Agent Teams: Spawned teammates cannot access ToolSearch or deferred tools (MCP)

Bug Description

When using the experimental Agent Teams feature (CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1), spawned agent team members (teammates) do not have access to ToolSearch or any deferred tools. This means they cannot load MCP tools (e.g., mcp__claude-in-chrome__*) even when the agent definition explicitly lists those tools.

Steps to Reproduce

1. Enable Agent Teams: set CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 in ~/.claude/settings.json
2. Define an agent in .claude/agents/tx.md with tools: Bash, Read, Grep, Glob, Edit, Write, WebFetch, Task, ToolSearch
3. Spawn the agent as a teammate using the Task tool with team_name parameter
4. Have the spawned agent attempt to call ToolSearch to load deferred MCP tools (e.g., Chrome automation tools)

Expected Behavior

The spawned teammate should have access to ToolSearch and be able to load deferred tools, consistent with the tools listed in its agent definition.

Actual Behavior

The spawned teammate reports that ToolSearch is not available. Any attempt to use it fails. The tools: header in agent definitions appears to be descriptive only — it does not actually grant access to ToolSearch or deferred tools in the spawned agent's environment.

This was reproduced across 4 separate TX (teammate) instances in the same session, all failing identically.

Impact

This is a significant limitation for Agent Teams workflows that require browser automation or MCP tool access. For example:

• A testing agent (TX) that needs Chrome MCP tools for UI verification cannot function as designed
• Any teammate that needs to discover and load deferred tools is blocked

Workaround

Restructure the team so that only the team lead (LX) — which runs in the main Claude Code session with full tool access — performs tasks requiring deferred/MCP tools. Teammates are limited to non-deferred tools only.

Environment

• Claude Code CLI (latest as of 2026-02-05)
• macOS (Darwin 24.6.0)
• CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 enabled
• MCP tools configured via .mcp.json (Chrome automation via claude-in-chrome)