What is UserPromptSubmit?

A hook that runs a Node.js script whenever you submit a prompt, before the coding agent receives it.

Running the bundled user-prompt-submit script on each submitted prompt.

It allows submitted prompts to be processed automatically before the agent starts working.

UserPromptSubmit — Hook for Claude Code by langchain-ai

About the project

langchain-ai/langsmith-claude-code-plugins is a set of Claude Code plugins that sends conversations, tool calls, subagent runs, and context-compaction events to LangSmith, a service for tracing and inspecting agent activity. It is for developers who want to observe and debug Claude Code workflows. The catalogue entries provide hooks, commands, and plugins for adding this tracing workflow to Claude Code.

langchain-ai/langsmith-claude-code-plugins · 73 stars · on GitHub · langchain.com

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/langsmith-claude-code-plugins

Claude Code

/plugin install langsmith-gateway

Made for: Claude Code.

Or install langsmith-gateway, the plugin that ships this one along with the rest of its 3 commands, 3 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.

README.md

[![agentmods](https://agentmods.dev/badge/hooks/langchain-ai/langsmith-claude-code-plugins/user-prompt-submit/github.svg)](https://agentmods.dev/hooks/langchain-ai/langsmith-claude-code-plugins/user-prompt-submit)

Your own site

<a href="https://agentmods.dev/hooks/langchain-ai/langsmith-claude-code-plugins/user-prompt-submit"><img src="https://agentmods.dev/badge/hooks/langchain-ai/langsmith-claude-code-plugins/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.

Your own site · 80×15

<a href="https://agentmods.dev/hooks/langchain-ai/langsmith-claude-code-plugins/user-prompt-submit"><img src="https://agentmods.dev/badge/hooks/langchain-ai/langsmith-claude-code-plugins/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 100% copy Near-identical to another mod 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 2d 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

This is a copy

100% identical to UserPromptSubmit — 4 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/langsmith-gateway/hooks/hooks.json · 13 lines

What it actually says

{
  "UserPromptSubmit": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "exec \"${CLAUDE_PLUGIN_ROOT}/hooks/langsmith-claude-launcher\"\nnode \"${CLAUDE_PLUGIN_ROOT}/bundle/gateway.js\" --plugin gateway",
          "timeout": 60
        }
      ]
    }
  ]
}

Same file

What else `hooks.json` configures

This page is one entry in a file that holds 3. 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.

2d ago Changed 4a1fc711b119
12d ago Changed 831878672afb
1mo ago Changed 29177526b5ab
1mo ago Changed b45099e9e468
2mo 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/langsmith-claude-code-plugins (73 stars, last pushed yesterday), 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. It is 100% identical to UserPromptSubmit, differing in 4 lines, and is treated as a copy.

Claude Code claude-code-plugin langsmith

UserPromptSubmit next to 6 hooks from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
UserPromptSubmitlangchain-ai/langsmith-claude-code-plugins	Hook	73	yesterday	MIT	A	—	Claude Code
Stoptractorjuice/arckit-claude	Hook	6	4d ago	none	A	—	Claude Code
CwdChangedNova-Violet-Role/RoT-MoE	Hook	2	1mo ago	AGPL-3.0	A	—	Claude Code
Notificationprime-radiant-inc/claude-plugin-cxdb-integration	Hook	5	5mo ago	none	A	—	Claude Code
Stopspeson/not-my-reforge	Hook	2	8mo ago	none	A	—	Claude Code
UserPromptSubmitzircote-plugins/tone-police	Hook	1	8mo ago	none	A	—	Claude Code
PostToolUsesupabase/supabase	Hook	115k	yesterday	Apache-2.0	A	—	Claude Code

UserPromptSubmit