format_range · Excel MCP Server MCP: Risk & Policy

WHAT IT DOES

What format_range does on Excel MCP Server

AI agents use format_range 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 format_range needs a policy

This tool modifies Excel workbook state by changing cell formatting properties. It qualifies as Write rather than Read because it changes data (formatting attributes), but it is reversible and does not destroy data or execute arbitrary code. The low severity reflects that formatting changes have minimal blast radius—users can undo formatting mistakes without data loss.

From the tool's definition Tool description states 'Apply formatting to a range of cells.' Formatting operations modify cell appearance (styles, colors, fonts, alignment) but do not alter underlying data values or structure in a way that cannot be easily reversed.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

format_range Rate-limited

format_range 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": {
    "format_range": {
      "limits": [
        {
          "counter": "format_range_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 format_range

What does the format_range tool do? +

Apply formatting to a range of cells. 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 format_range? +

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

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

Can I rate-limit format_range? +

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

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

format_range is provided by the Excel MCP Server MCP server (thibaudvandendooren-acumen/excel-mcp-server-v2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.