render_diagram · Vizdown- MCP: Risk & Policy

WHAT IT DOES

What render_diagram does on Vizdown-MCP

AI agents invoke render_diagram to trigger actions in Vizdown-MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why render_diagram needs a policy

Rendering a diagram involves executing a rendering engine (Mermaid.js or custom SVG renderer) and potentially writing output files to disk. This goes beyond a simple read operation. The description is empty, so confidence is reduced, but based on sibling tools and server context, this tool likely triggers an execution pipeline to produce output files.

From the tool's definition Tool name is 'render_diagram'; server description states it 'renders' diagrams using Mermaid.js and custom SVG renderers, and can export in SVG, PNG, and PDF formats.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

render_diagram Rate-limited

render_diagram stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "render_diagram": {
      "limits": [
        {
          "counter": "render_diagram_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about render_diagram

What does the render_diagram tool do? +

render_diagram. It is categorised as a Execute tool in the Vizdown-MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on render_diagram? +

Register the Vizdown- MCP server in PolicyLayer and add a rule for render_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 Vizdown-MCP. Nothing to install.

What risk level is render_diagram? +

render_diagram is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit render_diagram? +

Yes. Add a rate_limit block to the render_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 render_diagram completely? +

Set action: deny in the PolicyLayer policy for render_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 render_diagram? +

render_diagram is provided by the Vizdown- MCP server (rutika196/clarity-beta). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.