Add SkillCatalog and FilesystemSkillProvider for serving skills from a provider

Author: vijaydeepsinha

src/mcp/server/skills/__init__.py

@@ -0,0 +1,32 @@
+"""The Skills extension (`io.modelcontextprotocol/skills`, SEP-2640).
+
+SEP-2640 defines a convention for serving Agent Skills over MCP using the
+Resources primitive: a skill is a directory of files, conventionally exposed
+under the `skill://` scheme, and enumerated and fetched through two required
+methods (`skills/list`, `skills/get`) plus one optional one
+(`resources/directory/read`). See
+https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2640.
+
+`Skills` is the protocol-level plumbing: request/response handling, SEP-2640
+conformance validation, and capability advertisement. A server author supplies
+handlers that answer `skills/list`/`skills/get`/`resources/directory/read`
+however their catalog is stored, and serves the underlying `skill://` file
+content through the server's ordinary resource-registration APIs.
+
+    async def list_skills(ctx, params):
+        return ListSkillsResult(skills=[...])
+
+    async def get_skill(ctx, params):
+        if params.uri != "skill://git-workflow/SKILL.md":
+            raise MCPError(code=INVALID_PARAMS, message="unknown skill")
+        return GetSkillResult(skill=...)
+
+    mcp = MCPServer("catalog", extensions=[Skills(list_skills=list_skills, get_skill=get_skill)])
+"""
+
+from mcp.server.skills._extension import Skills
+from mcp.server.skills.catalog import SkillCatalog
+from mcp.server.skills.filesystem import FilesystemSkillProvider
+from mcp.server.skills.provider import SkillProvider
+
+__all__ = ["Skills", "SkillCatalog", "SkillProvider", "FilesystemSkillProvider"]