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/kouroshez/coding-os/subagent-startgit clone --depth 1 https://github.com/kouroshez/coding-osWrote 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/kouroshez/coding-os/subagent-start)<a href="https://agentmods.dev/hooks/kouroshez/coding-os/subagent-start"><img src="https://agentmods.dev/badge/hooks/kouroshez/coding-os/subagent-start.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
SubagentStart 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 today.
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.
This is a copy
75% identical to PreToolUse — 276 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
{
"SubagentStart": [
{
"matcher": "",
"hooks": [
{
"type": "command",
"command": "env COS_AGENT=claude \".claude/hooks/agent-presence.sh\"",
"timeout": 5
}
]
}
]
}What else settings.json configures
This page is one entry in a file that holds 9. 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.
- today First seen · 14 lines scan A bc0be13dfca8
SubagentStart is a hook published in the GitHub repository kouroshez/coding-os (6 stars, last pushed 3d 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 A with 0 findings. It is 75% identical to PreToolUse, differing in 276 lines, and is treated as a copy.
Other hooks, from other repositories
SessionStart
Runs when a session starts, executing session-start.sh. From HKUDS/LightRAG.
SessionStart
Runs when a session starts, executing world-model-session.js via node. From SaravananJaichandar/world-model-mcp.
PreToolUse
Runs before the agent uses a tool for Bash, Edit, Write, MultiEdit and NotebookEdit tool calls, executing block-npm-publish.sh, block-unsafe-git.sh and block-generated-edit.sh (3 commands). From wlsdks/ontology-atlas.
SessionStart
Runs when a session starts, executing skeptic-suggest.sh via bash. From gambletan/cortex.
Stop
Runs when the agent finishes a response, executing contextdb-memory-hook.py via python3. From mikhailbovt/ContextDB-Codex.
SessionStart
Runs when a session starts, running agent-recall-session-start. From mnardit/agent-recall.