AI agents use set_cell_value to create or update resources in Libreoffice — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Libreoffice environment.
This tool modifies spreadsheet cell values, creating or overwriting data reversibly. While the empty description reduces confidence slightly, the tool name and server context (LibreOffice Calc operations) clearly indicate a Write operation. Severity is high because spreadsheet data modification could affect downstream analyses, reports, or business logic that depend on that data.
From the tool's definition Tool name 'set_cell_value' with empty description. Sibling tools include 'calculate_statistics', 'create_chart', 'create_table', etc., indicating a LibreOffice Calc spreadsheet manipulation context.
Documented attack patterns abuse exactly the kind of access set_cell_value gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Libreoffice, and nothing reaches the server without passing your rules. This is the rule we recommend for set_cell_value:
{
"version": "1",
"default": "deny",
"tools": {
"set_cell_value": {
"limits": [
{
"counter": "set_cell_value_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_cell_value 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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set_cell_value. It is categorised as a Write tool in the Libreoffice MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Libreoffice MCP server in PolicyLayer and add a rule for set_cell_value: 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 Libreoffice. Nothing to install.
set_cell_value 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 set_cell_value 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 set_cell_value. 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.
set_cell_value is provided by the Libreoffice MCP server (waterpistolai/libreoffice-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Libreoffice, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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24 Libreoffice tools catalogued and risk-classified — across an index of 43,000+ MCP servers.