fix(agent): decode JWT directly to get userId for system prompt

req.user is never populated in agent-service (Kong verifies JWT, no Passport strategy).
This caused userId to always be undefined → system prompt had no 'Current User ID' →
Claude used tenant slug 'shenzhengj' as userId → DB error 'invalid input syntax for
type uuid'.

Fix: decode JWT payload from Authorization header (no signature verify needed — Kong
already verified it) to extract sub (user UUID) for both AgentController and
VoiceSessionController.

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

packages/services/agent-service/src/interfaces/rest/controllers/agent.controller.ts

@@ -139,9 +139,11 @@ export class AgentController {
       this.logger.log(`[Task ${task.id}] Resuming SDK session: ${resumeSessionId}`);
     }
 
-    // Build system prompt with user context so iAgent knows who it's serving
-    const userId: string | undefined = req.user?.sub ?? req.user?.userId;
-    const userEmail: string | undefined = req.user?.email;
+    // Build system prompt with user context so iAgent knows who it's serving.
+    // Kong already verifies the JWT — just decode the payload (no signature check needed).
+    const jwtPayload = this.decodeJwt(req.headers?.['authorization'] as string | undefined);
+    const userId: string | undefined = jwtPayload?.sub ?? req.user?.sub ?? req.user?.userId;
+    const userEmail: string | undefined = jwtPayload?.email ?? req.user?.email;
     const systemPrompt = body.systemPrompt || this.systemPromptBuilder.build({
       tenantId,
       userId,
@@ -788,6 +790,17 @@ export class AgentController {
     });
   }
 
+  /** Decode JWT payload without verifying signature (Kong already verified it). */
+  private decodeJwt(authHeader: string | undefined): Record<string, any> | null {
+    if (!authHeader?.startsWith('Bearer ')) return null;
+    try {
+      const payload = authHeader.slice(7).split('.')[1];
+      return JSON.parse(Buffer.from(payload, 'base64url').toString('utf8'));
+    } catch {
+      return null;
+    }
+  }
+
   private createNewSession(
     tenantId: string,
     engineType: string,

packages/services/agent-service/src/interfaces/rest/controllers/voice-session.controller.ts

@@ -82,10 +82,11 @@ export class VoiceSessionController {
     // so Claude can call the DingTalk OAuth trigger endpoint with the correct session.
     const sessionId = session?.id ?? crypto.randomUUID();
 
-    // Extract user identity from JWT for context-aware system prompt
+    // Extract user identity — decode JWT directly (Kong already verified the signature).
+    const jwtPayload = this.decodeJwt((req as any).headers?.['authorization']);
     const jwtUser = (req as any).user;
-    const userId: string | undefined = jwtUser?.sub ?? jwtUser?.userId;
-    const userEmail: string | undefined = jwtUser?.email;
+    const userId: string | undefined = jwtPayload?.sub ?? jwtUser?.sub ?? jwtUser?.userId;
+    const userEmail: string | undefined = jwtPayload?.email ?? jwtUser?.email;
 
     // Build the full iAgent system prompt (includes DingTalk binding instructions, userId, etc.)
     // If the caller explicitly overrides with their own systemPrompt, use that instead.
@@ -306,4 +307,15 @@ export class VoiceSessionController {
 
     return { triggered: true, instanceId: body.instanceId, instanceName };
   }
+
+  /** Decode JWT payload without verifying signature (Kong already verified it). */
+  private decodeJwt(authHeader: string | undefined): Record<string, any> | null {
+    if (!authHeader?.startsWith('Bearer ')) return null;
+    try {
+      const payload = authHeader.slice(7).split('.')[1];
+      return JSON.parse(Buffer.from(payload, 'base64url').toString('utf8'));
+    } catch {
+      return null;
+    }
+  }
 }