AI agents call mongodb_count to retrieve information from Db without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves statistical information about documents matching a query in MongoDB. It performs no writes, deletions, or side effects—purely a read operation that counts matching records. The low severity reflects that counting documents cannot cause data loss or unauthorized modifications, only information disclosure.
From the tool's definition Tool name 'mongodb_count' and description '统计 MongoDB 集合中匹配的文档数量' (count matching documents in MongoDB collection) indicate a query/retrieval operation that returns aggregate information without modifying data.
Documented attack patterns abuse exactly the kind of access mongodb_count gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Db, and nothing reaches the server without passing your rules. This is the rule we recommend for mongodb_count:
{
"version": "1",
"default": "deny",
"tools": {
"mongodb_count": {}
}
}mongodb_count is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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统计 MongoDB 集合中匹配的文档数量. It is categorised as a Read tool in the Db MCP Server, which means it retrieves data without modifying state.
Register the Db MCP server in PolicyLayer and add a rule for mongodb_count: 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 Db. Nothing to install.
mongodb_count 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 mongodb_count 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 mongodb_count. 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.
mongodb_count is provided by the Db MCP server (wannanbigpig/db-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Db, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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34 Db tools catalogued and risk-classified — across an index of 43,000+ MCP servers.