Plan mode freezes after approval until second instance is opened

Description

After approving a plan in plan mode, Claude Code freezes completely. The process only resumes when a second Claude Code instance is opened in another terminal tab.

Steps to Reproduce

1. Start a conversation in Claude Code
2. Enter plan mode and let Claude create a plan
3. Approve the plan
4. Optionally compact/clear context

Expected: Claude continues executing the plan after approval.
Actual: The terminal hangs indefinitely. No output, no progress.

1. Open a new terminal tab and start another Claude Code instance
2. The first (frozen) instance suddenly resumes and continues working on the plan

Additional Context

• The ExitPlanMode tool sometimes reports the plan as "rejected" even though the user approved it. This happened 2x in a row.
• Possibly related to an IPC or terminal event issue where the first process is blocked waiting for a signal that only arrives when a second process starts.
• macOS (Darwin 25.3.0), zsh shell
• Claude Code version: latest as of 2026-03-12

Workaround

Avoid using the built-in plan mode. Instead, ask Claude to output the plan as regular text and then instruct it to proceed.