Make server can handle _meta field and send notification to client

Author: 134130

mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java

@@ -360,7 +360,7 @@ private McpServerSession.RequestHandler<CallToolResult> toolsCallRequestHandler(
 				return Mono.error(new McpError("Tool not found: " + callToolRequest.name()));
 			}
 
-			return toolSpecification.map(tool -> tool.call().apply(exchange, callToolRequest.arguments()))
+			return toolSpecification.map(tool -> tool.call().apply(exchange, callToolRequest))
 				.orElse(Mono.error(new McpError("Tool not found: " + callToolRequest.name())));
 		};
 	}

mcp/src/main/java/io/modelcontextprotocol/server/McpAsyncServerExchange.java

@@ -139,6 +139,16 @@ public Mono<McpSchema.ListRootsResult> listRoots(String cursor) {
 				LIST_ROOTS_RESULT_TYPE_REF);
 	}
 
+	public Mono<Void> notification(String method, Object params) {
+		if (method == null || method.isEmpty()) {
+			return Mono.error(new McpError("Method must not be null or empty"));
+		}
+		if (params == null) {
+			return Mono.error(new McpError("Params must not be null"));
+		}
+		return this.session.sendNotification(method, params);
+	}
+
 	/**
 	 * Send a logging message notification to all connected clients. Messages below the
 	 * current minimum logging level will be filtered out.

mcp/src/main/java/io/modelcontextprotocol/server/McpServer.java

@@ -309,7 +309,7 @@ public AsyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabi
 		 * Example usage: <pre>{@code
 		 * .tool(
 		 *     new Tool("calculator", "Performs calculations", schema),
-		 *     (exchange, args) -> Mono.fromSupplier(() -> calculate(args))
+		 *     (exchange, request) -> Mono.fromSupplier(() -> calculate(request))
 		 *         .map(result -> new CallToolResult("Result: " + result))
 		 * )
 		 * }</pre>
@@ -323,7 +323,7 @@ public AsyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabi
 		 * @throws IllegalArgumentException if tool or handler is null
 		 */
 		public AsyncSpecification tool(McpSchema.Tool tool,
-				BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<CallToolResult>> handler) {
+				BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<CallToolResult>> handler) {
 			Assert.notNull(tool, "Tool must not be null");
 			Assert.notNull(handler, "Handler must not be null");
 
@@ -801,7 +801,7 @@ public SyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabil
 		 * Example usage: <pre>{@code
 		 * .tool(
 		 *     new Tool("calculator", "Performs calculations", schema),
-		 *     (exchange, args) -> new CallToolResult("Result: " + calculate(args))
+		 *     (exchange, request) -> new CallToolResult("Result: " + calculate(request))
 		 * )
 		 * }</pre>
 		 * @param tool The tool definition including name, description, and schema. Must
@@ -814,7 +814,7 @@ public SyncSpecification capabilities(McpSchema.ServerCapabilities serverCapabil
 		 * @throws IllegalArgumentException if tool or handler is null
 		 */
 		public SyncSpecification tool(McpSchema.Tool tool,
-				BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> handler) {
+				BiFunction<McpSyncServerExchange, McpSchema.CallToolRequest, McpSchema.CallToolResult> handler) {
 			Assert.notNull(tool, "Tool must not be null");
 			Assert.notNull(handler, "Handler must not be null");
 

mcp/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java

@@ -222,8 +222,8 @@ record Sync(McpSchema.Implementation serverInfo, McpSchema.ServerCapabilities se
 	 *             .required("expression")
 	 *             .property("expression", JsonSchemaType.STRING)
 	 *     ),
-	 *     (exchange, args) -> {
-	 *         String expr = (String) args.get("expression");
+	 *     (exchange, request) -> {
+	 *         String expr = (String) request.arguments().get("expression");
 	 *         return Mono.fromSupplier(() -> evaluate(expr))
 	 *             .map(result -> new CallToolResult("Result: " + result));
 	 *     }
@@ -237,7 +237,7 @@ record Sync(McpSchema.Implementation serverInfo, McpSchema.ServerCapabilities se
 	 * connected client. The second arguments is a map of tool arguments.
 	 */
 	public record AsyncToolSpecification(McpSchema.Tool tool,
-			BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call) {
+			BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> call) {
 
 		static AsyncToolSpecification fromSync(SyncToolSpecification tool) {
 			// FIXME: This is temporary, proper validation should be implemented
@@ -413,7 +413,7 @@ static AsyncCompletionSpecification fromSync(SyncCompletionSpecification complet
 	 * client. The second arguments is a map of arguments passed to the tool.
 	 */
 	public record SyncToolSpecification(McpSchema.Tool tool,
-			BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call) {
+			BiFunction<McpSyncServerExchange, McpSchema.CallToolRequest, McpSchema.CallToolResult> call) {
 	}
 
 	/**

mcp/src/main/java/io/modelcontextprotocol/spec/McpSchema.java

@@ -783,6 +783,8 @@ private static JsonSchema parseSchema(String schema) {
 	 * tools/list.
 	 * @param arguments Arguments to pass to the tool. These must conform to the tool's
 	 * input schema.
+	 * @param _meta Optional metadata about the request. This can include additional
+	 * information like `progressToken`
 	 */
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	@JsonIgnoreProperties(ignoreUnknown = true)
@@ -1217,9 +1219,9 @@ public record PaginatedResult(@JsonProperty("nextCursor") String nextCursor) {
 	// ---------------------------
 
 	/**
-	 * The Model Context Protocol (MCP) supports optional progress tracking for long-running
-	 * operations through notification messages. Either side can send progress notifications
-	 * to provide updates about operation status.
+	 * The Model Context Protocol (MCP) supports optional progress tracking for
+	 * long-running operations through notification messages. Either side can send
+	 * progress notifications to provide updates about operation status.
 	 *
 	 * @param progressToken The original progress token
 	 * @param progress The current progress value so far