watch · Trace MCP: Risk & Policy

WHAT IT DOES

What watch does on Trace MCP

AI agents invoke watch to trigger actions in Trace MCP. 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 watch needs a policy

This tool triggers and manages a background process (file watcher) that continuously monitors files and automatically executes contract revalidation on changes. 'Start' initiates an ongoing external operation, 'stop' terminates it, and 'poll' retrieves pending events.

From the tool's definition Watch project files for changes and auto-revalidate contracts. Actions: start (begin watching), stop (end watching), status (check state), poll (get pending events).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

watch Rate-limited

watch 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": {
    "watch": {
      "limits": [
        {
          "counter": "watch_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 Trace MCP, so you can run agents against it safely.

FAQ

Questions about watch

What does the watch tool do? +

Watch project files for changes and auto-revalidate contracts. Actions: start (begin watching), stop (end watching), status (check state), poll (get pending events). It is categorised as a Execute tool in the Trace MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on watch? +

Register the Trace MCP server in PolicyLayer and add a rule for watch: 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 Trace MCP. Nothing to install.

What risk level is watch? +

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

Can I rate-limit watch? +

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

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

watch is provided by the Trace MCP server (mnehmos/mnehmos.trace.mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.