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.
npx agentmods add hooks/jkheadley/instar/pre-tool-usegit clone --depth 1 https://github.com/JKHeadley/instarWrote 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/jkheadley/instar/pre-tool-use)<a href="https://agentmods.dev/hooks/jkheadley/instar/pre-tool-use"><img src="https://agentmods.dev/badge/hooks/jkheadley/instar/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 4d 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": "AskUserQuestion",
"hooks": [
{
"type": "command",
"command": "bash $CLAUDE_PROJECT_DIR/.claude/hooks/free-text-guard.sh",
"blocking": true,
"timeout": 5000
}
]
},
{
"matcher": "mcp__.*",
"hooks": [
{
"type": "command",
"command": "node .instar/hooks/instar/external-operation-gate.js",
"blocking": true,
"timeout": 5000
}
]
},
{
"matcher": "Write|Edit|MultiEdit",
"hooks": [
{
"type": "command",
"command": "node $CLAUDE_PROJECT_DIR/.claude/hooks/duplicate-build-start-gate.js",
"blocking": true,
"timeout": 15000
}
]
}
]
}What else settings.json configures
This page is one entry in a file that holds 14. Installing the file brings all of them; each is measured and scanned on its own page.
- Settings file settings A not measured
- Hook PermissionRequest A not measured
- Hook PostToolUse A not measured
- Hook PreCompact A not measured
- Hook SessionEnd A not measured
- Hook SessionStart A not measured
- Hook Stop A not measured
- Hook SubagentStart A not measured
- Hook SubagentStop A not measured
- Hook TaskCompleted A not measured
- Hook UserPromptSubmit A not measured
- Hook WorktreeCreate A not measured
- Hook WorktreeRemove A not measured
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.
- 4d ago First seen · 37 lines scan A cf909e8cfd56
PreToolUse is a hook published in the GitHub repository JKHeadley/instar (77 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 2026-08-30.
Other hooks, from other repositories
PreToolUse
Runs before the agent uses a tool for Bash tool calls, executing code_scanner_hook.py, observability_hook.py and pii_checker_hook.py via python3 (3 commands). From alibaba/anolisa.
Stop
Runs when the agent finishes a response, running an inline shell check. From markmhendrickson/neotoma.
PreCompact
Runs before the context is compacted, executing on_pre_compact.sh. From atomicstrata/atomicmemory.
PreToolUse
Runs before the agent uses a tool for Write and Edit tool calls, executing block_memory_write.sh. From atomicstrata/atomicmemory.
PostCompact
Runs after the context is compacted, executing on_post_compact.sh. From atomicstrata/atomicmemory.
TaskCompleted
Runs when a task is marked completed, executing on_task_completed.sh. From atomicstrata/atomicmemory.