start_timer · Rhizm MCP Server MCP: Risk & Policy

WHAT IT DOES

What start_timer does on Rhizm MCP Server

AI agents invoke start_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 start_timer needs a policy

The tool executes an operation with side effects: it initiates a timer and terminates any existing timer. While not destructive (timers can be stopped/reset) or financial, it is an active operation that modifies the state of the time-tracking system. Misuse could lead to incorrect time tracking or confusion about task duration.

From the tool's definition Tool description states 'Start a timer for the specified task. Stops any currently running timer first.' This performs an action (starting a timer, stopping a running timer) that triggers external state changes in the Rhizm system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_timer Rate-limited

start_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": {
    "start_timer": {
      "limits": [
        {
          "counter": "start_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 start_timer

What does the start_timer tool do? +

Start a timer for the specified task. Stops any currently running timer first. 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 start_timer? +

Register the Rhizm MCP Server MCP server in PolicyLayer and add a rule for start_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 start_timer? +

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

Can I rate-limit start_timer? +

Yes. Add a rate_limit block to the start_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 start_timer completely? +

Set action: deny in the PolicyLayer policy for start_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 start_timer? +

start_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.