AI agents call list_databases 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 retrieves metadata about available databases without creating, modifying, or deleting any data. It is a simple enumeration operation with minimal blast radius. The server explicitly advertises read-only access, and listing databases is a non-destructive query operation.
From the tool's definition Tool name 'list_databases' and server description states 'read-only access to MongoDB databases'. The tool lists databases with no modification capability.
Documented attack patterns abuse exactly the kind of access list_databases gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MongoDB MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_databases:
{
"version": "1",
"default": "deny",
"tools": {
"list_databases": {}
}
}list_databases is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
List all databases in the MongoDB server. 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 list_databases: 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.
list_databases 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_databases 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_databases. 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_databases is provided by the MongoDB MCP Server MCP server (jonfreeland/mongodb-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MongoDB MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
5 MongoDB MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.