agentmods.dev

PostToolUse

A set of automatic actions that run after an AI agent edits files or fetches web content. These actions execute Node.js scripts to scan the change or fetched material.

In plain words
What is it for?
Use it to scan files after Edit or Write calls and scan content after WebFetch calls.
Why use it?
It helps apply checks immediately after tool calls, so problems can be detected without relying on someone to remember a separate check.

Hook

Part of the agent-guards plugin — 1 skill, 2 hooks shipped together

0 2d ago A scan tokens not measured original MIT
View the source file mlawsonking/MCP
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/mlawsonking/mcp/post-tool-use
Clone the repo
git clone --depth 1 https://github.com/mlawsonking/MCP

Or install agent-guards, the plugin that ships this one along with the rest of its 1 skill, 2 hooks.

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

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 2d 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.

agent-guards-plugin/hooks/hooks.json · 32 lines

What it actually says

{
  "PostToolUse": [
    {
      "matcher": "Edit|Write",
      "hooks": [
        {
          "type": "command",
          "command": "node",
          "args": [
            "${CLAUDE_PLUGIN_ROOT}/hooks/post-edit.mjs"
          ],
          "timeout": 10,
          "statusMessage": "scanning the change"
        }
      ]
    },
    {
      "matcher": "WebFetch",
      "hooks": [
        {
          "type": "command",
          "command": "node",
          "args": [
            "${CLAUDE_PLUGIN_ROOT}/hooks/post-fetch.mjs"
          ],
          "timeout": 10,
          "statusMessage": "scanning fetched content"
        }
      ]
    }
  ]
}
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. 2d ago First seen · 32 lines scan A 8136183acc1d

Subscribe to this mod's changes

PostToolUse is a hook published in the GitHub repository mlawsonking/MCP (0 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

agent-securityagent-security-toolsai-agentsapimcpmcp-server
Related

Other hooks, from other repositories

PostToolUse

Runs after a tool call finishes for EnterWorktree tool calls, running an inline shell check. From rejifald/StitchAPI.

rejifald/StitchAPI · not measured

PostToolUse

Runs after a tool call finishes for Edit and Write tool calls, running an inline shell check. From fo0/clawstash.

fo0/clawstash · not measured

SessionStart

Runs when a session starts, running echo 'Session start -- read MEMORY.md and SCRATCHPAD.md to r. From fo0/clawstash.

fo0/clawstash · not measured

PreToolUse

Runs before the agent uses a tool for Bash tool calls, running an inline shell check. From fo0/clawstash.

fo0/clawstash · not measured

SessionStart

Runs when a session starts, executing check-trustabl.sh. From trustabl/trustabl.

trustabl/trustabl · not measured

PreToolUse

Runs before the agent uses a tool for mcp__ayrshare__create_post, mcp__ayrshare__update_post, mcp__ayrshare__retry_post, mcp__ayrshare__add_comment, mcp__ayrshare__reply_comment, mcp__ayrshare__send_message, mcp__ayrshare__set_auto_response and mcp__ayrshare__create_profile tool calls, running an inline shell check.…

ayrshare/ayrshare-social-media-api-claude-plugin · not measured