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SessionStart

SessionStart is a hook for coding agents from marcelopaniza/mempenny. Its token cost is not measured, scanned A, original, MIT.

A session-start hook that runs a script called nap-check.sh when a coding session begins. It can check which supported host is starting the session.

In plain words
What is it for?
Use it to run startup checks for Claude, Codex, or Gemini sessions when the required script is available.
Why use it?
It automates a check at the beginning of each session, so you do not have to remember to run it yourself.

Hook

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 mempenny plugin — 2 skills, 18 commands, 1 agent, 1 hook shipped together

not rated 2 14d ago A scan tokens not measured original MIT
View the source file marcelopaniza/mempenny
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 marcelopaniza/mempenny
Claude Code
/plugin install mempenny

Or install mempenny, the plugin that ships this one along with the rest of its 2 skills, 18 commands, 1 agent, 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 SessionStart

README.md
[![agentmods](https://agentmods.dev/badge/hooks/marcelopaniza/mempenny/session-start.svg)](https://agentmods.dev/hooks/marcelopaniza/mempenny/session-start)
Your own site
<a href="https://agentmods.dev/hooks/marcelopaniza/mempenny/session-start"><img src="https://agentmods.dev/badge/hooks/marcelopaniza/mempenny/session-start.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 A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Security

Grade A, and why

SessionStart 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 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.

hooks/hooks.json · 21 lines

What it actually says

{
  "SessionStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "if [ -n \"${CLAUDE_PLUGIN_ROOT:-}\" ] && [ -x \"${CLAUDE_PLUGIN_ROOT}/hooks/nap-check.sh\" ]; then \"${CLAUDE_PLUGIN_ROOT}/hooks/nap-check.sh\"; fi"
        },
        {
          "type": "command",
          "command": "if [ -n \"${PLUGIN_ROOT:-}\" ] && [ -x \"${PLUGIN_ROOT}/hooks/nap-check.sh\" ]; then MEMPENNY_HOST=codex \"${PLUGIN_ROOT}/hooks/nap-check.sh\"; fi"
        },
        {
          "type": "command",
          "command": "if [ -n \"${GEMINI_SESSION_ID:-}\" ] && [ -x \"${extensionPath}/hooks/nap-check.sh\" ]; then MEMPENNY_HOST=gemini \"${extensionPath}/hooks/nap-check.sh\"; fi",
          "timeout": 10000
        }
      ]
    }
  ]
}
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 · 21 lines scan A 35337a8d8657

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository marcelopaniza/mempenny (2 stars, last pushed 14d 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 2026-08-31.

LLMclaude-codeclaude-plugintokenstriage
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