start_heartbeat · ZAP MCP Server MCP: Risk & Policy

WHAT IT DOES

What start_heartbeat does on ZAP MCP Server

AI agents invoke start_heartbeat to trigger actions in ZAP 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_heartbeat needs a policy

This tool executes a background operation (heartbeat process) whose effects are system-level and ongoing. While the operation itself is benign and necessary for server stability, it constitutes execution of a process.

From the tool's definition start_heartbeat initiates a heartbeat mechanism, which is an operational control that triggers a repeated background process to prevent server timeouts.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_heartbeat Rate-limited

start_heartbeat 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_heartbeat": {
      "limits": [
        {
          "counter": "start_heartbeat_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 ZAP MCP Server, so you can run agents against it safely.

FAQ

Questions about start_heartbeat

What does the start_heartbeat tool do? +

Start heartbeat mechanism to prevent MCP server timeouts. It is categorised as a Execute tool in the ZAP 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_heartbeat? +

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

What risk level is start_heartbeat? +

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

Can I rate-limit start_heartbeat? +

Yes. Add a rate_limit block to the start_heartbeat 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_heartbeat completely? +

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

start_heartbeat is provided by the ZAP MCP Server MCP server (lisberndt/zap-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.