AI agents call list_contexts to retrieve information from Cert Manager without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves kubeconfig context information, which is metadata about available Kubernetes cluster connections. Listing contexts is a read-only operation with no side effects, no code execution, and no data modification. The blast radius of misuse is minimal—an attacker gains visibility into cluster names/contexts but cannot modify or execute against them.
From the tool's definition Tool name 'list_contexts' and description 'List all kubeconfig contexts' indicate a retrieval operation with no side effects. It queries configuration data without modifying, executing, or deleting anything.
Documented attack patterns abuse exactly the kind of access list_contexts gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Cert Manager, and nothing reaches the server without passing your rules. This is the rule we recommend for list_contexts:
{
"version": "1",
"default": "deny",
"tools": {
"list_contexts": {}
}
}list_contexts is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
List all kubeconfig contexts. It is categorised as a Read tool in the Cert Manager MCP Server, which means it retrieves data without modifying state.
Register the Cert Manager MCP server in PolicyLayer and add a rule for list_contexts: 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 Cert Manager. Nothing to install.
list_contexts is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_contexts 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.
Set action: deny in the PolicyLayer policy for list_contexts. 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.
list_contexts is provided by the Cert Manager MCP server (pibblokto/cert-manager-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Cert Manager, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
8 Cert Manager tools catalogued and risk-classified — across an index of 43,000+ MCP servers.