PreToolUse

A pre-action check that runs before an agent writes to or edits a file, then records the changed file path in a local memory service.

In plain words
What is it for?
It is for tracking files modified by Write or Edit tool calls through an HTTP request to a local service.
Why use it?
It provides a record of file changes without requiring the agent to remember them manually.

Hook

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/iii-experimental/agentos/pre-tool-use
Clone the repo
git clone --depth 1 https://github.com/iii-experimental/agentos
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 B 2 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Security

Grade B, and why

PreToolUse scanned grade B with 2 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 3d 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

"command": "curl -s -X POST http://localhost:3111/api/memory/store -H 'Content-Type: application/json' -d '{\"agentId\":\"claude-code\",\"content\":\"File modified: $TOOL_INPUT_file_path\",\"role\":\"system\"}'",

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

"command": "curl -s -X POST http://localhost:3111/api/memory/store -H 'Content-Type: application/json' -d '{\"agentId\":\"claude-code\",\"content\":\"File modified: $TOOL_INPUT_file_path\",\"role\":\"system\"}'",
plugin/hooks/hooks.json · 16 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "^(Write|Edit)$",
      "description": "Track file changes for agent memory",
      "hooks": [
        {
          "type": "command",
          "command": "curl -s -X POST http://localhost:3111/api/memory/store -H 'Content-Type: application/json' -d '{\"agentId\":\"claude-code\",\"content\":\"File modified: $TOOL_INPUT_file_path\",\"role\":\"system\"}'",
          "timeout": 3000,
          "continueOnError": true
        }
      ]
    }
  ]
}
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. 3d ago First seen · 16 lines scan B 0c22e137b5be

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository iii-experimental/agentos (162 stars, last pushed 3mo 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 B with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.