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/helweg/open-codebase-index/session-startgit clone --depth 1 https://github.com/Helweg/open-codebase-indexGrade 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 2d 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 '\nFor repository questions, use index_status when readiness is unknown, then call codebase_context before shell search, grep, or broad file reads. Pass symbol for definitions or from+to for dependency paths; use specialized lookup and graph tools afterward.\\n'",
"commandWindows": "Write-Output 'For repository questions, use index_status when readiness is unknown, then call codebase_context before shell search, grep, or broad file reads. Pass symbol for definitions or from+to for dependency paths; use specialized lookup and graph tools afterward.'",
"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.
- 2d ago First seen · 15 lines scan A 703044247dab
SessionStart is a hook published in the GitHub repository Helweg/open-codebase-index (183 stars, last pushed 2d 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
SessionStart
Runs when a session starts, executing ensure-deps.js, sync.js and session-context.js via node (3 commands). From sagarmk/beacon-plugin.
PostToolUse
Runs after a tool call finishes for Write, Edit, MultiEdit and Bash tool calls, executing embed-file.js and gc.js via node (2 commands). From sagarmk/beacon-plugin.
PreToolUse
Runs before the agent uses a tool for Grep and Bash tool calls, executing grep-intercept.js via node. From sagarmk/beacon-plugin.
PreCompact
Runs before the context is compacted, executing status.js via node with --compact-warning. From sagarmk/beacon-plugin.
SessionStart
Runs when a session starts, running an inline shell check. From roomi-fields/rtfm.
PostToolUse
Runs after a tool call finishes for Write, Edit, MultiEdit and NotebookEdit tool calls, running an inline shell check. From roomi-fields/rtfm.