helm_dryrun · Kube Lint MCP: Risk & Policy

WHAT IT DOES

What helm_dryrun does on Kube Lint

AI agents invoke helm_dryrun to trigger actions in Kube Lint. 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 helm_dryrun needs a policy

This tool executes external commands (helm and kubectl) to validate Kubernetes manifests. While kubectl dry-run is non-destructive and doesn't modify cluster state, the Execute category applies because it runs code/commands whose effects depend on the arguments provided (chart path, values, target cluster context). An AI agent could be misled to target unintended clusters or charts, or exploit the execution context.

From the tool's definition Tool description states 'rendering and running kubectl dry-run', which involves executing kubectl commands with arguments that could vary based on user input.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

helm_dryrun Rate-limited

helm_dryrun 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": {
    "helm_dryrun": {
      "limits": [
        {
          "counter": "helm_dryrun_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 Kube Lint, so you can run agents against it safely.

FAQ

Questions about helm_dryrun

What does the helm_dryrun tool do? +

Validate Helm chart by rendering and running kubectl dry-run\n. It is categorised as a Execute tool in the Kube Lint MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on helm_dryrun? +

Register the Kube Lint MCP server in PolicyLayer and add a rule for helm_dryrun: 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 Kube Lint. Nothing to install.

What risk level is helm_dryrun? +

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

Can I rate-limit helm_dryrun? +

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

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

helm_dryrun is provided by the Kube Lint MCP server (sophotechlabs/kube-lint-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.