Agent Teams: MCP tool permission requests not surfaced to team lead (tmux mode)

Bug Description

When using agent teams in tmux mode (CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1), permission requests from tmux teammates for MCP tools are never surfaced to the team lead as approval prompts, causing teammates to stall indefinitely. Bash tool permissions work correctly through the same delegation pathway.

Environment

• Claude Code v2.1.79
• Ubuntu 24.04 LTS, tmux 3.4
• Claude Max subscription (Opus 4.6)

Steps to Reproduce

1. Enable agent teams: CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 in settings.json
2. Start Claude Code inside tmux (ensure TMUX env var is set)
3. Create a team with TeamCreate
4. Spawn a tmux teammate with a task that uses an MCP tool not in the permissions.allow list
5. Observe the teammate's tmux pane

Expected Behavior

The MCP tool permission request should appear as an approval prompt in the team lead's session (same as Bash tool permissions), allowing the user to approve or deny.

Actual Behavior

• The teammate's pane shows: "Waiting for team lead approval" with "Permission request sent to team leader"
• The permission request IS correctly written to the team inbox file (~/.claude/teams/{name}/inboxes/team-lead.json) as a permission_request message with the MCP tool name
• But the team lead's Claude Code process never picks it up or shows it to the user
• The teammate stalls indefinitely
• Shutdown requests are also ignored while stalled

Evidence from Inbox Files

All three permission requests were correctly delivered to the team lead's inbox:

// Message 0 - Bash permission (WORKED - surfaced to user, approved)
{"type": "permission_request", "tool_name": "Bash", "request_id": "perm-...-vnwh2p6", ...}

// Message 3 - Bash permission (WORKED - surfaced to user, approved)  
{"type": "permission_request", "tool_name": "Bash", "request_id": "perm-...-ihbz0lw", ...}

// Message 6 - MCP permission (BROKEN - never surfaced to user)
{"type": "permission_request", "tool_name": "mcp__tooluniverse__find_tools", "request_id": "perm-...-dzj6uai", ...}

The Bash permission requests received permission_response messages back. The MCP one never did.

Root Cause Hypothesis

The permission request handler in the team lead's process appears to have a code path that processes Bash tool permission requests but fails to handle MCP tool permission requests (tool names matching mcp__* pattern). The inbox delivery works correctly for both — the issue is in the team lead's reading/processing of the inbox.

Workaround

Pre-approve all MCP tools that teammates will need in settings.json:

{
  "permissions": {
    "allow": [
      "mcp__codex-bridge__*",
      "mcp__biomcp__*"
    ]
  }
}

Additional Notes

• Regular SendMessage between teammates and lead works fine
• shutdown_request / shutdown_response flow works fine
• Only the permission delegation for MCP tools is broken
• If a teammate stalls on permission, it also ignores shutdown requests — the only recovery is killing the tmux pane and manually editing config.json to set "isActive": false before TeamDelete

Labels

agent-teams, bug, mcp