MCP provides authentication options that ensure only authorized clients and tools can interact within the protocol. Though MCP keeps its core transport simple, it is designed to run over secure channels such as TLS or containerized environments where authentication happens at the connection boundary. In typical deployments, authentication is enforced by the MCP server rather than by individual tools. This means the server decides which clients may connect, what tools they can access, and what permissions each tool has. The protocol supports session metadata and capability negotiation, allowing servers to restrict access based on user identity or environment rules.
Developers can implement authentication using API keys, tokens, OAuth flows, or platform-specific authentication such as local OS permissions. Because MCP communication occurs over structured JSON messages, embedding authentication metadata into initialization messages is straightforward. Servers can require clients to present credentials during the connection handshake, and the server responds with the allowed tool set. This prevents unauthorized access to sensitive environments, such as MCP tools that read local files, modify datasets, or interact with proprietary Milvus collections.
For vector databases, authentication is especially important because embeddings and search results can contain sensitive information. MCP lets developers define which tools expose vector operations and who is allowed to call them. For example, an MCP server might allow only certain clients to write to a Milvus collection while allowing others to read but not modify. This separation ensures that vector pipelines remain secure, especially in multi-user environments where inadvertent writes or unauthorized queries could cause data leaks. MCP’s flexible authentication boundary helps developers enforce robust access control for retrieval workflows.