Best PromptsClaude Code Hooks Template
The two highest-value Claude Code hooks: auto-format every file the agent edits, and hard-block edits to paths that must never be touched.
{
"hooks": {
"PostToolUse": [
{
"matcher": "Edit|Write",
"hooks": [
{
"type": "command",
"command": "jq -r '.tool_input.file_path // empty' | xargs -r npx prettier --write --ignore-unknown"
}
]
}
],
"PreToolUse": [
{
"matcher": "Edit|Write|Bash",
"hooks": [
{
"type": "command",
"command": "jq -r '.tool_input | tostring' | grep -qE '\.env|migrations/|\.git/' && { echo 'Blocked by hook: this touches a protected path (.env, migrations/, .git). Ask the user before modifying these.' >&2; exit 2; } || exit 0"
}
]
}
]
}
}How to use
Merge the hooks block into .claude/settings.json in your repo (or ~/.claude/settings.json globally). How it works: each hook shells out with the tool call's JSON on stdin, the PostToolUse hook extracts the edited file path and runs Prettier on it (swap in your formatter), and the PreToolUse hook greps the tool input for protected paths and exits with code 2, which blocks the action and feeds the stderr message back to Claude as guidance. Edit the grep pattern to your own protected paths, and verify your setup with the /hooks command. Hooks are deterministic where CLAUDE.md is advisory. Use them for the rules that must never be broken.
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