A pre-action check that runs before the agent uses Bash, the command-line tool, and can reject unsafe or unsuitable command patterns.

Use it to check Bash commands for timeout usage before they run, especially when working locally on macOS or connecting to Linux machines.

It prevents a macOS-specific timeout command from failing silently and helps ensure remote commands use a working alternative.

PreToolUse — Hook by fcakyon

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/fcakyon/claude-codex-settings/pre-tool-use

Clone the repo

git clone --depth 1 https://github.com/fcakyon/claude-codex-settings

Made for: Claude Code.

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

PreToolUse 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 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.

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.

.claude/settings.json · 13 lines

What it actually says

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "bash -c 'CMD=$(jq -r \".tool_input.command\"); S=$(printf \"%s\" \"$CMD\" | sed -e \"s/'\\''[^'\\'']*'\\''//g\" -e \"s/\\\"[^\\\"]*\\\"//g\"); if printf \"%s\" \"$S\" | grep -qE \"(^|[;&|(){}]|[[:space:]]do|[[:space:]]then|[[:space:]]else)[[:space:]]*timeout[[:space:]]\"; then printf \"{\\\"hookSpecificOutput\\\":{\\\"hookEventName\\\":\\\"PreToolUse\\\",\\\"permissionDecision\\\":\\\"deny\\\",\\\"permissionDecisionReason\\\":\\\"macOS has no timeout command on this host, so timeout N ... exits 127 with empty output and silently hides the real result (a remote ssh sweep can look idle when it is not). Use ssh -o ConnectTimeout=N, or gtimeout N (brew coreutils), or for a remote Linux host put timeout inside the ssh quotes.\\\"}}\"; fi'"
        }
      ]
    }
  ]
}

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.

3d ago First seen · 13 lines scan A 07068adfac0f

Subscribe to this mod's changes

PreToolUse is a hook published in the GitHub repository fcakyon/claude-codex-settings (1,117 stars, last pushed yesterday), 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 A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

claude-code commit-message cursor gemini-cli github pull-requests

PreToolUse

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other hooks, from other repositories

PostToolUse

UserPromptSubmit

PreToolUse

Setup

Stop

SessionEnd