k8s_apply · RedisNexus MCP: Risk & Policy

WHAT IT DOES

What k8s_apply does on RedisNexus

AI agents invoke k8s_apply 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_apply needs a policy

Applying YAML manifests to a Kubernetes cluster can create, modify, or replace any cluster resource (deployments, RBAC roles, secrets, etc.). This is an Execute-level action with critical blast radius because a malicious or erroneous manifest could compromise the entire cluster, escalate privileges, expose secrets, or disrupt production workloads.

From the tool's definition 'Apply a YAML manifest to the cluster' — this triggers Kubernetes resource creation or modification by deploying arbitrary YAML manifests to a live cluster.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

k8s_apply Rate-limited

k8s_apply 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_apply": {
      "limits": [
        {
          "counter": "k8s_apply_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_apply

What does the k8s_apply tool do? +

Apply a YAML manifest to the cluster. Supports dry_run mode for safe preview. 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_apply? +

Register the RedisNexus MCP server in PolicyLayer and add a rule for k8s_apply: 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_apply? +

k8s_apply is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit k8s_apply? +

Yes. Add a rate_limit block to the k8s_apply 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_apply completely? +

Set action: deny in the PolicyLayer policy for k8s_apply. 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_apply? +

k8s_apply 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.