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 avanturer/claude-bestpractice/plugin install claude-bestpracticeWrote 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/avanturer/claude-bestpractice/session-start)<a href="https://agentmods.dev/hooks/avanturer/claude-bestpractice/session-start"><img src="https://agentmods.dev/badge/hooks/avanturer/claude-bestpractice/session-start.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
SessionStart 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.
What it actually says
{
"SessionStart": [
{
"$comment": [
"`fork` is a source like any other, and leaving it out of this matcher is not a",
"conservative default — it is this gate not running at all on a forked session.",
"`--fork-session` resumes a session under a NEW id in the SAME worktree, so the",
"fork gets no board, no registration, no reap and no pre-push arming, which is",
"the entire coordination layer, on exactly the workflow this product is for.",
"",
"Enforcement is unaffected either way: `evidence-gate` adopts a missing record",
"at `branch_point`, never at HEAD, so an unregistered session is over-reported",
"rather than let through. What a fork loses is awareness, not the gate."
],
"matcher": "startup|resume|clear|compact|fork",
"hooks": [
{
"type": "command",
"command": "${CLAUDE_PLUGIN_ROOT}/bin/session-start",
"timeout": 30,
"statusMessage": "claude-bestpractice: session board"
}
]
}
]
}What else hooks.json configures
This page is one entry in a file that holds 10. 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 Changed · +11 lines 288cfa8a6fd2
- 3d ago First seen · 15 lines scan A c037fe0c0fa1
SessionStart is a hook published in the GitHub repository avanturer/claude-bestpractice (1 stars, last pushed today), 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
SessionStart
Runs when a session starts on startup, resume, clear and compact, executing session-start.cjs and hook-skill-suggest.cjs via node (2 commands). From PralhadYadawad/avvarre.
PreToolUse
Runs before the agent uses a tool for ^apply_patch$, ^write_to_file$, ^replace_file_content$ and ^multi_replace_file_content$ tool calls, executing impact-warn.cjs via node. From PralhadYadawad/avvarre.
Stop
Runs when the agent finishes a response, executing session-end.cjs via node. From PralhadYadawad/avvarre.
SessionStart
Runs when a session starts on startup and resume, executing deja.sh. From vshulcz/deja-vu.
PreToolUse
Runs before the agent uses a tool for Edit, Write, Grep, Glob, Bash, Edit, Write, NotebookEdit and Bash tool calls, executing spec-hint.js, module-hint.js and docs-hint.js via node (3 commands). From kaanozhan/Frame.
PreToolUse
Runs before the agent uses a tool for Edit and Write tool calls, running an inline shell check. From zernie/vigiles.