create_workbook · Excel MCP: Risk & Policy

WHAT IT DOES

What create_workbook does on Excel

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

WHY IT NEEDS A POLICY

Why create_workbook needs a policy

This tool creates a new workbook, which is a reversible Write operation. It does not execute code, delete data, or commit financial transactions. The blast radius is minimal—a new empty workbook can be easily deleted. Severity is low because accidental or malicious creation of workbooks causes no data loss or system compromise.

From the tool's definition Tool name 'create_workbook' and description 'Create a new Excel workbook' indicate creation of a new file/data structure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_workbook Rate-limited

create_workbook 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_workbook": {
      "limits": [
        {
          "counter": "create_workbook_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, so you can run agents against it safely.

FAQ

Questions about create_workbook

What does the create_workbook tool do? +

Create a new Excel workbook. It is categorised as a Write tool in the Excel 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_workbook? +

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

What risk level is create_workbook? +

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

Can I rate-limit create_workbook? +

Yes. Add a rate_limit block to the create_workbook 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_workbook completely? +

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

create_workbook is provided by the Excel MCP server (shmaxi/excel-mcp-server-node). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.