MCP Server — References

The specification a server implements, the error and pagination conventions worth copying, and the description formats a surface is frequently generated from.

What is being implemented

• Model Context Protocol — the specification and documentation for the server side: declaring capabilities during initialisation, advertising tools, resources, and prompts, and reporting results. Linked at the root because revision paths and section anchors have changed between releases.
• JSON-RPC 2.0 Specification — the message layer, and specifically the distinction between an error object and a successful response carrying an application-level failure, which is the distinction a server's error design rests on.

Designing the exposed surface

• OpenAPI Specification — operation, parameter, and response description; both the format most existing surfaces are generated from and a reminder of how different an endpoint listing is from a task surface.
• JSON Schema — the vocabulary for declaring arguments; the practical question for a server author is which keywords the calling model's runtime will actually enforce.

Error and failure reporting

• RFC 9457: Problem Details for HTTP APIs — a machine-readable problem type plus a human-readable explanation, the established shape for an error a caller can branch on without parsing prose.
• RFC 9110: HTTP Semantics: status-code semantics for the HTTP transport, including which classes a caller is entitled to retry.

No verified reference is recorded for tool-granularity guidance, for writing descriptions aimed at a model reader, or for versioning an advertised surface against connected clients. These remain conventions rather than published practice.