add_worksheet · Excel MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_worksheet does on Excel MCP Server

AI agents use add_worksheet 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 add_worksheet needs a policy

Adding a worksheet creates new data structure within an Excel workbook but is reversible (worksheets can be deleted). This is a Write category action—it modifies the workbook by creating new content, but does not irreversibly destroy data, execute arbitrary code, or move money. Severity is medium because the blast radius is limited to workbook structure modification; the impact is constrained and reversible.

From the tool's definition Tool description states 'adds a worksheet to an existing workbook' (既存のワークブックにワークシートを追加します). This is a create/modify operation that creates new structure within a workbook.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_worksheet Rate-limited

add_worksheet 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": {
    "add_worksheet": {
      "limits": [
        {
          "counter": "add_worksheet_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 add_worksheet

What does the add_worksheet tool do? +

既存のワークブックにワークシートを追加します. 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 add_worksheet? +

Register the Excel MCP Server MCP server in PolicyLayer and add a rule for add_worksheet: 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 add_worksheet? +

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

Can I rate-limit add_worksheet? +

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

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

add_worksheet is provided by the Excel MCP Server MCP server (superpyonchix/excel_mcp_server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.