create_class_diagram · Diagram MCP: Risk & Policy

WHAT IT DOES

What create_class_diagram does on DiagramMCP

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

WHY IT NEEDS A POLICY

Why create_class_diagram needs a policy

The tool creates diagram artifacts (reversible data generation). The empty description lowers confidence somewhat, but the naming pattern and server context clearly indicate this generates a UML class diagram as structured data. This is a Write operation—it produces new content without side effects beyond the diagram itself, and the output can be discarded or regenerated without harm.

From the tool's definition Tool name is 'create_class_diagram'; server description states it 'Enables the dynamic generation of various software development diagrams' and lists similar creation tools (create_architecture_diagram, create_flowchart, etc.)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_class_diagram Rate-limited

create_class_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_class_diagram": {
      "limits": [
        {
          "counter": "create_class_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 DiagramMCP, so you can run agents against it safely.

FAQ

Questions about create_class_diagram

What does the create_class_diagram tool do? +

create_class_diagram. It is categorised as a Write tool in the DiagramMCP 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_class_diagram? +

Register the Diagram MCP server in PolicyLayer and add a rule for create_class_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 DiagramMCP. Nothing to install.

What risk level is create_class_diagram? +

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

Can I rate-limit create_class_diagram? +

Yes. Add a rate_limit block to the create_class_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_class_diagram completely? +

Set action: deny in the PolicyLayer policy for create_class_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_class_diagram? +

create_class_diagram is provided by the Diagram MCP server (lelondelonmelon/diagrammcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.