UserPromptExpansion

UserPromptExpansion is a hook for Claude Code from happyhappy-jun/writing-driven-autoresearch. Its token cost is not measured, scanned A, original, Apache-2.0.

A hook that runs a Python script whenever a user prompt is expanded before the coding agent receives it. A hook is an automatic action attached to a particular event.

In plain words
What is it for?
Use it to trigger usage logging during prompt expansion in Claude Code. It applies to every prompt because its matching rule is "*".
Why use it?
It can record when this prompt-expansion step is used, without requiring a separate manual command. The input only identifies the logging script, not the exact data it records.

Hook for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the alin plugin — 2 skills, 2 hooks shipped together

One of 2 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 1 are separate, each on its own page.

Good fit Use it to trigger usage logging during prompt expansion in Claude Code. It applies to every prompt because its matching rule is "*".

Compare 6 hooks from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add happyhappy-jun/writing-driven-autoresearch
Claude Code
/plugin install alin

Made for: Claude Code.

Or install alin, the plugin that ships this one along with the rest of its 2 skills, 2 hooks.

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 UserPromptExpansion

README.md
[![agentmods](https://agentmods.dev/badge/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion/github.svg)](https://agentmods.dev/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion)
Your own site
<a href="https://agentmods.dev/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion"><img src="https://agentmods.dev/badge/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for UserPromptExpansion

Your own site · 80×15
<a href="https://agentmods.dev/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion"><img src="https://agentmods.dev/badge/hooks/happyhappy-jun/writing-driven-autoresearch/user-prompt-expansion.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

UserPromptExpansion 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 11d ago.

A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

alin-skills/hooks/hooks.json · 13 lines

What it actually says

{
  "UserPromptExpansion": [
    {
      "matcher": "*",
      "hooks": [
        {
          "type": "command",
          "command": "python3 \"${CLAUDE_PLUGIN_ROOT}/hooks/log_skill_usage.py\""
        }
      ]
    }
  ]
}
Same file

What else hooks.json configures

This page is one entry in a file that holds 2. Installing the file brings all of them; each is measured and scanned on its own page.

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. 11d ago First seen · 13 lines scan A 43b067c1099d

Subscribe to this mod's changes

UserPromptExpansion is a hook published in the GitHub repository happyhappy-jun/writing-driven-autoresearch (21 stars, last pushed 1mo ago), licensed Apache-2.0. Its token cost is not measured: a hook is shell that never enters the context. 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 2026-08-30.