fix(mcp): support fastmcp 3 and 4, parse adapter requests

sdk/CHANGELOG.md

@@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- MCP adapter reads tool schemas from fastmcp's own `Tool` instead of the
+  protocol `Tool`, so it works on fastmcp 3 and 4 without touching the
+  fields MCP SDK 2 renamed. The `mcp` extra now allows `fastmcp>=3,<5`.
+- MCP adapter subscriptions declare `data_type`, so handlers receive parsed
+  request models instead of raw dicts. Covered by a new end-to-end test.
 - `setup_tracing` type errors: exporter selection is typed, `endpoint` is
   passed explicitly, and the unused provider reassignment is gone.
 - A2A adapter type errors: `A2AConfig` imports `SecurityScheme`

sdk/eggai/adapters/mcp/mcp.py

@@ -29,6 +29,7 @@
 
     @agent.subscribe(
         channel=c("list.in"),
+        data_type=ToolListRequestMessage,
         auto_offset_reset="latest",
         group_id=name + "_tools_list_in",
     )
@@ -39,15 +40,11 @@
         mcp_tools = await mcp_server.list_tools()
         tools: list[ExternalTool] = []
         for tool in mcp_tools:
-            # fastmcp 3.x returns FunctionTool objects whose schemas live on
-            # `parameters`/`output_schema`; convert to the MCP protocol Tool to
-            # read the canonical `inputSchema`/`outputSchema` fields.
-            mcp_tool = tool.to_mcp_tool()
             external_tool = ExternalTool(
-                name=mcp_tool.name,
-                description=mcp_tool.description or "",
-                parameters=mcp_tool.inputSchema or {},
-                return_type=mcp_tool.outputSchema or {},
+                name=tool.name,
+                description=tool.description or "",
+                parameters=tool.parameters,
+                return_type=tool.output_schema or {},
             )
             tools.append(external_tool)
 
@@ -59,6 +56,7 @@
 
     @agent.subscribe(
         channel=c("calls.in"),
+        data_type=ToolCallRequestMessage,
         auto_offset_reset="latest",
         group_id=name + "_tool_calls_in",
     )