[BUG] claude-code opens a new Terminal.app window on every session start, independent of terminal emulator

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?

Environment

• OS: macOS (Darwin 25.5.0), M1
• Shell: zsh (oh-my-zsh)

Behavior

Every time a claude CLI session is started, a brand-new Terminal.app window opens
within a few seconds — immediately on launch, before any prompt is submitted or tool
is used. This happens regardless of Terminal.app's own settings (startup behavior,
session restore, profile "Run command"), ruling those out as the cause.

What's been ruled out

• No claude shell alias/function in .zshrc/.zshenv/.bash_profile
• Terminal.app: "On startup, open" is a plain new window with the Basic profile

(irrelevant here since Terminal.app isn't the app being launched from)

• Terminal.app Basic profile has no custom "Run command" on the Shell tab
• No SessionStart/Notification hooks configured in ~/.claude/settings.json or

project .claude/settings.json (only unrelated PreToolUse hooks)

• No LaunchAgents referencing claude or Terminal
• No active cron/scheduled jobs

What Should Happen?

No new terminal window should open on session start, regardless of which terminal
emulator is running claude.

Error Messages/Logs

Steps to Reproduce

Traced via ps: started a claude session inside a zsh shell. 7 seconds later, a
new Terminal.app process appeared (fresh PID, PPID=1, i.e. launched via Launch
Services — consistent with an open -a Terminal or
osascript ... tell application "Terminal" call, since GUI app launches via
Launch Services always reparent to launchd regardless of the calling process).

# claude session start
93542   26852  Mon Aug 10 08:52:07 2026   claude

# 7 seconds later, a new Terminal.app process appears
93651       1  Mon Aug 10 08:52:14 2026   /System/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.220 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_