mcp-server

Paths below are relative to this skill's directory.

Scope

Designing and implementing an MCP server, and reviewing or releasing one: which primitive a capability belongs to, how tools are named and schema'd, what a result may cost the caller, what an error says, which transport to speak and how not to corrupt it, how authorization works when the server is an OAuth resource server, which threats exist because the thing is an MCP server, and how to verify all of it.

Version-sensitive throughout. The current specification revision is 2026-07-28, and the shipping SDKs do not all implement it. Every rule below that depends on the revision carries a gate, and references/sdk-versions.md holds the measured matrix plus the commands to re-measure it. Treat a claim about "the MCP version" as ambiguous until someone says whether they mean the specification revision or an SDK release.

Not covered: authoring agent skills. Writing a SKILL.md, its frontmatter, references or evaluations is the skill-authoring skill's job, including the draft extension that distributes skills over MCP.