List columns with headers from the first row of a sheet
AI agents call list_columns to retrieve information from Excel MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves schema/header information from an Excel sheet without side effects. It is a read-only query operation that extracts column metadata, fitting squarely into the Read category with minimal risk.
From the tool's definition Tool name 'list_columns' and description 'List columns with headers from the first row of a sheet' indicate data retrieval only. No modification, deletion, or execution is performed.
Attacks that exploit this kind of access
List columns with headers from the first row of a sheet. It is categorised as a Read tool in the Excel MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Excel MCP Server MCP server in PolicyLayer and add a rule for list_columns: 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.
list_columns is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_columns 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 list_columns. 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.
list_columns 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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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