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/dev-jahn/hippocampus/session-startgit clone --depth 1 https://github.com/Dev-Jahn/hippocampusGrade 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 yesterday.
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 SessionStart — 4 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
{
"SessionStart": [
{
"matcher": "startup|resume|clear|compact",
"hooks": [
{
"type": "command",
"command": "bash \"${CLAUDE_PLUGIN_ROOT}/hooks/session_start.sh\"",
"timeout": 10
}
]
}
]
}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.
- yesterday First seen · 14 lines scan A cef0f45f039c
SessionStart is a hook published in the GitHub repository Dev-Jahn/hippocampus (4 stars, last pushed 19d 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. It is 75% identical to SessionStart, differing in 4 lines, and is treated as a copy.
Other hooks, from other repositories
Setup
Runs once when the project is set up, executing hooks.py via python3. From shanraisshan/claude-code-best-practice.
SessionStart
Runs when a session starts, executing llm_wiki_session.py via python3 with --harness and --if-enabled. From nvk/llm-wiki.
SessionStart
Runs when a session starts on startup, executing session_check.py via python3. From s0912758806p/agentic-sop-to-work.
SessionStart
Runs when a session starts, executing cli.js via node. From code-yeongyu/codex-rules.
PreToolUse
Runs before the agent uses a tool for Bash, Write and Write tool calls, running an inline shell check (3 commands). From Justdvp/claude-code-templates.
PreToolUse
Runs before the agent uses a tool for Write, Edit, Bash, Agent, Task, SendMessage and TaskStop tool calls, running bash (3 commands). From modu-ai/moai-adk.