MCP resources: exposing data to clients

MCP resources are data a server exposes for reading. Each resource has a URI; a client lists available resources with resources/list and reads one by its URI. Content comes back with a MIME type. Resources model data, whereas tools model actions.

A resource is identified by a URI. The URI is how a client addresses a specific piece of data — a document, a schema, a status object. The server defines which URIs it exposes.

A client discovers available resources through resources/list and can use resource templates to anticipate URIs. To retrieve content, it reads the resource by URI and receives the value plus its MIME type.

Resources are passive data the client reads. Tools are actions the client triggers. A version-control server might expose branches and files as resources and expose commit or merge operations as tools. Choosing one or the other affects how the client presents the server.