[BUG] Desktop: "+ New" worktree session fails with "WorktreeCreate hook failed: path contains control characters" (repo not under a TCC-protected folder)

Summary

Starting a new session from the Desktop app's "+ New" screen with the "Worktree" checkbox enabled fails every time with:

WorktreeCreate hook failed: path contains control characters

This appears before the project's own WorktreeCreate hook script ever runs — the configured hook is bash scripts/setup-worktree.sh 2>&1 || true, which always exits 0, so it cannot itself produce this message. No directory is created under .claude/worktrees/, so the failure happens at path/name validation time, before mkdir/hook invocation.

Environment

• Claude.app (Desktop) 1.30096.5
• Embedded Claude Code runtime: 2.1.229 (~/Library/Application Support/Claude/claude-code/2.1.229)
• macOS, Darwin 25.5.0 (arm64)
• Repo path: ~/source/github.com/org/repo-name — NOT under ~/Desktop, ~/Documents, or any other TCC-protected folder
• .claude/settings.json has a WorktreeCreate hook configured:

``json
"hooks": {
"WorktreeCreate": [{"hooks": [{"type": "command", "command": "bash scripts/setup-worktree.sh 2>&1 || true", ...}]}]
}
``

Steps to reproduce

1. Open Claude Code Desktop, "+ New" session screen
2. Select repo repo-name, branch main
3. Check the "Worktree" checkbox
4. Leave the task/question input empty
5. Start the session

Result

An error card appears immediately:

WorktreeCreate hook failed: path contains control characters

Reproduced twice, byte-identical result both times.

Why this doesn't look like a hook/script problem

• The configured hook command always exits 0 (|| true), so it cannot itself throw this validation error.
• No new directory appears under .claude/worktrees/ after the failure, so the failure happens before the app attempts to create/populate the worktree directory.
• The task/question field was empty, so no user-typed text should have fed into whatever name/path is being generated (the app appears to auto-generate a worktree name similar to existing ones in this repo, e.g. elegant-jepsen-2ccd85).

Possibly related

#82691 describes a different-but-adjacent regression in the same "+ New" → WorktreeCreate flow since Desktop 2.1.217, though with a distinct error signature (git/getcwd() EPERM under TCC-protected folders like ~/Desktop/~/Documents). This repo is not in a TCC-protected location, and the error text here is different ("path contains control characters" vs. the git EPERM message), so this may be a separate bug in the same code path rather than the same root cause — flagging the connection in case it's useful for triage.

Ask

• What string is being validated here (worktree name? full path? branch name?), and why would it contain a control character when auto-generated with no user input?
• Is there a way to surface/log the exact rejected string client-side, to help pin down the source?