Find a single document matching a query
AI agents call findOne to retrieve information from MongoDB MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns a single document from a MongoDB collection. It is a read-only operation with no side effects: it does not create, modify, delete, or execute code.
From the tool's definition Tool name is 'findOne' with description 'Find a single document matching a query' — retrieves data without modifying or deleting it.
Attacks that exploit this kind of access
Find a single document matching a query. It is categorised as a Read tool in the MongoDB MCP Server MCP Server, which means it retrieves data without modifying state.
Register the MongoDB MCP Server MCP server in PolicyLayer and add a rule for findOne: 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 MongoDB MCP Server. Nothing to install.
findOne 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 findOne 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 findOne. 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.
findOne is provided by the MongoDB MCP Server MCP server (ryaker/mongodb-mcp-server). 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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