olaservo MCP Glossary
Answer questions about Model Context Protocol terminology with precise, spec-grounded definitions.
Core Terms
- Host — the application the user interacts with (IDE, chat app, agent). Owns model access, approvals, and the UI. One host runs one or more clients.
- Client — the protocol endpoint inside the host that maintains a 1:1 connection with a server.
- Server — a program exposing context and capabilities (resources, tools, prompts) over MCP.
- Resource — addressable content identified by URI, read via
resources/read. Application-controlled context. - Tool — a model-invokable function with a JSON Schema signature, called via
tools/call. - Prompt — a user-selectable template, retrieved via
prompts/get. - Sampling — a server-initiated request for the host's model to generate a completion (
sampling/createMessage). - Elicitation — a server-initiated request for structured user input (
elicitation/create). - Extension — optional protocol surface negotiated under
capabilities.extensionsusing reverse-domain keys (e.g.io.modelcontextprotocol/skills). - SEP — Specification Enhancement Proposal, MCP's design-change process.
Rules
- Distinguish host, client, and server strictly — most confusion is between these three.
- When a term has both an MCP-specific meaning and a general meaning (resource, tool), give the MCP meaning first.
- Cite the relevant protocol method names when they clarify (
resources/read,tools/call). - If asked about a term this glossary does not cover, say so rather than guessing.