HOOKS

A guard hook that crashes, times out or points at a missing script lets the tool call through by default in Claude Code. v2.1.295 adds onFailure: block. Here is what each coding agent does when your policy hook breaks, with real test runs.

Claude Code mods are plugins whose JavaScript handlers run inside Claude Code. What they do that hooks and skills cannot, a first mod, and the trust question.

Commercial underwriters drown in PDF submissions. Here is how to build a Claude Agent SDK triage bot with skills, hooks, and a clean audit trail.

Claude Code hooks still install by hand-editing JSON. The Hookyard prototype shows what a hook package manager should look like, from manifest to safe install.

Manufacturing teams ship ladder logic and ESP32 firmware without code review. Here is a Codex CLI setup with hooks that catches the dangerous patterns first.

SessionStart hooks can persist env vars across Bash tool calls.

Event-driven automation with 20+ lifecycle events.

Fire when subagents spawn and finish.

Fire on task lifecycle events.

Fire when settings or CLAUDE.md files change during a session.

Fire before and after context compaction.

Run shell scripts on events with environment variable passing.

Use Claude itself to handle hook logic instead of shell scripts.

Spawn subagents to handle complex hook logic.

Run hooks in the background without blocking the session.