mermaid_to_excalidraw · Arch7 MCP: Risk & Policy

WHAT IT DOES

What mermaid_to_excalidraw does on Arch7

AI agents use mermaid_to_excalidraw to create or update resources in Arch7 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Arch7 environment.

WHY IT NEEDS A POLICY

Why mermaid_to_excalidraw needs a policy

The tool converts Mermaid diagrams to Excalidraw format, which creates or transforms diagram data (a Write operation). It does not execute arbitrary code or delete data. The conversion process modifies/creates diagram structures but is reversible. Low severity because misuse would only result in unwanted diagram creation/format changes with no external side effects or data loss.

From the tool's definition Tool name 'mermaid_to_excalidraw' indicates conversion/transformation of Mermaid syntax into Excalidraw diagram format. Server description indicates tools for 'creating, modifying, and converting diagrams.' Description is empty, reducing confidence.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mermaid_to_excalidraw Rate-limited

mermaid_to_excalidraw 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": {
    "mermaid_to_excalidraw": {
      "limits": [
        {
          "counter": "mermaid_to_excalidraw_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 Arch7, so you can run agents against it safely.

FAQ

Questions about mermaid_to_excalidraw

What does the mermaid_to_excalidraw tool do? +

mermaid_to_excalidraw. It is categorised as a Write tool in the Arch7 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mermaid_to_excalidraw? +

Register the Arch7 MCP server in PolicyLayer and add a rule for mermaid_to_excalidraw: 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 Arch7. Nothing to install.

What risk level is mermaid_to_excalidraw? +

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

Can I rate-limit mermaid_to_excalidraw? +

Yes. Add a rate_limit block to the mermaid_to_excalidraw 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 mermaid_to_excalidraw completely? +

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

mermaid_to_excalidraw is provided by the Arch7 MCP server (ktcrisis/arch7). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.