Haiku agents approve shutdown_request but don't terminate

Description

When using agent teams with haiku-model teammates, agents approve shutdown_request messages but don't actually terminate. They stay in an idle state indefinitely, wasting team slots and blocking wave transitions.

Steps to Reproduce

1. Create a team with TeamCreate
2. Spawn a teammate with model: "haiku"
3. Agent completes its task and goes idle
4. Send shutdown_request via SendMessage
5. Agent responds with shutdown_approved
6. Agent remains idle — does not terminate

Expected Behavior

Agent should terminate after approving the shutdown request.

Actual Behavior

Agent approves the shutdown but stays alive in idle state. Multiple shutdown requests produce multiple approvals with no termination. Even direct text messages saying "please shut down" are acknowledged but not acted on.

Observations

• Sonnet-model agents generally handle shutdown correctly
• Haiku agents consistently exhibit this behavior
• The agent appears to process the message but doesn't execute the actual termination step
• Workaround: accept the zombie agent and clean up via TeamDelete at end of wave

Environment

• Claude Code CLI
• Team-based workflow with 4-7 agents per wave
• Haiku used for lightweight roles (committer, documenter)

🤖 Generated with Claude Code