arc_apply_config · ARC Config MCP Server MCP: Risk & Policy

WHAT IT DOES

What arc_apply_config does on ARC Config MCP Server

AI agents invoke arc_apply_config 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_apply_config needs a policy

Applying configuration to a Kubernetes cluster triggers external operations that modify cluster state, including deploying or reconfiguring runners and controllers. This is an Execute-category action with high severity because misconfiguration or malicious input could disrupt CI/CD infrastructure, affect scaling behavior, or expose cluster resources.

From the tool's definition 'Apply ARC configuration from generated config files in your repository to the Kubernetes cluster'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

arc_apply_config Rate-limited

arc_apply_config 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_apply_config": {
      "limits": [
        {
          "counter": "arc_apply_config_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_apply_config

What does the arc_apply_config tool do? +

Apply ARC configuration from generated config files in your repository to the Kubernetes cluster. 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_apply_config? +

Register the ARC Config MCP Server MCP server in PolicyLayer and add a rule for arc_apply_config: 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_apply_config? +

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

Can I rate-limit arc_apply_config? +

Yes. Add a rate_limit block to the arc_apply_config 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_apply_config completely? +

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

arc_apply_config 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.