brain_install_hook
AI agents invoke brain_install_hook to trigger actions in Mcp Brain. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The name 'brain_install_hook' suggests installing some kind of hook — most likely a git hook or system-level hook — which would cause external code to execute on future events. This is an Execute-level action at minimum. However, the description is empty, which significantly lowers confidence.
From the tool's definition Tool name: 'brain_install_hook' — 'install_hook' strongly implies installing a hook (e.g., git hook, event hook, or lifecycle hook) which triggers code execution
Documented attack patterns abuse exactly the kind of access brain_install_hook gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Brain, and nothing reaches the server without passing your rules. This is the rule we recommend for brain_install_hook:
{
"version": "1",
"default": "deny",
"tools": {
"brain_install_hook": {
"limits": [
{
"counter": "brain_install_hook_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}brain_install_hook stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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brain_install_hook. It is categorised as a Execute tool in the Mcp Brain MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Mcp Brain MCP server in PolicyLayer and add a rule for brain_install_hook: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mcp Brain. Nothing to install.
brain_install_hook is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the brain_install_hook rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for brain_install_hook. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
brain_install_hook is provided by the Mcp Brain MCP server (pierfrancescolijoi/mcp-brain). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Brain, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
21 Mcp Brain tools catalogued and risk-classified — across an index of 43,000+ MCP servers.