end_session · MCP Session Closer MCP: Risk & Policy

WHAT IT DOES

What end_session does on MCP Session Closer

AI agents invoke end_session to trigger actions in MCP Session Closer. 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.

WHY IT NEEDS A POLICY

Why end_session needs a policy

This tool performs multiple external operations: syncing context files across systems, updating Agent OS files, and automatically committing changes to git with descriptive messages. These are chained side-effect operations that trigger external systems. While individual steps might be Write-level, the automatic git commit and multi-system orchestration makes this Execute-level.

From the tool's definition 'commit to git', 'sync all context files', 'update Agent OS files', 'ending a work session'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

end_session Rate-limited

end_session 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "end_session": {
      "limits": [
        {
          "counter": "end_session_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP Session Closer, so you can run agents against it safely.

FAQ

Questions about end_session

What does the end_session tool do? +

Close the current Cursor session, sync all context files, update Agent OS files, and commit to git. This is the main tool for ending a work session. It is categorised as a Execute tool in the MCP Session Closer MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on end_session? +

Register the MCP Session Closer MCP server in PolicyLayer and add a rule for end_session: 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 Session Closer. Nothing to install.

What risk level is end_session? +

end_session is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit end_session? +

Yes. Add a rate_limit block to the end_session 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.

How do I block end_session completely? +

Set action: deny in the PolicyLayer policy for end_session. 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.

What MCP server provides end_session? +

end_session is provided by the MCP Session Closer MCP server (tylarcam/mcp-session-closer). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.