lock-settings

name	lock-settings
description	Add deny rules to protect settings and hook files from Claude Code modification. Run after a feature PR that adds/modifies settings or hooks has been merged.
allowed-tools	[]

Add deny rules (Edit and Write) and sandbox denyWrite entries for settings and hook files that should be locked from Claude Code modification.

• Edit/Write deny rules block Claude's built-in Edit and Write tools.
• Sandbox denyWrite provides OS-level (kernel/Seatbelt) enforcement that blocks Bash subprocesses (sed -i, echo >, rm, etc.) from writing to those files.

Both layers are required for defense-in-depth.

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Step 1 — Identify files to protect

Scan the repository for files that should be protected from Claude Code modification. Start with these known locations, and add any other security-sensitive or configuration files you discover:

• .claude/settings.json
• .claude/settings.local.json
• .claude/hooks/*.sh
• .githooks/*
• scripts/install-hooks.sh

Use your judgement to identify additional files that need protection — for example, CI/CD configs, deployment scripts, or other files where unintended modification could compromise security or break workflows.

Read the current .claude/settings.json to check which files already have deny rules and sandbox.filesystem.denyWrite entries. Only add rules for files that are not yet protected.

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Step 2 — Create a branch and add deny rules

1. Create a new branch named after what is being locked (e.g., chore/lock-hooks-and-settings, chore/lock-ci-configs).
2. Add to .claude/settings.json for each unprotected file:
   • Permission deny rules (under permissions.deny):
     • Edit(<path>) — block the Edit tool
     • Write(<path>) — block the Write tool
   • Sandbox deny rule (under sandbox.filesystem.denyWrite):
     • ./<path> — block Bash-level writes at the OS level
   • Important: List individual files, not directories. Directory-level denyWrite would prevent creating new files in that directory.
3. Commit with message: chore: add deny rules for settings and hook files

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Step 3 — Create the PR

Run /create-pr to push and open a pull request. The PR description should list exactly which files were locked and why.