AI agents invoke compare_documents to trigger actions in Docx. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool name suggests comparing two documents. In the context of a Word document MCP server that supports track changes, document comparison typically generates a new document or inserts tracked changes (a write/execute operation). However, the description is empty, so confidence is low.
From the tool's definition Tool name: compare_documents; description is empty and uninformative.
Documented attack patterns abuse exactly the kind of access compare_documents gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Docx, and nothing reaches the server without passing your rules. This is the rule we recommend for compare_documents:
{
"version": "1",
"default": "deny",
"tools": {
"compare_documents": {
"limits": [
{
"counter": "compare_documents_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}compare_documents stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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compare_documents. It is categorised as a Execute tool in the Docx MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Docx MCP server in PolicyLayer and add a rule for compare_documents: 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 Docx. Nothing to install.
compare_documents is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the compare_documents 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 compare_documents. 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.
compare_documents is provided by the Docx MCP server (securityronin/docx-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Docx, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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219 Docx tools catalogued and risk-classified — across an index of 43,000+ MCP servers.