guard

Overview

Safety guardrail that lets users declare protected paths (no edits allowed) or scoped paths (only edits within scope allowed). Integrates with the session to prevent accidental modifications to critical files.

How this differs from other features:

• .claude/rules/ — permanent rules. This skill sets session-scoped guards that can be cleared.
• permissionMode: plan — makes an agent read-only. This skill restricts WHICH files can be edited.

Modes

Protect Mode

Declare files or directories that should NOT be modified:

/guard protect .env prisma/schema.prisma packages/engine/

This creates a guard file that Claude checks before editing:

GUARD_FILE=".context/guard.json"
mkdir -p .context

cat > "$GUARD_FILE" <<EOF
{
  "mode": "protect",
  "protected": [".env", "prisma/schema.prisma", "packages/engine/"],
  "created": "$(date -u +%Y-%m-%dT%H:%M:%SZ)",
  "reason": "User-declared protected paths"
}
EOF

Output:

Guard active — protected paths:
  - .env
  - prisma/schema.prisma
  - packages/engine/**

These paths will be flagged before any edit. Use /guard clear to remove.

Scope Mode

Restrict edits to ONLY the specified directories:

/guard scope src/api/ src/models/

cat > "$GUARD_FILE" <<EOF
{
  "mode": "scope",
  "allowed": ["src/api/", "src/models/"],
  "created": "$(date -u +%Y-%m-%dT%H:%M:%SZ)",
  "reason": "User-declared edit scope"
}
EOF

Output:

Guard active — edits scoped to:
  - src/api/**
  - src/models/**

Files outside this scope will be flagged before any edit. Use /guard clear to remove.

Status Mode

Show current guard state:

/guard status

Read .context/guard.json and display the current guards.

Clear Mode

Remove all guards:

/guard clear

rm -f ".context/guard.json"

How Guards Are Enforced

After creating the guard file, Claude should check it before every file edit:

1. Before using Edit or Write tools, check if .context/guard.json exists
2. If mode: "protect" — verify the target file is NOT in the protected list
3. If mode: "scope" — verify the target file IS within the allowed directories
4. If a guard would be violated, warn the user and ask for confirmation before proceeding