MongoDB Lens is a local MCP server that exposes full-featured access to MongoDB databases via natural language, enabling LLMs to perform queries, run aggregations, optimize performance, and more. It ships with an extensive MCP toolset covering common database tasks (creating connections, querying, inserting, updating, deleting, aggregating, indexing, and more), along with resources and prompts to guide interactions. The server supports multiple MongoDB URIs with aliases in a config file, and can be run via NPX, Docker Hub, or from source. Configuration is flexible: a JSON/JSONC config file (with nested settings for connection options, caching, memory, and security), environment variable overrides, and a config:create script to generate config files. MongoDB Lens creates a per-database metadata collection recording origin, lens version, and startup context. It includes a token-based confirmation workflow for destructive operations, with an option to bypass in controlled environments. The project emphasizes data protection, data-flow considerations, and compatibility with MCP clients like Claude Desktop and MCP Inspector.