Team agents stuck on onboarding screen ("Choose text style") instead of entering agent mode

Description

When spawning a teammate agent via the Agent tool with team_name parameter, the spawned agent process gets stuck on the Claude Code onboarding screen ("Choose the text style that looks best with your terminal") and never enters agent mode. The agent cannot respond to shutdown requests and must be force-killed.

Steps to Reproduce

1. Create a team via TeamCreate
2. Spawn a teammate via the Agent tool with team_name and name parameters
3. The spawned CLI process shows the onboarding wizard instead of starting agent work

Expected Behavior

Team agents spawned via the Agent tool should bypass the onboarding screen entirely (similar to how --dangerously-skip-permissions bypasses permission prompts) and immediately enter agent mode to process their assigned tasks.

Actual Behavior

The spawned agent process displays:

Welcome to Claude Code v2.1.75

Let's get started.

Choose the text style that looks best with your terminal
To change this later, run /theme
> 1. Dark mode ✓
  2. Light mode
  3. Dark mode (colorblind-friendly)
  ...

The agent is stuck waiting for interactive input that will never come. It cannot:

• Read its task from the task list
• Respond to shutdown_request messages
• Be cleaned up via TeamDelete (reports "active member")

CLI Command Generated

cd /path/to/project && env CLAUDECODE=1 CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 \
  /Users/.../.local/share/claude/versions/2.1.75 \
  --agent-id lead@vbw-plan-02 \
  --agent-name lead \
  --team-name vbw-plan-02 \
  --agent-color blue \
  --parent-session-id <session-id> \
  --agent-type vbw:vbw-lead \
  --dangerously-skip-permissions \
  --model opus

Environment

• Claude Code version: 2.1.75
• OS: macOS (Darwin 25.3.0)
• Shell: zsh
• Terminal: tmux (team agents spawn in tmux panes)

Workaround

Write plans/artifacts directly as the orchestrator agent instead of delegating to a team Lead agent. The team spawning mechanism is the only affected path — single-agent subagents via Task tool without team_name may work fine.

Impact

This completely blocks the multi-agent team workflow. Any plugin or workflow that relies on TeamCreate + Agent with team_name to spawn teammates cannot function. Each failed spawn leaves orphaned tmux panes that must be manually cleaned up.

Suggested Fix

The CLI should detect when it's running in agent mode (presence of --agent-id, --team-name, or CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1) and skip the onboarding wizard automatically, similar to how --dangerously-skip-permissions works for permission prompts.