UserPromptSubmit

UserPromptSubmit is a hook for Claude Code from langchain-ai/skills-benchmarks. Its token cost is not measured, scanned A, original, MIT.

A prompt-submit hook is a script that runs when you send a prompt, before the coding agent receives it.

In plain words
What is it for?
It is for executing the configured Node.js user-prompt-submit script whenever a prompt is submitted.
Why use it?
It provides a point where the prompt can be handled or prepared before the agent starts working.

Hook for Claude Code ✓ vendor

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 langsmith-tracing plugin — 9 hooks shipped together

One of 9 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 8 are separate, each on its own page.

Good fit It is for executing the configured Node.js user-prompt-submit script whenever a prompt is submitted.

Compare 6 hooks from other repositories ↓
About the project

skills-benchmarks is a test suite that measures how the design of skill documentation affects Claude Code's adherence to recommended coding patterns. It is used to compare documentation approaches across LangChain-related tasks and other agent workflows. Its catalogue entries represent skills, hooks, instructions, and a plugin used in the benchmark project.

langchain-ai/skills-benchmarks · 116 stars · on GitHub

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 langchain-ai/skills-benchmarks
Claude Code
/plugin install langsmith-tracing

Made for: Claude Code.

Or install langsmith-tracing, the plugin that ships this one along with the rest of its 9 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 UserPromptSubmit

README.md
[![agentmods](https://agentmods.dev/badge/hooks/langchain-ai/skills-benchmarks/user-prompt-submit/github.svg)](https://agentmods.dev/hooks/langchain-ai/skills-benchmarks/user-prompt-submit)
Your own site
<a href="https://agentmods.dev/hooks/langchain-ai/skills-benchmarks/user-prompt-submit"><img src="https://agentmods.dev/badge/hooks/langchain-ai/skills-benchmarks/user-prompt-submit/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 UserPromptSubmit

Your own site · 80×15
<a href="https://agentmods.dev/hooks/langchain-ai/skills-benchmarks/user-prompt-submit"><img src="https://agentmods.dev/badge/hooks/langchain-ai/skills-benchmarks/user-prompt-submit.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

UserPromptSubmit 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 9d 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:

scaffold/plugins/langsmith-tracing/hooks/hooks.json · 13 lines

What it actually says

{
  "UserPromptSubmit": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "node \"${CLAUDE_PLUGIN_ROOT}/bundle/user-prompt-submit.js\"",
          "timeout": 30
        }
      ]
    }
  ]
}
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. 9d ago First seen · 13 lines scan A 075c6936a642

Subscribe to this mod's changes

UserPromptSubmit is a hook published in the GitHub repository langchain-ai/skills-benchmarks (116 stars, last pushed 21d ago), licensed MIT. 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.