SessionStart

A startup and resume hook that prints key project instructions when a coding-agent session begins or resumes. It is configured for the c3-oss/codexcw repository.

In plain words
What is it for?
It reminds agents where each language implementation lives, which tools and commands to use, where examples are stored, and how commits are checked.
Why use it?
It puts the repository’s main rules and useful commands in front of the agent at the start of work, reducing missed setup details.

Hook for Claude Code

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/c3-oss/codexcw/session-start
Clone the repo
git clone --depth 1 https://github.com/c3-oss/codexcw

Made for: Claude Code.

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 yesterday.

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.

.claude/settings.json · 24 lines

What it actually says

{
  "SessionStart": [
    {
      "matcher": "startup",
      "hooks": [
        {
          "type": "command",
          "command": "printf '\\n=== c3-oss/codexcw ===\\n- Canonical guide: AGENTS.md (read it before substantial changes).\\n- Polyglot monorepo: Go at the root; Rust core in crates/codexcw; npm + PyPI in bindings/{node,python}.\\n- Toolchain: devbox + just (recipes are language-namespaced: go-*, rust-*, node-*, py-*).\\n- Usage examples: docs/examples/{go,rust,typescript,python}.md.\\n- Conventional Commits with required scope are enforced by commitlint.\\n- Local CI lane: `just ci`.\\n===\\n\\n'",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "resume",
      "hooks": [
        {
          "type": "command",
          "command": "printf '\\n=== c3-oss/codexcw ===\\n- Canonical guide: AGENTS.md (read it before substantial changes).\\n- Polyglot monorepo: Go at the root; Rust core in crates/codexcw; npm + PyPI in bindings/{node,python}.\\n- Toolchain: devbox + just (recipes are language-namespaced: go-*, rust-*, node-*, py-*).\\n- Usage examples: docs/examples/{go,rust,typescript,python}.md.\\n- Conventional Commits with required scope are enforced by commitlint.\\n- Local CI lane: `just ci`.\\n===\\n\\n'",
          "timeout": 5
        }
      ]
    }
  ]
}
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. yesterday First seen · 24 lines scan A 7c16b6c3abdb

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository c3-oss/codexcw (1 stars, last pushed yesterday), licensed CC0-1.0. 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 2026-08-31.