[BUG] <Box> can't be nested inside <Text> crash when permission dialog renders in tmux split-pane spawned agent

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When a sub-agent is spawned via CLAUDE_CODE_SPAWN_BACKEND=tmux with teammateMode: splitPane and permissions are set to ask, the agent crashes immediately with an Ink rendering error when it tries to show the permission prompt dialog.

What Should Happen?

Permission dialog renders and waits for user input.

Error Messages/Logs

Agent crashes with:

ERROR  <Box> can't be nested inside <Text> component
/$bunfs/root/src/entrypoints/cli.js:496:249

Steps to Reproduce

Set CLAUDE_CODE_SPAWN_BACKEND=tmux and teammateMode: splitPane in settings
Set any permission to ask (e.g. Bash(), Read())
Spawn a sub-agent via agent teams — e.g.:

env CLAUDECODE=1 CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 claude \
--agent-id backend-dev@my-team \
--agent-name backend-dev \
--team-name my-team \
--agent-color green \
--parent-session-id <id> \
--model sonnet

Agent triggers any tool that requires the permission prompt

Workaround
Changing "ask" to "allow" in permissions prevents the crash — the permission dialog is never rendered so the Ink error is not triggered.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.118

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

_No response_