k8s_nodes · RedisNexus MCP: Risk & Policy

WHAT IT DOES

What k8s_nodes does on RedisNexus

AI agents invoke k8s_nodes to trigger actions in RedisNexus. 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 k8s_nodes needs a policy

While listing nodes is a Read operation, the ability to cordon (mark unschedulable), uncordon, and drain nodes constitutes Execute-level operations with significant blast radius. Draining a node evicts all running pods, which can cause service disruption in production. These actions are irreversible in the sense that draining actively terminates workloads, though cordoning/uncordoning is reversible.

From the tool's definition Cordon/uncordon/drain nodes — these are operational actions that affect node scheduling and workload placement in a Kubernetes cluster, not merely reads.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

k8s_nodes Rate-limited

k8s_nodes 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": {
    "k8s_nodes": {
      "limits": [
        {
          "counter": "k8s_nodes_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 RedisNexus, so you can run agents against it safely.

FAQ

Questions about k8s_nodes

What does the k8s_nodes tool do? +

List cluster nodes with status, capacity, and resource usage. Cordon/uncordon/drain nodes. It is categorised as a Execute tool in the RedisNexus MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on k8s_nodes? +

Register the RedisNexus MCP server in PolicyLayer and add a rule for k8s_nodes: 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 RedisNexus. Nothing to install.

What risk level is k8s_nodes? +

k8s_nodes is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit k8s_nodes? +

Yes. Add a rate_limit block to the k8s_nodes 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 k8s_nodes completely? +

Set action: deny in the PolicyLayer policy for k8s_nodes. 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 k8s_nodes? +

k8s_nodes is provided by the RedisNexus MCP server (rajkumar-madhu/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.