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.
git clone --depth 1 https://github.com/Helweg/open-codebase-indexWrote 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/helweg/open-codebase-index/session-start)<a href="https://agentmods.dev/hooks/helweg/open-codebase-index/session-start"><img src="https://agentmods.dev/badge/hooks/helweg/open-codebase-index/session-start/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/hooks/helweg/open-codebase-index/session-start"><img src="https://agentmods.dev/badge/hooks/helweg/open-codebase-index/session-start.svg" alt="Reviewed on agentmods" width="80" 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 12d 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
{
"SessionStart": [
{
"matcher": "startup|resume|clear|compact",
"hooks": [
{
"type": "command",
"command": "printf '\\nCheck index_status when readiness is unknown. Use one compact codebase_context first pass (tokenBudget: 600, limit: 5) only for unfamiliar repository orientation. Use implementation_lookup directly for known definitions and call_graph or call_graph_path directly for relationships. Read known paths and grep exact identifiers; use codebase_edit_context optionally for a known edit target. Do not repeat retrieval when existing evidence already answers the task.\\n'",
"commandWindows": "Write-Output 'Check index_status when readiness is unknown. Use one compact codebase_context first pass (tokenBudget: 600, limit: 5) only for unfamiliar repository orientation. Use implementation_lookup directly for known definitions and call_graph or call_graph_path directly for relationships. Read known paths and grep exact identifiers; use codebase_edit_context optionally for a known edit target. Do not repeat retrieval when existing evidence already answers the task.'",
"statusMessage": "Codebase Index ready"
}
]
}
]
}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.
- 12d ago Changed 349dc7c14cee
- 1mo ago First seen · 15 lines scan A 703044247dab
SessionStart is a hook published in the GitHub repository Helweg/open-codebase-index (224 stars, last pushed yesterday), 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 Grep and Bash tool calls, running an inline shell check. From denfry/codebase-index.
SessionStart
Runs when a session starts on startup, resume, clear and compact, running vectr hook session-start. From swapnanil/vectr.
SubagentStart
Runs when a subagent starts, running npx -y --package=@fatelabs/estelle@latest -- estelle hook co. From uqeu/estelle-cli.
SessionStart
Runs when a session starts, executing jarvis-index-status.sh. From jarvis-intelligence/jarvis-index.
PreToolUse
Runs before the agent uses a tool for Bash tool calls, running an inline shell check. From apache/superset.
PreToolUse
Runs before the agent uses a tool, executing pre-write.sh and pre-bash.sh (2 commands). From anthropics/claude-cookbooks.