Extend resolver DI to sampling and roots requests (#3049)

docs_src/dependencies/tutorial004.py

@@ -0,0 +1,26 @@
+from typing import Annotated
+
+from mcp_types import CreateMessageResult, SamplingMessage, TextContent
+
+from mcp.server import MCPServer
+from mcp.server.mcpserver import Resolve, Sample
+
+mcp = MCPServer("Bookshop")
+
+
+def suggest_title(genre: str) -> Sample:
+    prompt = f"Suggest one {genre} book title. Answer with the title only."
+    return Sample(
+        [SamplingMessage(role="user", content=TextContent(type="text", text=prompt))],
+        max_tokens=50,
+    )
+
+
+@mcp.tool()
+async def recommend_book(
+    genre: str,
+    suggestion: Annotated[CreateMessageResult, Resolve(suggest_title)],
+) -> str:
+    """Recommend a book in the given genre."""
+    title = suggestion.content.text if suggestion.content.type == "text" else "the classics"
+    return f"Today's {genre} pick: {title}"