export_diagram · Diagram MCP: Risk & Policy

WHAT IT DOES

What export_diagram does on DiagramMCP

AI agents use export_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 export_diagram needs a policy

The export_diagram tool creates output files in various formats (SVG, PNG, etc.) from diagram definitions. This is a Write operation as it generates new data artifacts, albeit reversibly.

From the tool's definition Tool name 'export_diagram' and description 'Export diagram to various formats (returns instructions for rendering)' indicate diagram file creation/modification operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

export_diagram Rate-limited

export_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": {
    "export_diagram": {
      "limits": [
        {
          "counter": "export_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 export_diagram

What does the export_diagram tool do? +

Export diagram to various formats (returns instructions for rendering). 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 export_diagram? +

Register the Diagram MCP server in PolicyLayer and add a rule for export_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 export_diagram? +

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

Can I rate-limit export_diagram? +

Yes. Add a rate_limit block to the export_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 export_diagram completely? +

Set action: deny in the PolicyLayer policy for export_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 export_diagram? +

export_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.