hook-architecture

hook-architecture is a skill for Claude Code, Codex from zircote-plugins/auto-harness. It costs 58 tokens per session (1,843 once invoked), scanned A, original, no licence file.

A guide to the design of automated tests driven by hooks, which are program points that run when specific events happen. It covers topics such as prompt interception, state management, test wrappers, and hook data formats.

In plain words
What is it for?
It is for understanding hook architecture, including UserPromptSubmit events, hook-driven testing, test wrappers, and hook JSON.
Why use it?
It helps explain how these testing hooks fit together, reducing confusion when designing or debugging hook-based automation.

Skill for Claude CodeCodex

Part of the auto-harness plugin — 3 skills, 5 commands, 2 agents, 1 hook shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/zircote-plugins/auto-harness/hook-architecture
Any agent
npx skills add zircote-plugins/auto-harness --skill hook-architecture
Clone the repo
git clone --depth 1 https://github.com/zircote-plugins/auto-harness

Made for: Claude Code, Codex.

Or install auto-harness, the plugin that ships this one along with the rest of its 3 skills, 5 commands, 2 agents, 1 hook.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for hook-architecture

README.md
[![agentmods](https://agentmods.dev/badge/skills/zircote-plugins/auto-harness/hook-architecture.svg)](https://agentmods.dev/skills/zircote-plugins/auto-harness/hook-architecture)
Your own site
<a href="https://agentmods.dev/skills/zircote-plugins/auto-harness/hook-architecture"><img src="https://agentmods.dev/badge/skills/zircote-plugins/auto-harness/hook-architecture.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,843 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00058 $0.01843
Opus 5 $0.00029 $0.00922
Sonnet 5 $0.00012 $0.00369
Haiku 4.5 $0.00006 $0.00184

Measured 4d ago against content hash eb3dd1636988, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

hook-architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/hook-architecture/SKILL.md · 329 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 329 lines · 58 tokens per session scan A eb3dd1636988

Subscribe to this mod's changes

hook-architecture is a skill published in the GitHub repository zircote-plugins/auto-harness (3 stars, last pushed 6mo ago), with no licence file. It adds 58 tokens to every session and 1,843 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.