tm_stop_run · Tm MCP: Risk & Policy

WHAT IT DOES

What tm_stop_run does on Tm

AI agents invoke tm_stop_run to trigger actions in Tm. 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 tm_stop_run needs a policy

While stopping a run is reversible (a new run can be started), it executes a command that affects the state of an external system (TrafficMorph's test infrastructure). This fits Execute rather than Write because it triggers an operational action on a service rather than creating/modifying persistent data. The idempotency note confirms it's a state-change operation.

From the tool's definition "Stop the in-flight run for a profile" — this terminates an active load-testing operation, which is an external operation with real-world effects (halting ongoing test execution).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

tm_stop_run Rate-limited

tm_stop_run 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": {
    "tm_stop_run": {
      "limits": [
        {
          "counter": "tm_stop_run_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 Tm, so you can run agents against it safely.

FAQ

Questions about tm_stop_run

What does the tm_stop_run tool do? +

Stop the in-flight run for a profile. Fully idempotent —. It is categorised as a Execute tool in the Tm MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on tm_stop_run? +

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

What risk level is tm_stop_run? +

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

Can I rate-limit tm_stop_run? +

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

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

tm_stop_run is provided by the Tm MCP server (trafficmorph-gif/tm-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.