UserPromptSubmit

UserPromptSubmit is a hook for coding agents from evo-hq/evo. Its token cost is not measured, scanned C, a copy of PreToolUse, Apache-2.0.

A prompt-submission hook is an automatic command that runs when you send a prompt, before the coding agent reads it. This one runs a Node.js command from the evo project.

In plain words
What is it for?
Running a command at prompt-submission time, with the hook applying to submitted prompts from the evo setup.
Why use it?
It creates a place to inspect or process prompts before the agent receives them. The provided command is encoded, so its exact behavior is not clear from the description.

Hook

Part of the evo plugin — 7 skills, 2 commands, 3 agents, 6 hooks shipped together

One of 6 entries in hooks.json — they are configured in one file and arrive together.

About the project

Evo is an agent plugin that turns a codebase into an automated experiment loop, discovering metrics, changing code, and testing whether those changes improve the results. It is used to optimize software through parallel subagents, tree-based exploration, shared experiment records, and optional regression or safety gates. The catalogue entries provide agent skills, hooks, commands, and other workflow components for operating Evo.

evo-hq/evo · 1,440 stars · on GitHub

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 hooks/evo-hq/evo/user-prompt-submit
Clone the repo
git clone --depth 1 https://github.com/evo-hq/evo

Or install evo, the plugin that ships this one along with the rest of its 7 skills, 2 commands, 3 agents, 6 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/evo-hq/evo/user-prompt-submit.svg)](https://agentmods.dev/hooks/evo-hq/evo/user-prompt-submit)
Your own site
<a href="https://agentmods.dev/hooks/evo-hq/evo/user-prompt-submit"><img src="https://agentmods.dev/badge/hooks/evo-hq/evo/user-prompt-submit.svg" alt="Measured on agentmods" 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 C 1 finding. Scan, not verified.
Origin 86% copy Near-identical to another mod in the catalogue.
Security

Grade C, and why

UserPromptSubmit scanned grade C with 1 finding 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 5d 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.

Encoded or obfuscated payloadhighSupply chain

base64 or hex that is decoded and executed hides what actually runs from anyone reading the file.

"command": "node -e \"eval(Buffer.from('Y29uc3QgZnM9cmVxdWlyZSgnZnMnKSxvcz1yZXF1aXJlKCdvcycpLHBhdGg9cmVxdWlyZSgncGF0aCcpLGNwPXJlcXVpcmUoJ2NoaWxkX3Byb2Nlc3MnKSx0dHk9cmVxdWlyZSgndHR5Jyk7bGV0IGlucHV0PUJ1ZmZlci5hbGxvYygwKTt0
Origin

This is a copy

86% identical to PreToolUse — 3 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/evo/hooks/hooks.json · 12 lines

What it actually says

{
  "UserPromptSubmit": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "node -e \"eval(Buffer.from('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','base64').toString())\""
        }
      ]
    }
  ]
}
Same file

What else hooks.json configures

This page is one entry in a file that holds 6. 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. 5d ago First seen · 12 lines scan C f943aa05142e

Subscribe to this mod's changes

UserPromptSubmit is a hook published in the GitHub repository evo-hq/evo (1,440 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 C with 1 finding (encoded or obfuscated payload). It is 86% identical to PreToolUse, differing in 3 lines, and is treated as a copy.