update_diagram · RapidChart MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_diagram does on RapidChart MCP Server

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

WHY IT NEEDS A POLICY

Why update_diagram needs a policy

The tool creates or modifies diagram data reversibly. Users can update diagrams and the changes are not permanent deletions or destructive operations—they can be further modified or reverted. This fits the Write category (creates or modifies data reversibly).

From the tool's definition Tool name is 'update_diagram' and description states it will 'Update an existing diagram with new code' and 'regenerate the diagram'. This modifies existing diagram resources.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_diagram Rate-limited

update_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": {
    "update_diagram": {
      "limits": [
        {
          "counter": "update_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 RapidChart MCP Server, so you can run agents against it safely.

FAQ

Questions about update_diagram

What does the update_diagram tool do? +

Update an existing diagram with new code. The AI will regenerate the diagram with awareness of the old structure. It is categorised as a Write tool in the RapidChart 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 update_diagram? +

Register the RapidChart MCP Server MCP server in PolicyLayer and add a rule for update_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 RapidChart MCP Server. Nothing to install.

What risk level is update_diagram? +

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

Can I rate-limit update_diagram? +

Yes. Add a rate_limit block to the update_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 update_diagram completely? +

Set action: deny in the PolicyLayer policy for update_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 update_diagram? +

update_diagram is provided by the RapidChart MCP Server MCP server (samicostox/rapidchart-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.