snapshot_scene · Excalidraw MCP Server MCP: Risk & Policy

WHAT IT DOES

What snapshot_scene does on Excalidraw MCP Server

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

WHY IT NEEDS A POLICY

Why snapshot_scene needs a policy

This tool creates/saves a named snapshot of canvas state — a Write operation that persists data (the snapshot) for later use. It is reversible and does not delete or overwrite existing canvas content. Severity is medium because misuse could clutter snapshot storage or overwrite an important named snapshot, but it doesn't irreversibly destroy data.

From the tool's definition Save a named snapshot of the current canvas state for later restoration

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

snapshot_scene Rate-limited

snapshot_scene 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": {
    "snapshot_scene": {
      "limits": [
        {
          "counter": "snapshot_scene_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 Excalidraw MCP Server, so you can run agents against it safely.

FAQ

Questions about snapshot_scene

What does the snapshot_scene tool do? +

Save a named snapshot of the current canvas state for later restoration. It is categorised as a Write tool in the Excalidraw 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 snapshot_scene? +

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

What risk level is snapshot_scene? +

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

Can I rate-limit snapshot_scene? +

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

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

snapshot_scene is provided by the Excalidraw MCP Server MCP server (kakacoding1/mcp_excalidraw). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.