control_thread · Scouter MCP: Risk & Policy

WHAT IT DOES

What control_thread does on Scouter

AI agents invoke control_thread to trigger actions in Scouter. 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 control_thread needs a policy

This tool directly manipulates JVM threads (resume, suspend, stop, interrupt) on a running application agent. These are active execution-control operations with significant blast radius — stopping or interrupting threads in a production JVM can cause application crashes, deadlocks, or data corruption. The WARNING tag in the description further indicates high risk.

From the tool's definition Control a specific thread on a JVM agent: resume, suspend, stop, or interrupt

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

control_thread Rate-limited

control_thread 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": {
    "control_thread": {
      "limits": [
        {
          "counter": "control_thread_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 Scouter, so you can run agents against it safely.

FAQ

Questions about control_thread

What does the control_thread tool do? +

[HTTP mode only] Control a specific thread on a JVM agent: resume, suspend, stop, or interrupt. Use list_active_services to find active thread IDs, or get_agent_info to see all threads. WARNING:. It is categorised as a Execute tool in the Scouter MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on control_thread? +

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

What risk level is control_thread? +

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

Can I rate-limit control_thread? +

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

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

control_thread is provided by the Scouter MCP server (scouter-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.