SessionStart

SessionStart is a hook for Claude Code from kouroshez/coding-os. Its token cost is not measured, scanned A, original, Apache-2.0.

Runs when a session starts on startup, resume, startup, resume, compact and resume, executing check-mcp-extras.sh, session-skill-primer.sh, rules-primer.sh, remind-daily.sh, ensure-hub-up.sh, session-context.sh, agent-presence.sh, warn-mcp-down.sh, auto-brain-decay.sh, reclaim-sweep.sh, warn-graph-empty.sh…

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/kouroshez/coding-os/session-start
Clone the repo
git clone --depth 1 https://github.com/kouroshez/coding-os

Made for: Claude Code.

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/kouroshez/coding-os/session-start.svg)](https://agentmods.dev/hooks/kouroshez/coding-os/session-start)
Your own site
<a href="https://agentmods.dev/hooks/kouroshez/coding-os/session-start"><img src="https://agentmods.dev/badge/hooks/kouroshez/coding-os/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 unknown 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 today.

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.

tests/golden/claude_base/.claude/settings.json · 160 lines

How it starts

The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "SessionStart": [
    {
      "matcher": "startup",
      "hooks": [
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/check-mcp-extras.sh\"",
          "statusMessage": "🔌 Checking MCP extras health...",
          "timeout": 30
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/session-skill-primer.sh\"",
          "statusMessage": "🧠 Priming required-skill card...",
          "timeout": 10
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/rules-primer.sh\"",
          "statusMessage": "📋 Priming workflow-integrity rules card...",
          "timeout": 10
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/remind-daily.sh\"",
          "statusMessage": "🗓️  Checking daily check-in recency...",
          "timeout": 10
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/ensure-hub-up.sh\"",
          "statusMessage": "🛰️  Ensuring Coding OS Hub is up...",
          "timeout": 30
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/session-context.sh\"",
          "statusMessage": "🚀 Loading session context + memory digest...",
          "timeout": 30
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/agent-presence.sh\"",
          "timeout": 5
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/warn-mcp-down.sh\"",
          "statusMessage": "🩺 Probing MCP coding-os liveness...",
          "timeout": 30
        },
        {
          "type": "command",
          "command": "env COS_AGENT=claude \".claude/hooks/auto-brain-decay.sh\"",
          "statusMessage": "📉 Debounced pattern-decay sweep...",
          "timeo

Read the full file on GitHub · 160 lines

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. today First seen · 160 lines scan A ca1e3c44db5a

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository kouroshez/coding-os (6 stars, last pushed 3d 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 2026-09-03.