create_postgres_role · CloudNativePG MCP Server MCP

WHAT IT DOES

What create_postgres_role does on CloudNativePG MCP Server

AI agents use create_postgres_role to create or update resources in CloudNativePG MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your CloudNativePG MCP Server environment.

WHY IT NEEDS A POLICY

Why create_postgres_role needs a policy

This tool creates database users/roles, which is a reversible modification to the database state. While role creation itself doesn't directly delete or execute arbitrary code, it materially alters the database security posture and access control configuration. The auto-generated password handling and role creation justify Write category.

From the tool's definition Tool creates a new PostgreSQL role/user, which modifies the PostgreSQL security model and state. Description explicitly states 'Create a new PostgreSQL role (user)' indicating a reversible creation operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_postgres_role Rate-limited

create_postgres_role stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_postgres_role": {
      "limits": [
        {
          "counter": "create_postgres_role_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches CloudNativePG MCP Server, so you can run agents against it safely.

FAQ

Questions about create_postgres_role

What does the create_postgres_role tool do? +

Create a new PostgreSQL role (user) with auto-generated password. It is categorised as a Write tool in the CloudNativePG MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_postgres_role? +

Register the CloudNativePG MCP Server MCP server in PolicyLayer and add a rule for create_postgres_role: 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 CloudNativePG MCP Server. Nothing to install.

What risk level is create_postgres_role? +

create_postgres_role is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_postgres_role? +

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

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

create_postgres_role is provided by the CloudNativePG MCP Server MCP server (wateim/cnpg-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.