcplocal/src/router.ts

@@ -14,6 +14,8 @@ import { pauseQueue } from './proxymodel/pause-queue.js';
 
 export interface RouteContext {
   sessionId?: string;
+  /** Correlation ID for traffic inspection (links upstream calls to client request) */
+  correlationId?: string;
 }
 
 /**
@@ -63,7 +65,7 @@ export class McpRouter {
   private pluginContexts = new Map<string, PluginContextImpl>();
 
   /** Optional callback for traffic inspection — called after each upstream call completes. */
-  onUpstreamCall: ((info: { upstream: string; method?: string; request: unknown; response: unknown; durationMs: number }) => void) | null = null;
+  onUpstreamCall: ((info: { upstream: string; method?: string; request: unknown; response: unknown; durationMs: number; correlationId?: string }) => void) | null = null;
 
   setPaginator(paginator: ResponsePaginator): void {
     this.paginator = paginator;
@@ -247,7 +249,7 @@ export class McpRouter {
   /**
    * Discover tools from all upstreams by calling tools/list on each.
    */
-  async discoverTools(): Promise<Array<{ name: string; description?: string; inputSchema?: unknown }>> {
+  async discoverTools(correlationId?: string): Promise<Array<{ name: string; description?: string; inputSchema?: unknown }>> {
     const allTools: Array<{ name: string; description?: string; inputSchema?: unknown }> = [];
 
     for (const [serverName, upstream] of this.upstreams) {
@@ -262,7 +264,7 @@ export class McpRouter {
           const start = performance.now();
           response = await upstream.send(req);
           const durationMs = Math.round(performance.now() - start);
-          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs });
+          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs, ...(correlationId ? { correlationId } : {}) });
         } else {
           response = await upstream.send(req);
         }
@@ -299,7 +301,7 @@ export class McpRouter {
   /**
    * Discover resources from all upstreams by calling resources/list on each.
    */
-  async discoverResources(): Promise<Array<{ uri: string; name?: string; description?: string; mimeType?: string }>> {
+  async discoverResources(correlationId?: string): Promise<Array<{ uri: string; name?: string; description?: string; mimeType?: string }>> {
     const allResources: Array<{ uri: string; name?: string; description?: string; mimeType?: string }> = [];
 
     for (const [serverName, upstream] of this.upstreams) {
@@ -314,7 +316,7 @@ export class McpRouter {
           const start = performance.now();
           response = await upstream.send(req);
           const durationMs = Math.round(performance.now() - start);
-          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs });
+          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs, ...(correlationId ? { correlationId } : {}) });
         } else {
           response = await upstream.send(req);
         }
@@ -341,7 +343,7 @@ export class McpRouter {
   /**
    * Discover prompts from all upstreams by calling prompts/list on each.
    */
-  async discoverPrompts(): Promise<Array<{ name: string; description?: string; arguments?: unknown[] }>> {
+  async discoverPrompts(correlationId?: string): Promise<Array<{ name: string; description?: string; arguments?: unknown[] }>> {
     const allPrompts: Array<{ name: string; description?: string; arguments?: unknown[] }> = [];
 
     for (const [serverName, upstream] of this.upstreams) {
@@ -356,7 +358,7 @@ export class McpRouter {
           const start = performance.now();
           response = await upstream.send(req);
           const durationMs = Math.round(performance.now() - start);
-          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs });
+          this.onUpstreamCall({ upstream: serverName, method: req.method, request: req, response, durationMs, ...(correlationId ? { correlationId } : {}) });
         } else {
           response = await upstream.send(req);
         }
@@ -483,7 +485,7 @@ export class McpRouter {
       case 'tools/list': {
         if (this.plugin && context?.sessionId) {
           const ctx = await this.getOrCreatePluginContext(context.sessionId);
-          let tools = await this.discoverTools();
+          let tools = await this.discoverTools(context?.correlationId);
 
           if (this.plugin.onToolsList) {
             tools = await this.plugin.onToolsList(tools, ctx);
@@ -493,7 +495,7 @@ export class McpRouter {
         }
 
         // No plugin: return upstream tools only
-        const tools = await this.discoverTools();
+        const tools = await this.discoverTools(context?.correlationId);
         return { jsonrpc: '2.0', id: request.id, result: { tools } };
       }
 
@@ -503,12 +505,12 @@ export class McpRouter {
       case 'resources/list': {
         if (this.plugin?.onResourcesList && context?.sessionId) {
           const ctx = await this.getOrCreatePluginContext(context.sessionId);
-          const resources = await this.discoverResources();
+          const resources = await this.discoverResources(context?.correlationId);
           const filtered = await this.plugin.onResourcesList(resources, ctx);
           return { jsonrpc: '2.0', id: request.id, result: { resources: filtered } };
         }
 
-        const resources = await this.discoverResources();
+        const resources = await this.discoverResources(context?.correlationId);
         // Append mcpctl prompt resources
         const mcpdResources: Array<{ uri: string; name: string; description: string; mimeType: string }> = [];
         if (this.mcpdClient && this.projectName) {
@@ -543,6 +545,7 @@ export class McpRouter {
             request: { jsonrpc: '2.0', id: request.id, method: 'resources/list' },
             response: mcpdResponse,
             durationMs: 0,
+            ...(context?.correlationId ? { correlationId: context.correlationId } : {}),
           });
         }
         return {
@@ -620,12 +623,12 @@ export class McpRouter {
       case 'prompts/list': {
         if (this.plugin?.onPromptsList && context?.sessionId) {
           const ctx = await this.getOrCreatePluginContext(context.sessionId);
-          const upstreamPrompts = await this.discoverPrompts();
+          const upstreamPrompts = await this.discoverPrompts(context?.correlationId);
           const filtered = await this.plugin.onPromptsList(upstreamPrompts, ctx);
           return { jsonrpc: '2.0', id: request.id, result: { prompts: filtered } };
         }
 
-        const upstreamPrompts = await this.discoverPrompts();
+        const upstreamPrompts = await this.discoverPrompts(context?.correlationId);
         // Include mcpctl-managed prompts from mcpd alongside upstream prompts
         const managedIndex = await this.fetchPromptIndex();
         const managedPrompts = managedIndex.map((p) => ({
@@ -641,6 +644,7 @@ export class McpRouter {
             request: { jsonrpc: '2.0', id: request.id, method: 'prompts/list' },
             response: mcpdResponse,
             durationMs: 0,
+            ...(context?.correlationId ? { correlationId: context.correlationId } : {}),
           });
         }
         return {