Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add ArcticFox2029/chamnan/plugin install chamnanWrote 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.
[](https://agentmods.dev/hooks/arcticfox2029/chamnan/pre-tool-use)<a href="https://agentmods.dev/hooks/arcticfox2029/chamnan/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/arcticfox2029/chamnan/pre-tool-use.svg" alt="Measured on agentmods" height="20"></a>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.
What it actually says
{
"PreToolUse": [
{
"matcher": "Read",
"hooks": [
{
"type": "command",
"command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/bulk_read_notice.py\""
}
]
}
]
}What else hooks.json configures
This page is one entry in a file that holds 4. Installing the file brings all of them; each is measured and scanned on its own page.
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 3fd6d65f11c6
PreToolUse is a hook published in the GitHub repository ArcticFox2029/chamnan (4 stars, last pushed 5d 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.
Other hooks, from other repositories
PreToolUse
Runs before the agent uses a tool for run_command, view_file, grep_search, web_fetch and read_url_content tool calls, running context-mode hook antigravity-cli pretooluse. From mksglu/context-mode.
PostToolUse
Runs after a tool call finishes, running context-mode hook antigravity-cli posttooluse. From mksglu/context-mode.
Stop
Runs when the agent finishes a response, running context-mode hook antigravity-cli stop. From mksglu/context-mode.
SessionStart
Runs when a session starts, executing session_setup.py, session_init.py, smart_cleanup.py, session_inventory.py and update_check.py (5 commands). From sheeki03/Few-Word.
PreToolUse
Runs before the agent uses a tool for Bash and mcp__* tool calls, executing offload_bash.py and mcp_interceptor.py (2 commands). From sheeki03/Few-Word.
SessionEnd
Runs when a session ends, executing archive_plan.py. From sheeki03/Few-Word.