arc_scale_runners · ARC Config MCP Server MCP: Risk & Policy

WHAT IT DOES

What arc_scale_runners does on ARC Config MCP Server

AI agents invoke arc_scale_runners to trigger actions in ARC Config 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 arc_scale_runners needs a policy

Scaling runners in a Kubernetes cluster is an Execute action—it triggers infrastructure changes whose effects depend on the scaling arguments provided (number of runners, resource allocation, etc.).

From the tool's definition Tool performs 'Scale GitHub Actions runners' which executes infrastructure scaling operations in Kubernetes clusters.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

arc_scale_runners Rate-limited

arc_scale_runners 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": {
    "arc_scale_runners": {
      "limits": [
        {
          "counter": "arc_scale_runners_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 ARC Config MCP Server, so you can run agents against it safely.

FAQ

Questions about arc_scale_runners

What does the arc_scale_runners tool do? +

Scale GitHub Actions runners with intelligent cost and performance recommendations. It is categorised as a Execute tool in the ARC Config 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 arc_scale_runners? +

Register the ARC Config MCP Server MCP server in PolicyLayer and add a rule for arc_scale_runners: 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 ARC Config MCP Server. Nothing to install.

What risk level is arc_scale_runners? +

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

Can I rate-limit arc_scale_runners? +

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

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

arc_scale_runners is provided by the ARC Config MCP Server MCP server (tsviz/arc-config-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.