end_session

THE RISK

Low Risk

Why end_session needs a policy

With no description available, the tool's behavior can only be guessed from its name. 'end_session' suggests terminating a session or connection, which is most likely an administrative/cleanup action rather than reading, writing, executing, destroying data, or moving money. Confidence is low due to the empty description.

From the tool's definition Tool name is 'end_session' and description is empty or uninformative.

Documented attack patterns abuse exactly the kind of access end_session gives an agent:

POLICY

How to control end_session

PolicyLayer is an MCP gateway — it sits between your AI agents and Zulip, and nothing reaches the server without passing your rules. This is the rule we recommend for end_session:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "end_session": {
      "limits": [
        {
          "counter": "end_session_rate",
          "window": "minute",
          "max": 60,
          "scope": "grant"
        }
      ]
    }
  }
}

end_session gets a rate cap, and everything else on the server is denied unless you say otherwise.

Create a free account and register Zulip — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

SET A RULE FOR THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Tool risk categories → How PolicyLayer classifies MCP tools by what they can do.
MCP tool → What an MCP tool is and how clients discover and call it.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about end_session

What does the end_session tool do? +

end_session. It is categorised as a Other tool in the Zulip MCP Server, which means it performs auxiliary operations.

How do I enforce a policy on end_session? +

Register the Zulip 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 Zulip. Nothing to install.

What risk level is end_session? +

end_session is a Other tool with low risk. Read-only tools are generally safe to allow by default.

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 Zulip MCP server (windborne/zulipmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Zulip tool call.

Start from Zulip, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →