# Askit Build Hook

> Creates and improves event-driven hooks (Advanced tier) for a plugin to the Advanced Skill Library Standard. Use when you need to add a hook, enforce a guard on a tool or session event, inject context, or document a hook's event, scope, and failure behavior.

- **Type:** Skill
- **Install:** `agentstack add skill-product-on-purpose-agent-skills-toolkit-askit-build-hook`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [product-on-purpose](https://agentstack.voostack.com/s/product-on-purpose)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [product-on-purpose](https://github.com/product-on-purpose)
- **Source:** https://github.com/product-on-purpose/agent-skills-toolkit/tree/main/skills/askit-build-hook
- **Website:** https://product-on-purpose.github.io/agent-skills-toolkit

## Install

```sh
agentstack add skill-product-on-purpose-agent-skills-toolkit-askit-build-hook
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# askit-build-hook

## Purpose
Author a plugin's hooks: event-driven enforcement or context injection (Standard sec 3.5). Hooks are an Advanced-tier capability. Two modes: `create` scaffolds a hook and its registration; `improve` raises an existing hook toward the bar (documentation, idempotency, actionable block messages). The hook SKILL is portable; what it authors is primarily a Claude capability (31 events) with a smaller Codex event set. Authoring depth is in [references/authoring-hooks.md](references/authoring-hooks.md). Follows the shared builder contract ([../../docs/reference/builder-pattern.md](../../docs/reference/builder-pattern.md)).

## When to use
When the user asks to add, scaffold, author, or improve a hook (a PreToolUse / PostToolUse / Stop / SessionStart guard, a context injector, or any event-driven automation) for a plugin.

## create mode
1. Brief interview: the event (for example PreToolUse), the trigger or matcher, the hook type (`command` / `http` / `mcp_tool` / `prompt` / `agent`), the scope (what it guards or injects), and the failure behavior (fail-safe block vs warn). Skip the interview if these are in context.
2. Author the hook and its registration. A plugin registers hooks in `hooks/hooks.json` using `${CLAUDE_PLUGIN_ROOT}`; copy `templates/hooks.json` if none exists. Document the event, trigger, scope, and failure behavior (Standard sec 3.5 MUST).
3. For a blocking hook (for example a PreToolUse deny), write an ACTIONABLE message that states what was blocked and how to proceed. Make the hook idempotent where the event can repeat.
4. Register the hook in `library.json` `components.hooks` as `{ name, version, tier, status }`.
5. Targets: Claude supports 31 events. Codex supports a smaller set (PreToolUse, PostToolUse, Pre/PostCompact, SessionStart, SubagentStart/Stop, UserPromptSubmit, Stop, PermissionRequest). Verify current Codex plugin-hook ingestion at build time (a known caveat) and scope `agent-targets` accordingly.
6. Assess with `node scripts/evaluate.mjs . --json`. Hook documentation and idempotency are graded at the Advanced tier; the deterministic hook check lands with Gold self-hosting (Phase 5).

## improve mode
1. Run `node scripts/evaluate.mjs . --json` and read the report.
2. Fix what it flags. For hooks specifically, confirm the event / trigger / scope / failure are documented (sec 3.5), the block message is actionable, and the hook is idempotent.
3. Re-run to confirm.

## Scope
Hooks are Advanced-tier and the most agent-specific component: Claude's event set is the richest, Codex covers a subset, and the wider ecosystem does not support hooks. A hook MUST document its event, trigger, scope, and failure behavior, and a blocking hook MUST emit an actionable message (Standard sec 3.5). Least privilege applies (sec 9): a hook's command runs with the narrowest scope needed.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [product-on-purpose](https://github.com/product-on-purpose)
- **Source:** [product-on-purpose/agent-skills-toolkit](https://github.com/product-on-purpose/agent-skills-toolkit)
- **License:** Apache-2.0
- **Homepage:** https://product-on-purpose.github.io/agent-skills-toolkit

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-product-on-purpose-agent-skills-toolkit-askit-build-hook
- Seller: https://agentstack.voostack.com/s/product-on-purpose
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.