PostToolUse

PostToolUse is a hook for Claude Code from danielmiessler/LifeOS. Its token cost is not measured, scanned A, original, MIT.

A post-tool hook that runs selected commands after agent, web, search, MCP, question and file or shell tools finish.

In plain words
What is it for?
Running safety checks on web and external-tool calls, recording agent activity and updating tab or work state after tools run.
Why use it?
It adds automatic checks and state updates around tool use, helping the agent track safety and session changes.

Hook for Claude Code

Written for Claude Code: PostToolUse hook event. Also seen: names the AskUserQuestion tool.

One of 11 entries in hooks.json upstream. Installing this one merges just its entry into your config; the other 10 are separate, each on its own page.

Good fit Running safety checks on web and external-tool calls, recording agent activity and updating tab or work state after tools run.

Compare 6 hooks from other repositories ↓
Install with agentmods
npx agentmods add hooks/danielmiessler/lifeos/post-tool-use
About the project

LifeOS is an AI-assisted personal operating system that records a person’s goals, values, context, and current situation to help move them toward a desired future state. It supports work such as building applications, starting businesses, and creative projects. Its catalogue entries extend the system through skills, hooks, agents, and commands.

danielmiessler/LifeOS · 19,494 stars · on GitHub · ourlifeos.ai

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/danielmiessler/LifeOS

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 PostToolUse

README.md
[![agentmods](https://agentmods.dev/badge/hooks/danielmiessler/lifeos/post-tool-use/github.svg)](https://agentmods.dev/hooks/danielmiessler/lifeos/post-tool-use)
Your own site
<a href="https://agentmods.dev/hooks/danielmiessler/lifeos/post-tool-use"><img src="https://agentmods.dev/badge/hooks/danielmiessler/lifeos/post-tool-use/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 PostToolUse

Your own site · 80×15
<a href="https://agentmods.dev/hooks/danielmiessler/lifeos/post-tool-use"><img src="https://agentmods.dev/badge/hooks/danielmiessler/lifeos/post-tool-use.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. ✓ AI security review Fable 5.1 · 7 Sept 2026 📄 Read the review
Origin original No closer match found in the catalogue.
Security

Grade A, and why

PostToolUse 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 1mo 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.

LifeOS/install/hooks/hooks.json · 213 lines

How it starts

The opening of the file, as written. The whole thing — 213 lines — stays where its author put it; the contents beside it link to each section on GitHub.

{
  "PostToolUse": [
    {
      "matcher": "Agent",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/AgentInvocation.hook.ts"
        }
      ]
    },
    {
      "matcher": "WebFetch",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/Safety.hook.ts",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "WebSearch",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/Safety.hook.ts",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "mcp__.*",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/Safety.hook.ts",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "ToolSearch",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/Safety.hook.ts",
          "timeout": 5
        }
      ]
    },
    {
      "matcher": "AskUserQuestion",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/TabState.hook.ts"
        }
      ]
    },
    {
      "matcher": "Read",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/ISAStaleWriteGuard.hook.ts"
        }
      ]
    },
    {
      "matcher": "Write",
      "hooks": [
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/ISASync.hook.ts"
        },
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/ISAStaleWriteGuard.hook.ts"
        },
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/CheckpointPerISC.hook.ts",
          "timeout": 30
        },
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/ConfigEvalFire.hook.ts"
        },
        {
          "type": "command",
          "command": "$HOME/.claude/hooks/AtlasEventCapture.hook

Read the full file on GitHub · 213 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. 1mo ago First seen · 213 lines scan A 5004a9c918b7

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository danielmiessler/LifeOS (19,494 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.