Handoff: Codebase Agent → Cowork

Created: February 1, 2026 From: Codebase Agent (Cursor/Claude Code - Session 79) To: Cowork Agent (Claude Desktop) Priority: HIGH Type: validation

TL;DR

I've implemented the MCP JSON-RPC controller and handoff tools. Your job: test the custom connector in Claude Desktop and validate everything works.

What I Implemented

1. MCP JSON-RPC Controller

File: apis/backend-ai-api/src/app/mcp-gateway/mcp-jsonrpc.controller.ts

Endpoints:

• POST /ai-api/mcp - Main JSON-RPC endpoint
• POST /ai-api/mcp/jsonrpc - Alternative endpoint
• GET /ai-api/mcp/events - SSE for real-time events

Protocol Methods:

• initialize - Auto-registers Claude Desktop as Cowork agent
• tools/list - Returns all 79+ tools including new handoff tools
• tools/call - Execute any MCP tool
• resources/list - Returns empty (future expansion)
• prompts/list - Returns empty (future expansion)
• ping - Health check

2. Handoff Tools (3 New)

3. Auto-Registration

On initialize, the controller:

1. Extracts client info from headers (User-Agent, X-Client-Info)
2. Generates unique agentId: cowork-{clientName}-{timestamp}
3. Registers in AgentRegistry with capabilities
4. Returns agentId in response for future handoff operations

4. SSE Events

The /mcp/events endpoint:

• Heartbeat every 30 seconds
• Handoff completion events
• Per-agent event streams

Your Testing Tasks

Task 1: Validate Connector Setup

1. Start the backend:

   cd apis/backend-ai-api
   yarn start:dev
   

2. Add custom connector in Claude Desktop:

   • Name: GoGrab AI Test
   • URL: http://localhost:3000/ai-api/mcp

3. Observe:

   • Does Claude Desktop discover tools?
   • Can you see 79+ tools in the tool picker?
   • Any errors in Claude Desktop logs?

Document findings in: session-79/79.1-protocol-validation-results.md

Task 2: Test Tool Execution

Try calling these tools:

1. preflight:

   Call preflight with task: "Test the Claude Desktop connector integration"
   

2. get_stats:

   Call get_stats to verify MCP system status
   

3. check_handoffs:

   Call check_handoffs with your agentId (from initialize response)
   

Task 3: Test Handoff Flow

1. Create a test handoff from Cursor: I'll create a handoff to you using create_handoff.

2. You poll for it: Call check_handoffs - you should see the pending handoff.

3. You accept it: Call accept_handoff with the handoffId.

4. You complete it: Call complete_handoff with a response.

5. Verify notification: I should receive a completion event.

What You Should Report Back

Protocol Compatibility

[ ] Claude Desktop sends standard MCP JSON-RPC
[ ] Tool list loads correctly (79+ tools)
[ ] Tool execution works (preflight, log_decision)
[ ] Agent auto-registration works

Issues Found

<!-- List any errors, mismatches, or problems -->

Recommended Changes

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Handoff for You to Test

I'm creating a test handoff right now. After you connect, call check_handoffs and you should see it.

Handoff Details:

• Type: code-to-browser
• Summary: "Validate Claude Desktop connector integration works end-to-end"
• Tasks:
  1. Connect via custom connector
  2. Verify tool discovery
  3. Execute preflight tool
  4. Check for this handoff
  5. Complete this handoff with findings

Files I Created/Modified

Communication Protocol

If You Find Issues

Create handoff back with:

• What failed
• Error messages
• What you think the fix is

If Everything Works

Create summary with:

• Confirmation all tests passed
• Any edge cases discovered
• Recommended next steps

Success Criteria for This Handoff

• Custom connector connects successfully
• All 79+ tools discoverable
• preflight tool executes correctly
• check_handoffs returns pending handoff
• accept_handoff marks handoff as acknowledged
• complete_handoff marks handoff as completed
• Completion event received (if SSE works)

Handoff created by Codebase Agent Session 79.2 - MCP JSON-RPC Implementation Complete