SessionStart

SessionStart is a hook for Claude Code from skynetcmd/m3-memory. Its token cost is not measured, scanned A, original, Apache-2.0.

A session-start hook that checks whether the mcp-memory command-line tool is available. If it is missing, it prints an installation suggestion.

In plain words
What is it for?
Use it at the beginning of agent sessions that depend on mcp-memory. It checks the command path automatically and points to a pipx installation command when needed.
Why use it?
It warns early when a required memory tool is not installed, instead of letting the problem appear later during a task.

Hook for Claude Code

Written for Claude Code: SessionStart hook event. Also seen: mentions Codex.

Part of the m3 plugin — 16 skills, 15 commands, 2 agents, 3 hooks, 2 MCP servers shipped together

One of 3 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 2 are separate, each on its own page.

Good fit Use it at the beginning of agent sessions that depend on mcp-memory. It checks the command path automatically and points to a pipx installation command when needed.

Compare 6 hooks from other repositories ↓
Install with agentmods
npx agentmods add hooks/skynetcmd/m3-memory/session-start
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.

Clone the repo
git clone --depth 1 https://github.com/skynetcmd/m3-memory

Made for: Claude Code.

Or install m3, the plugin that ships this one along with the rest of its 16 skills, 15 commands, 2 agents, 3 hooks, 2 MCP servers.

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/skynetcmd/m3-memory/session-start/github.svg)](https://agentmods.dev/hooks/skynetcmd/m3-memory/session-start)
Your own site
<a href="https://agentmods.dev/hooks/skynetcmd/m3-memory/session-start"><img src="https://agentmods.dev/badge/hooks/skynetcmd/m3-memory/session-start/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 SessionStart

Your own site · 80×15
<a href="https://agentmods.dev/hooks/skynetcmd/m3-memory/session-start"><img src="https://agentmods.dev/badge/hooks/skynetcmd/m3-memory/session-start.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

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.

plugins/codex/hooks/hooks.json · 15 lines

What it actually says

{
  "SessionStart": [
    {
      "matcher": "startup|resume",
      "hooks": [
        {
          "type": "command",
          "command": "command -v m3 >/dev/null 2>&1 || { echo '[m3-memory] m3 CLI not on PATH. Run: pipx install m3-memory && pipx ensurepath, then m3 setup' >&2; exit 1; }; exec m3 hook codex-session-start",
          "commandWindows": "where m3 >nul 2>nul || (echo [m3-memory] m3 CLI not on PATH. Run: pipx install m3-memory, then pipx ensurepath, then m3 setup 1>&2 & exit 1) & m3 hook codex-session-start",
          "timeout": 30
        }
      ]
    }
  ]
}
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.

  1. 4d ago Changed · +1 lines 68482373e3d4
  2. 1mo ago First seen · 14 lines scan A ceb02864993c

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository skynetcmd/m3-memory (29 stars, last pushed 5d 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.