MCP resource

Definition

An MCP resource is read-only data an MCP server exposes for the model to reference — like a file, a record, or a document — addressed by a URI.

Resources are the 'nouns' to tools' 'verbs': data the model can read rather than actions it can take. In practice tools dominate and resources are used less often, but the distinction matters for safety — a resource is inherently lower-risk than a tool that executes something.