create-user · Keycloak MCP: Risk & Policy

WHAT IT DOES

What create-user does on Keycloak

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

WHY IT NEEDS A POLICY

Why create-user needs a policy

This tool creates a new user account, which is a reversible write operation. While it modifies system state by adding an identity to the authentication system, the action can be undone by deleting the user (as evidenced by the sibling 'delete-user' tool). It does not execute arbitrary code, delete data irreversibly, or move money, so it falls under Write rather than Execute, Destructive, or Financial.

From the tool's definition Tool name 'create-user' combined with description 'Create a new user in a specific realm' indicates creation of new data in Keycloak.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create-user Rate-limited

create-user 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-user": {
      "limits": [
        {
          "counter": "create-user_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 Keycloak, so you can run agents against it safely.

FAQ

Questions about create-user

What does the create-user tool do? +

Create a new user in a specific realm. It is categorised as a Write tool in the Keycloak 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-user? +

Register the Keycloak MCP server in PolicyLayer and add a rule for create-user: 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 Keycloak. Nothing to install.

What risk level is create-user? +

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

Can I rate-limit create-user? +

Yes. Add a rate_limit block to the create-user 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-user completely? +

Set action: deny in the PolicyLayer policy for create-user. 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-user? +

create-user is provided by the Keycloak MCP server (keycloak-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.