agentmods.dev

SessionStart

A session-start hook that runs setup commands when a coding-agent session begins and cleanup commands when the session is compacted. Compaction shortens old conversation context so work can continue.

In plain words
What is it for?
Use it to run discover.mjs at session start and compact-cleanup.mjs when a compact event occurs.
Why use it?
It automates discovery and cleanup at two points where manual session maintenance can otherwise be missed.

Hook

7 1mo ago A scan tokens not measured copy · 55% MIT
View the source file zhebil/claude-code-plugins
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/zhebil/claude-code-plugins/session-start
Clone the repo
git clone --depth 1 https://github.com/zhebil/claude-code-plugins
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 55% 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

55% identical to SessionStart — 16 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.

plugins/auto-enrich/hooks/hooks.json · 23 lines

What it actually says

{
  "SessionStart": [
    {
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/discover.mjs",
          "timeout": 30
        }
      ]
    },
    {
      "matcher": "compact",
      "hooks": [
        {
          "type": "command",
          "command": "node ${CLAUDE_PLUGIN_ROOT}/hooks/compact-cleanup.mjs",
          "timeout": 10
        }
      ]
    }
  ]
}
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 · 23 lines scan A 694c3c09c4c7

Subscribe to this mod's changes

SessionStart is a hook published in the GitHub repository zhebil/claude-code-plugins (7 stars, last pushed 1mo 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 55% identical to SessionStart, differing in 16 lines, and is treated as a copy.

Productivityclaude-codeclaude-code-marketplaceclaude-code-plugingithubhooksjira
Related

Other hooks, from other repositories

PreToolUse

Runs before the agent uses a tool for Edit, Write, NotebookEdit, Read, Skill, Agent and Task tool calls, executing hook-launcher.mjs and pre-agent-inject.sh via node (3 commands). From sdsrss/claude-mem-lite.

sdsrss/claude-mem-lite · not measured

PostToolUse

Runs after a tool call finishes for Write, Edit, Write, Edit, Write and Edit tool calls, executing check-file-size.sh, lint-on-edit.sh and check-silent-errors.sh (3 commands). From sneg55/agent-starter.

sneg55/agent-starter · not measured

SessionStart

Runs when a session starts, executing emit_style_context.py via python3. From liatrio-labs/claude-code-gauntlet.

liatrio-labs/claude-code-gauntlet · not measured

SessionStart

Runs when a session starts, executing cli.js via node. From code-yeongyu/codex-rules.

code-yeongyu/codex-rules · not measured

UserPromptSubmit

Runs when you submit a prompt, before the agent sees it, executing user-prompt.mjs via node. From oliverjueguen/workingon-claude-skill.

oliverjueguen/workingon-claude-skill · not measured

SessionEnd

Runs when a session ends, executing session-end.mjs via node. From oliverjueguen/workingon-claude-skill.

oliverjueguen/workingon-claude-skill · not measured