stop_timer · Rhizm MCP Server MCP: Risk & Policy

WHAT IT DOES

What stop_timer does on Rhizm MCP Server

AI agents invoke stop_timer to trigger actions in Rhizm MCP Server. 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 stop_timer needs a policy

This tool executes a command to stop a running timer—an operation that has side effects (state change in the Rhizm system) but is fully reversible (the timer can be restarted). It does not read-only retrieve data (Read), create/modify data reversibly in a persistent sense (Write), irreversibly destroy data (Destructive), or involve financial transactions (Financial).

From the tool's definition Tool name 'stop_timer' with description 'Stop the running timer for the specified task' indicates an action that triggers an external operation (halting a timer) whose effects depend on the task argument provided.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stop_timer Rate-limited

stop_timer 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": {
    "stop_timer": {
      "limits": [
        {
          "counter": "stop_timer_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 Rhizm MCP Server, so you can run agents against it safely.

FAQ

Questions about stop_timer

What does the stop_timer tool do? +

Stop the running timer for the specified task. It is categorised as a Execute tool in the Rhizm MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on stop_timer? +

Register the Rhizm MCP Server MCP server in PolicyLayer and add a rule for stop_timer: 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 Rhizm MCP Server. Nothing to install.

What risk level is stop_timer? +

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

Can I rate-limit stop_timer? +

Yes. Add a rate_limit block to the stop_timer 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 stop_timer completely? +

Set action: deny in the PolicyLayer policy for stop_timer. 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 stop_timer? +

stop_timer is provided by the Rhizm MCP Server MCP server (rhizmapp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.