fix(security): enforce Tess MCP server identity (#717)

apps/gateway/src/mcp/mcp.controller.ts

@@ -3,7 +3,11 @@ import { Logger } from '@nestjs/common';
 import { fromNodeHeaders } from 'better-auth/node';
 import type { Auth } from '@mosaicstack/auth';
 import type { NestFastifyApplication } from '@nestjs/platform-fastify';
-import type { McpService } from './mcp.service.js';
+import {
+  createMcpActorContext,
+  deriveMcpToolScopesForUser,
+  type McpService,
+} from './mcp.service.js';
 import { AUTH } from '../auth/auth.tokens.js';
 
 /**
@@ -67,14 +71,25 @@ async function handleMcpRequest(
     return;
   }
 
-  const userId = result.user.id;
+  const authUser = result.user as {
+    id: string;
+    role?: string | null;
+    tenantId?: string | null;
+    organizationId?: string | null;
+  };
+  const actor = createMcpActorContext({
+    userId: authUser.id,
+    role: authUser.role,
+    tenantId: authUser.tenantId ?? authUser.organizationId ?? undefined,
+    scopes: deriveMcpToolScopesForUser({ role: authUser.role }),
+  });
 
   // ─── Session routing ─────────────────────────────────────────────────────
   const sessionId = req.raw.headers['mcp-session-id'];
 
   if (typeof sessionId === 'string' && sessionId.length > 0) {
     // Existing session request
-    const transport = mcpService.getSession(sessionId);
+    const transport = mcpService.getSession(sessionId, actor);
     if (!transport) {
       logger.warn(`MCP session not found: ${sessionId}`);
       reply.raw.writeHead(404, { 'Content-Type': 'application/json' });
@@ -112,8 +127,10 @@ async function handleMcpRequest(
   }
 
   // Create new session and handle this initializing request
-  const { transport } = mcpService.createSession(userId);
-  logger.log(`New MCP session created for user ${userId}`);
+  const { transport } = mcpService.createSession(actor);
+  logger.log(
+    `New MCP session created for actor=${actor.userId} tenant=${actor.tenantId} correlation=${actor.correlationId}`,
+  );
 
   await transport.handleRequest(req.raw, reply.raw, body);
 }