create_er_diagram · StarUML MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_er_diagram does on StarUML MCP Server

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

WHY IT NEEDS A POLICY

Why create_er_diagram needs a policy

Based on the naming pattern consistent with sibling tools (create_activity_diagram, create_class_diagram, etc.) and the server's purpose of generating UML diagrams, this tool likely creates an ER diagram in StarUML. 'Create' implies writing/generating new content. The description is empty, which lowers confidence, but the pattern strongly suggests a Write action.

From the tool's definition Tool name 'create_er_diagram' and server context: 'Enables AI to remotely control StarUML for generating UML diagrams (use case, class, sequence, ER, etc.)'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_er_diagram Rate-limited

create_er_diagram 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_er_diagram": {
      "limits": [
        {
          "counter": "create_er_diagram_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 StarUML MCP Server, so you can run agents against it safely.

FAQ

Questions about create_er_diagram

What does the create_er_diagram tool do? +

create_er_diagram. It is categorised as a Write tool in the StarUML 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_er_diagram? +

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

What risk level is create_er_diagram? +

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

Can I rate-limit create_er_diagram? +

Yes. Add a rate_limit block to the create_er_diagram 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_er_diagram completely? +

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

create_er_diagram is provided by the StarUML MCP Server MCP server (stonesho/staruml_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.