create_chart · Excel MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_chart does on Excel MCP Server

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

WHY IT NEEDS A POLICY

Why create_chart needs a policy

This tool creates new chart objects within an Excel workbook, which is a reversible write operation. Charts can be deleted (as evidenced by the delete_chart sibling tool), so the modification is not permanent.

From the tool's definition Tool description: "Create a chart from data in a sheet". The name "create_chart" and description explicitly indicate data creation/addition to the workbook without deletion or irreversible modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_chart Rate-limited

create_chart 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": {
    "create_chart": {
      "limits": [
        {
          "counter": "create_chart_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 Excel MCP Server, so you can run agents against it safely.

FAQ

Questions about create_chart

What does the create_chart tool do? +

Create a chart from data in a sheet. It is categorised as a Write tool in the Excel 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 create_chart? +

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

What risk level is create_chart? +

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

Can I rate-limit create_chart? +

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

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

create_chart is provided by the Excel MCP Server MCP server (jauinones/xlsx-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.