MCP's Skills Extension (SEP-2640) was merged and marked Final on September 13, after five months as a pull request
SEP-2640 defines the `skill://` resource convention for serving Agent Skills over MCP, with `skill://index.json` as the discovery document, `skill://<path>/SKILL.md` for the skill body, sibling files addressable as resources, and archive (ZIP/TAR) distribution as an alternative. It was opened by pja-ant on April 23, 2026, accumulated 54 commits, and was merged September 13 after a Core Maintainer vote, with conformance tests and reference implementations already in place across the Python, C#, Go and TypeScript SDKs. For builders this ends the copy-the-skill-folder-into-every-deployment pattern: an agent declares the `io.modelcontextprotocol/skills` capability at initialize and pulls skills on demand from a server, so server-side skill edits propagate without a reinstall.
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