AI agents use copy_sheet 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.
Copying a worksheet creates new data within the workbook (a Write action) but is fully reversible by deleting the copied sheet. It does not permanently destroy data (Destructive), execute arbitrary code (Execute), or move money (Financial). The medium severity reflects that careless copying could consume storage or create confusion, but the operation is non-destructive and can be undone.
From the tool's definition Tool description states 'Copy a worksheet within the workbook' — this creates a new duplicate sheet, which is a reversible data creation operation.
Documented attack patterns abuse exactly the kind of access copy_sheet gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Excel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for copy_sheet:
{
"version": "1",
"default": "deny",
"tools": {
"copy_sheet": {
"limits": [
{
"counter": "copy_sheet_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}copy_sheet 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.
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Copy a worksheet within the workbook. 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.
Register the Excel MCP Server MCP server in PolicyLayer and add a rule for copy_sheet: 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.
copy_sheet is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the copy_sheet 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.
Set action: deny in the PolicyLayer policy for copy_sheet. 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.
copy_sheet is provided by the Excel MCP Server MCP server (mort-lab/excel-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Excel MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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17 Excel MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.