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SEP-2640: Skills Extension #1140
Description
Expected Behavior
The Java SDK should support the SEP-2640 Skills extension, enabling MCP clients to discover and retrieve Agent Skills exposed by MCP servers.
The SDK should provide:
- Schema types and method constants for
skills/list,skills/get, and the optionalresources/directory/read. - Client APIs to list skills, retrieve a skill entry by its
SKILL.mdURI, read skill resources, and—when advertised—read directory resources. - Stateless server APIs to register skills and expose the required endpoints.
- Support for
io.modelcontextprotocol/skillscapability negotiation, including the optionaldirectoryReadsetting.
Current Behavior
The SDK does not yet support the SEP-2640 Skills extension.
Context
This change adds support for the SEP-2640 Skills extension to the Java SDK, aligning it with the following implementations in other MCP SDKs:
- Python SDK: python-sdk#3485
- C# SDK: csharp-sdk#1856
- Go SDK: go-sdk#1238
I implemented this before realizing that non-trivial changes should be discussed with maintainers first. I would appreciate feedback on the proposed scope and API design, and I am happy to revise the implementation accordingly.
Reacted by Nicolás Míguez García, Edward Alexander Rojas and xfdzcoder
Activity
Ben-Home commentedon Sep 30, 2026
xfdzcoder commentedon Nov 13, 2026
Could #1214 land as the modern server portion of SEP-2640 once reviewed, with this issue staying open to track Java client support and a decision on the classic server scope in #1141?
In a local run against #1214 with a build-time Resources dependency check, all 45 Skills conformance checks passed over HTTP. The SDK docs describe using the conformance suite to exercise the server while the modern Java client is pending. Modern server docs