agentmods.dev

SessionStart

A startup hook that runs a Node.js script when a session starts, is cleared, or is compacted.

In plain words
What is it for?
Use it to run session-start.mjs during startup, after clearing a session, or after its context is compacted.
Why use it?
It performs the same setup step automatically at important points in a coding-agent session.

Hook

1.4k 2d ago A scan tokens not measured copy · 61% MIT
View the source file hyhmrright/brooks-lint
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/hyhmrright/brooks-lint/session-start
Clone the repo
git clone --depth 1 https://github.com/hyhmrright/brooks-lint
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 61% copy Near-identical to another mod 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.

Origin

This is a copy

61% identical to SessionStart — 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.

hooks/hooks.json · 14 lines

What it actually says

{
  "SessionStart": [
    {
      "matcher": "startup|clear|compact",
      "hooks": [
        {
          "type": "command",
          "command": "node \"${CLAUDE_PLUGIN_ROOT}/hooks/session-start.mjs\"",
          "async": false
        }
      ]
    }
  ]
}
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 · 14 lines scan A ca47a577572c

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository hyhmrright/brooks-lint (1,432 stars, last pushed 2d 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. It is 61% identical to SessionStart, differing in 3 lines, and is treated as a copy.

Code reviewPlanningarchitecture-reviewclaude-code-pluginclean-architecturecode-qualitytech-debt
Related

Other hooks, from other repositories

PreCompact

Runs before the context is compacted for manual and auto tool calls, executing pre-compact.mjs. From jjanczur/tyran.

jjanczur/tyran · not measured

Stop

Runs when the agent finishes a response, executing preflight_audit.sh via bash. From sgaabdu4/building-flutter-apps.

sgaabdu4/building-flutter-apps · not measured

FileChanged

Runs on the FileChanged event for CLAUDE.md, .cursorrules, .windsurfrules and copilot-instructions.md tool calls, running arai guardrails --match-stdin. From taniwhaai/arai.

taniwhaai/arai · not measured

PreToolUse

Runs before the agent uses a tool for Write and Edit tool calls, executing protect-files-hook.js via node. From codenamev/ai-software-architect.

codenamev/ai-software-architect · not measured

InstructionsLoaded

Runs after instructions files are loaded, executing instructions-loaded-check.sh. From BaseInfinity/claude-sdlc-harness.

BaseInfinity/claude-sdlc-harness · not measured

PreToolUse

Runs before the agent uses a tool for Bash, Read, Write, Edit, Glob, Grep, mcp__.*, Bash, Task, Write and Edit tool calls, executing dispatch.cjs, pre-dispatch-conflict-check.cjs, mcp-call-gate.cjs, commit-attribution.cjs, task-track-model.cjs, security-critical-warn.cjs and phase-checkpoint.cjs via node (8 commands).…

nguyenthienthanh/aura-frog · not measured