diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java b/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java
index 66e0b9d44..be4e4cf97 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientSseClientTransport.java
@@ -185,19 +185,6 @@ public static class Builder {
 			// Default constructor
 		}
 
-		/**
-		 * Creates a new builder with the specified base URI.
-		 * @param baseUri the base URI of the MCP server
-		 * @deprecated Use {@link HttpClientSseClientTransport#builder(String)} instead.
-		 * This constructor is deprecated and will be removed or made {@code protected} or
-		 * {@code private} in a future release.
-		 */
-		@Deprecated(forRemoval = true)
-		public Builder(String baseUri) {
-			Assert.hasText(baseUri, "baseUri must not be empty");
-			this.baseUri = baseUri;
-		}
-
 		/**
 		 * Sets the base URI.
 		 * @param baseUri the base URI
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/DefaultMcpStatelessServerHandler.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/DefaultMcpStatelessServerHandler.java
index d1b55f594..660a15e6a 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/DefaultMcpStatelessServerHandler.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/DefaultMcpStatelessServerHandler.java
@@ -32,7 +32,9 @@ public Mono<McpSchema.JSONRPCResponse> handleRequest(McpTransportContext transpo
 			McpSchema.JSONRPCRequest request) {
 		McpStatelessRequestHandler<?> requestHandler = this.requestHandlers.get(request.method());
 		if (requestHandler == null) {
-			return Mono.error(new McpError("Missing handler for request type: " + request.method()));
+			return Mono.error(McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND)
+				.message("Missing handler for request type: " + request.method())
+				.build());
 		}
 		return requestHandler.handle(transportContext, request.params())
 			.map(result -> new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(), result, null))
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
index 23285d514..32256987a 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServer.java
@@ -326,7 +326,7 @@ public Mono<Void> addTool(McpServerFeatures.AsyncToolSpecification toolSpecifica
 		if (toolSpecification.tool() == null) {
 			return Mono.error(new IllegalArgumentException("Tool must not be null"));
 		}
-		if (toolSpecification.call() == null && toolSpecification.callHandler() == null) {
+		if (toolSpecification.callHandler() == null) {
 			return Mono.error(new IllegalArgumentException("Tool call handler must not be null"));
 		}
 		if (this.serverCapabilities.tools() == null) {
@@ -869,32 +869,6 @@ private McpRequestHandler<McpSchema.GetPromptResult> promptsGetRequestHandler()
 	// Logging Management
 	// ---------------------------------------
 
-	/**
-	 * This implementation would, incorrectly, broadcast the logging message to all
-	 * connected clients, using a single minLoggingLevel for all of them. Similar to the
-	 * sampling and roots, the logging level should be set per client session and use the
-	 * ServerExchange to send the logging message to the right client.
-	 * @param loggingMessageNotification The logging message to send
-	 * @return A Mono that completes when the notification has been sent
-	 * @deprecated Use
-	 * {@link McpAsyncServerExchange#loggingNotification(LoggingMessageNotification)}
-	 * instead.
-	 */
-	@Deprecated
-	public Mono<Void> loggingNotification(LoggingMessageNotification loggingMessageNotification) {
-
-		if (loggingMessageNotification == null) {
-			return Mono.error(new McpError("Logging message must not be null"));
-		}
-
-		if (loggingMessageNotification.level().level() < minLoggingLevel.level()) {
-			return Mono.empty();
-		}
-
-		return this.mcpTransportProvider.notifyClients(McpSchema.METHOD_NOTIFICATION_MESSAGE,
-				loggingMessageNotification);
-	}
-
 	private McpRequestHandler<Object> setLoggerRequestHandler() {
 		return (exchange, params) -> {
 			return Mono.defer(() -> {
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServerExchange.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServerExchange.java
index a15c58cd5..40a76045b 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServerExchange.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpAsyncServerExchange.java
@@ -49,28 +49,6 @@ public class McpAsyncServerExchange {
 	public static final TypeRef<Object> OBJECT_TYPE_REF = new TypeRef<>() {
 	};
 
-	/**
-	 * Create a new asynchronous exchange with the client.
-	 * @param session The server session representing a 1-1 interaction.
-	 * @param clientCapabilities The client capabilities that define the supported
-	 * features and functionality.
-	 * @param clientInfo The client implementation information.
-	 * @deprecated Use
-	 * {@link #McpAsyncServerExchange(String, McpLoggableSession, McpSchema.ClientCapabilities, McpSchema.Implementation, McpTransportContext)}
-	 */
-	@Deprecated
-	public McpAsyncServerExchange(McpSession session, McpSchema.ClientCapabilities clientCapabilities,
-			McpSchema.Implementation clientInfo) {
-		this.sessionId = null;
-		if (!(session instanceof McpLoggableSession)) {
-			throw new IllegalArgumentException("Expecting session to be a McpLoggableSession instance");
-		}
-		this.session = (McpLoggableSession) session;
-		this.clientCapabilities = clientCapabilities;
-		this.clientInfo = clientInfo;
-		this.transportContext = McpTransportContext.EMPTY;
-	}
-
 	/**
 	 * Create a new asynchronous exchange with the client.
 	 * @param session The server session representing a 1-1 interaction.
@@ -142,10 +120,11 @@ public String sessionId() {
 	 */
 	public Mono<McpSchema.CreateMessageResult> createMessage(McpSchema.CreateMessageRequest createMessageRequest) {
 		if (this.clientCapabilities == null) {
-			return Mono.error(new McpError("Client must be initialized. Call the initialize method first!"));
+			return Mono
+				.error(new IllegalStateException("Client must be initialized. Call the initialize method first!"));
 		}
 		if (this.clientCapabilities.sampling() == null) {
-			return Mono.error(new McpError("Client must be configured with sampling capabilities"));
+			return Mono.error(new IllegalStateException("Client must be configured with sampling capabilities"));
 		}
 		return this.session.sendRequest(McpSchema.METHOD_SAMPLING_CREATE_MESSAGE, createMessageRequest,
 				CREATE_MESSAGE_RESULT_TYPE_REF);
@@ -167,10 +146,11 @@ public Mono<McpSchema.CreateMessageResult> createMessage(McpSchema.CreateMessage
 	 */
 	public Mono<McpSchema.ElicitResult> createElicitation(McpSchema.ElicitRequest elicitRequest) {
 		if (this.clientCapabilities == null) {
-			return Mono.error(new McpError("Client must be initialized. Call the initialize method first!"));
+			return Mono
+				.error(new IllegalStateException("Client must be initialized. Call the initialize method first!"));
 		}
 		if (this.clientCapabilities.elicitation() == null) {
-			return Mono.error(new McpError("Client must be configured with elicitation capabilities"));
+			return Mono.error(new IllegalStateException("Client must be configured with elicitation capabilities"));
 		}
 		return this.session.sendRequest(McpSchema.METHOD_ELICITATION_CREATE, elicitRequest,
 				ELICITATION_RESULT_TYPE_REF);
@@ -215,7 +195,7 @@ public Mono<McpSchema.ListRootsResult> listRoots(String cursor) {
 	public Mono<Void> loggingNotification(LoggingMessageNotification loggingMessageNotification) {
 
 		if (loggingMessageNotification == null) {
-			return Mono.error(new McpError("Logging message must not be null"));
+			return Mono.error(new IllegalStateException("Logging message must not be null"));
 		}
 
 		return Mono.defer(() -> {
@@ -234,7 +214,7 @@ public Mono<Void> loggingNotification(LoggingMessageNotification loggingMessageN
 	 */
 	public Mono<Void> progressNotification(McpSchema.ProgressNotification progressNotification) {
 		if (progressNotification == null) {
-			return Mono.error(new McpError("Progress notification must not be null"));
+			return Mono.error(new IllegalStateException("Progress notification must not be null"));
 		}
 		return this.session.sendNotification(McpSchema.METHOD_NOTIFICATION_PROGRESS, progressNotification);
 	}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServer.java
index 7fe9ef2a2..360eb607d 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServer.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServer.java
@@ -66,9 +66,9 @@
  * Example of creating a basic synchronous server: <pre>{@code
  * McpServer.sync(transportProvider)
  *     .serverInfo("my-server", "1.0.0")
- *     .tool(Tool.builder().name("calculator").title("Performs calculations").inputSchema(schema).build(),
- *           (exchange, args) -> CallToolResult.builder()
- *                   .content(List.of(new McpSchema.TextContent("Result: " + calculate(args))))
+ *     .toolCall(Tool.builder().name("calculator").title("Performs calculations").inputSchema(schema).build(),
+ *           (exchange, request) -> CallToolResult.builder()
+ *                   .content(List.of(new McpSchema.TextContent("Result: " + calculate(request.arguments()))))
  *                   .isError(false)
  *                   .build())
  *     .build();
@@ -77,8 +77,8 @@
  * Example of creating a basic asynchronous server: <pre>{@code
  * McpServer.async(transportProvider)
  *     .serverInfo("my-server", "1.0.0")
- *     .tool(Tool.builder().name("calculator").title("Performs calculations").inputSchema(schema).build(),
- *           (exchange, args) -> Mono.fromSupplier(() -> calculate(args))
+ *     .toolCall(Tool.builder().name("calculator").title("Performs calculations").inputSchema(schema).build(),
+ *           (exchange, request) -> Mono.fromSupplier(() -> calculate(request.arguments()))
  *               .map(result -> CallToolResult.builder()
  *                   .content(List.of(new McpSchema.TextContent("Result: " + result)))
  *                   .isError(false)
@@ -441,46 +441,6 @@ public AsyncSpecification<S> capabilities(McpSchema.ServerCapabilities serverCap
 			return this;
 		}
 
-		/**
-		 * Adds a single tool with its implementation handler to the server. This is a
-		 * convenience method for registering individual tools without creating a
-		 * {@link McpServerFeatures.AsyncToolSpecification} explicitly.
-		 *
-		 * <p>
-		 * Example usage: <pre>{@code
-		 * .tool(
-		 *     Tool.builder().name("calculator").title("Performs calculations").inputSchema(schema).build(),
-		 *     (exchange, args) -> Mono.fromSupplier(() -> calculate(args))
-		 *         .map(result -> CallToolResult.builder()
-		 *                   .content(List.of(new McpSchema.TextContent("Result: " + result)))
-		 *                   .isError(false)
-		 *                   .build()))
-		 * )
-		 * }</pre>
-		 * @param tool The tool definition including name, description, and schema. Must
-		 * not be null.
-		 * @param handler The function that implements the tool's logic. Must not be null.
-		 * The function's first argument is an {@link McpAsyncServerExchange} upon which
-		 * the server can interact with the connected client. The second argument is the
-		 * map of arguments passed to the tool.
-		 * @return This builder instance for method chaining
-		 * @throws IllegalArgumentException if tool or handler is null
-		 * @deprecated Use {@link #toolCall(McpSchema.Tool, BiFunction)} instead for tool
-		 * calls that require a request object.
-		 */
-		@Deprecated
-		public AsyncSpecification<S> tool(McpSchema.Tool tool,
-				BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<CallToolResult>> handler) {
-			Assert.notNull(tool, "Tool must not be null");
-			Assert.notNull(handler, "Handler must not be null");
-			validateToolName(tool.name());
-			assertNoDuplicateTool(tool.name());
-
-			this.tools.add(new McpServerFeatures.AsyncToolSpecification(tool, handler));
-
-			return this;
-		}
-
 		/**
 		 * Adds a single tool with its implementation handler to the server. This is a
 		 * convenience method for registering individual tools without creating a
@@ -1064,45 +1024,6 @@ public SyncSpecification<S> capabilities(McpSchema.ServerCapabilities serverCapa
 			return this;
 		}
 
-		/**
-		 * Adds a single tool with its implementation handler to the server. This is a
-		 * convenience method for registering individual tools without creating a
-		 * {@link McpServerFeatures.SyncToolSpecification} explicitly.
-		 *
-		 * <p>
-		 * Example usage: <pre>{@code
-		 * .tool(
-		 *     Tool.builder().name("calculator").title("Performs calculations".inputSchema(schema).build(),
-		 *     (exchange, args) -> CallToolResult.builder()
-		 *                   .content(List.of(new McpSchema.TextContent("Result: " + calculate(args))))
-		 *                   .isError(false)
-		 *                   .build())
-		 * )
-		 * }</pre>
-		 * @param tool The tool definition including name, description, and schema. Must
-		 * not be null.
-		 * @param handler The function that implements the tool's logic. Must not be null.
-		 * The function's first argument is an {@link McpSyncServerExchange} upon which
-		 * the server can interact with the connected client. The second argument is the
-		 * list of arguments passed to the tool.
-		 * @return This builder instance for method chaining
-		 * @throws IllegalArgumentException if tool or handler is null
-		 * @deprecated Use {@link #toolCall(McpSchema.Tool, BiFunction)} instead for tool
-		 * calls that require a request object.
-		 */
-		@Deprecated
-		public SyncSpecification<S> tool(McpSchema.Tool tool,
-				BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> handler) {
-			Assert.notNull(tool, "Tool must not be null");
-			Assert.notNull(handler, "Handler must not be null");
-			validateToolName(tool.name());
-			assertNoDuplicateTool(tool.name());
-
-			this.tools.add(new McpServerFeatures.SyncToolSpecification(tool, handler));
-
-			return this;
-		}
-
 		/**
 		 * Adds a single tool with its implementation handler to the server. This is a
 		 * convenience method for registering individual tools without creating a
@@ -1123,7 +1044,7 @@ public SyncSpecification<S> toolCall(McpSchema.Tool tool,
 			validateToolName(tool.name());
 			assertNoDuplicateTool(tool.name());
 
-			this.tools.add(new McpServerFeatures.SyncToolSpecification(tool, null, handler));
+			this.tools.add(new McpServerFeatures.SyncToolSpecification(tool, handler));
 
 			return this;
 		}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
index fe0608b1c..a0cbae0f2 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpServerFeatures.java
@@ -223,19 +223,8 @@ record Sync(McpSchema.Implementation serverInfo, McpSchema.ServerCapabilities se
 	 * map of tool arguments.
 	 */
 	public record AsyncToolSpecification(McpSchema.Tool tool,
-			@Deprecated BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call,
 			BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> callHandler) {
 
-		/**
-		 * @deprecated Use {@link AsyncToolSpecification(McpSchema.Tool, null,
-		 * BiFunction)} instead.
-		 **/
-		@Deprecated
-		public AsyncToolSpecification(McpSchema.Tool tool,
-				BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> call) {
-			this(tool, call, (exchange, toolReq) -> call.apply(exchange, toolReq.arguments()));
-		}
-
 		static AsyncToolSpecification fromSync(SyncToolSpecification syncToolSpec) {
 			return fromSync(syncToolSpec, false);
 		}
@@ -247,13 +236,6 @@ static AsyncToolSpecification fromSync(SyncToolSpecification syncToolSpec, boole
 				return null;
 			}
 
-			BiFunction<McpAsyncServerExchange, Map<String, Object>, Mono<McpSchema.CallToolResult>> deprecatedCall = (syncToolSpec
-				.call() != null) ? (exchange, map) -> {
-					var toolResult = Mono
-						.fromCallable(() -> syncToolSpec.call().apply(new McpSyncServerExchange(exchange), map));
-					return immediate ? toolResult : toolResult.subscribeOn(Schedulers.boundedElastic());
-				} : null;
-
 			BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> callHandler = (
 					exchange, req) -> {
 				var toolResult = Mono
@@ -261,7 +243,7 @@ static AsyncToolSpecification fromSync(SyncToolSpecification syncToolSpec, boole
 				return immediate ? toolResult : toolResult.subscribeOn(Schedulers.boundedElastic());
 			};
 
-			return new AsyncToolSpecification(syncToolSpec.tool(), deprecatedCall, callHandler);
+			return new AsyncToolSpecification(syncToolSpec.tool(), callHandler);
 		}
 
 		/**
@@ -304,7 +286,7 @@ public AsyncToolSpecification build() {
 				Assert.notNull(tool, "Tool must not be null");
 				Assert.notNull(callHandler, "Call handler function must not be null");
 
-				return new AsyncToolSpecification(tool, null, callHandler);
+				return new AsyncToolSpecification(tool, callHandler);
 			}
 
 		}
@@ -523,26 +505,16 @@ static AsyncCompletionSpecification fromSync(SyncCompletionSpecification complet
 	 * }</pre>
 	 *
 	 * @param tool The tool definition including name, description, and parameter schema
-	 * @param call (Deprected) The function that implements the tool's logic, receiving
-	 * arguments and returning results. The function's first argument is an
-	 * {@link McpSyncServerExchange} upon which the server can interact with the connected
 	 * @param callHandler The function that implements the tool's logic, receiving a
 	 * {@link McpSyncServerExchange} and a
 	 * {@link io.modelcontextprotocol.spec.McpSchema.CallToolRequest} and returning
 	 * results. The function's first argument is an {@link McpSyncServerExchange} upon
-	 * which the server can interact with the client. The second arguments is a map of
-	 * arguments passed to the tool.
+	 * which the server can interact with the client. The second argument is a request
+	 * object containing the arguments passed to the tool.
 	 */
 	public record SyncToolSpecification(McpSchema.Tool tool,
-			@Deprecated BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call,
 			BiFunction<McpSyncServerExchange, CallToolRequest, McpSchema.CallToolResult> callHandler) {
 
-		@Deprecated
-		public SyncToolSpecification(McpSchema.Tool tool,
-				BiFunction<McpSyncServerExchange, Map<String, Object>, McpSchema.CallToolResult> call) {
-			this(tool, call, (exchange, toolReq) -> call.apply(exchange, toolReq.arguments()));
-		}
-
 		/**
 		 * Builder for creating SyncToolSpecification instances.
 		 */
@@ -583,7 +555,7 @@ public SyncToolSpecification build() {
 				Assert.notNull(tool, "Tool must not be null");
 				Assert.notNull(callHandler, "CallTool function must not be null");
 
-				return new SyncToolSpecification(tool, null, callHandler);
+				return new SyncToolSpecification(tool, callHandler);
 			}
 
 		}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
index 10f0e5a31..d33299d02 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/McpSyncServer.java
@@ -230,21 +230,6 @@ public void notifyPromptsListChanged() {
 		this.asyncServer.notifyPromptsListChanged().block();
 	}
 
-	/**
-	 * This implementation would, incorrectly, broadcast the logging message to all
-	 * connected clients, using a single minLoggingLevel for all of them. Similar to the
-	 * sampling and roots, the logging level should be set per client session and use the
-	 * ServerExchange to send the logging message to the right client.
-	 * @param loggingMessageNotification The logging message to send
-	 * @deprecated Use
-	 * {@link McpSyncServerExchange#loggingNotification(LoggingMessageNotification)}
-	 * instead.
-	 */
-	@Deprecated
-	public void loggingNotification(LoggingMessageNotification loggingMessageNotification) {
-		this.asyncServer.loggingNotification(loggingMessageNotification).block();
-	}
-
 	/**
 	 * Close the server gracefully.
 	 */
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java
index d84518778..7037ff293 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java
@@ -343,7 +343,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 			response.setContentType(APPLICATION_JSON);
 			response.setCharacterEncoding(UTF_8);
 			response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
-			String jsonError = jsonMapper.writeValueAsString(new McpError("Session ID missing in message endpoint"));
+			String jsonError = jsonMapper.writeValueAsString(McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND)
+				.message("Session ID missing in message endpoint")
+				.build());
 			PrintWriter writer = response.getWriter();
 			writer.write(jsonError);
 			writer.flush();
@@ -356,7 +358,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 			response.setContentType(APPLICATION_JSON);
 			response.setCharacterEncoding(UTF_8);
 			response.setStatus(HttpServletResponse.SC_NOT_FOUND);
-			String jsonError = jsonMapper.writeValueAsString(new McpError("Session not found: " + sessionId));
+			String jsonError = jsonMapper.writeValueAsString(McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+				.message("Session not found: " + sessionId)
+				.build());
 			PrintWriter writer = response.getWriter();
 			writer.write(jsonError);
 			writer.flush();
@@ -383,7 +387,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 		catch (Exception e) {
 			logger.error("Error processing message: {}", e.getMessage());
 			try {
-				McpError mcpError = new McpError(e.getMessage());
+				McpError mcpError = McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+					.message(e.getMessage())
+					.build();
 				response.setContentType(APPLICATION_JSON);
 				response.setCharacterEncoding(UTF_8);
 				response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStatelessServerTransport.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStatelessServerTransport.java
index af25df28e..047aeebe8 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStatelessServerTransport.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStatelessServerTransport.java
@@ -147,7 +147,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 		String accept = request.getHeader(ACCEPT);
 		if (accept == null || !(accept.contains(APPLICATION_JSON) && accept.contains(TEXT_EVENT_STREAM))) {
 			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
-					new McpError("Both application/json and text/event-stream required in Accept header"));
+					McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND)
+						.message("Both application/json and text/event-stream required in Accept header")
+						.build());
 			return;
 		}
 
@@ -180,7 +182,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 				catch (Exception e) {
 					logger.error("Failed to handle request: {}", e.getMessage());
 					this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-							new McpError("Failed to handle request: " + e.getMessage()));
+							McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+								.message("Failed to handle request: " + e.getMessage())
+								.build());
 				}
 			}
 			else if (message instanceof McpSchema.JSONRPCNotification jsonrpcNotification) {
@@ -193,22 +197,29 @@ else if (message instanceof McpSchema.JSONRPCNotification jsonrpcNotification) {
 				catch (Exception e) {
 					logger.error("Failed to handle notification: {}", e.getMessage());
 					this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-							new McpError("Failed to handle notification: " + e.getMessage()));
+							McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+								.message("Failed to handle notification: " + e.getMessage())
+								.build());
 				}
 			}
 			else {
 				this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
-						new McpError("The server accepts either requests or notifications"));
+						McpError.builder(McpSchema.ErrorCodes.INVALID_REQUEST)
+							.message("The server accepts either requests or notifications")
+							.build());
 			}
 		}
 		catch (IllegalArgumentException | IOException e) {
 			logger.error("Failed to deserialize message: {}", e.getMessage());
-			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST, new McpError("Invalid message format"));
+			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
+					McpError.builder(McpSchema.ErrorCodes.INVALID_REQUEST).message("Invalid message format").build());
 		}
 		catch (Exception e) {
 			logger.error("Unexpected error handling message: {}", e.getMessage());
 			this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-					new McpError("Unexpected error: " + e.getMessage()));
+					McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+						.message("Unexpected error: " + e.getMessage())
+						.build());
 		}
 	}
 
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java
index ccd1d1ccb..d7561188c 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java
@@ -282,7 +282,8 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response)
 
 		if (!badRequestErrors.isEmpty()) {
 			String combinedMessage = String.join("; ", badRequestErrors);
-			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST, new McpError(combinedMessage));
+			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
+					McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND).message(combinedMessage).build());
 			return;
 		}
 
@@ -430,7 +431,8 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 					&& jsonrpcRequest.method().equals(McpSchema.METHOD_INITIALIZE)) {
 				if (!badRequestErrors.isEmpty()) {
 					String combinedMessage = String.join("; ", badRequestErrors);
-					this.responseError(response, HttpServletResponse.SC_BAD_REQUEST, new McpError(combinedMessage));
+					this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
+							McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND).message(combinedMessage).build());
 					return;
 				}
 
@@ -460,7 +462,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 				catch (Exception e) {
 					logger.error("Failed to initialize session: {}", e.getMessage());
 					this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-							new McpError("Failed to initialize session: " + e.getMessage()));
+							McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+								.message("Failed to initialize session: " + e.getMessage())
+								.build());
 					return;
 				}
 			}
@@ -473,7 +477,8 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 
 			if (!badRequestErrors.isEmpty()) {
 				String combinedMessage = String.join("; ", badRequestErrors);
-				this.responseError(response, HttpServletResponse.SC_BAD_REQUEST, new McpError(combinedMessage));
+				this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
+						McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND).message(combinedMessage).build());
 				return;
 			}
 
@@ -481,7 +486,9 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
 
 			if (session == null) {
 				this.responseError(response, HttpServletResponse.SC_NOT_FOUND,
-						new McpError("Session not found: " + sessionId));
+						McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+							.message("Session not found: " + sessionId)
+							.build());
 				return;
 			}
 
@@ -523,19 +530,23 @@ else if (message instanceof McpSchema.JSONRPCRequest jsonrpcRequest) {
 			}
 			else {
 				this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-						new McpError("Unknown message type"));
+						McpError.builder(McpSchema.ErrorCodes.INVALID_REQUEST).message("Unknown message type").build());
 			}
 		}
 		catch (IllegalArgumentException | IOException e) {
 			logger.error("Failed to deserialize message: {}", e.getMessage());
 			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
-					new McpError("Invalid message format: " + e.getMessage()));
+					McpError.builder(McpSchema.ErrorCodes.INVALID_REQUEST)
+						.message("Invalid message format: " + e.getMessage())
+						.build());
 		}
 		catch (Exception e) {
 			logger.error("Error handling message: {}", e.getMessage());
 			try {
 				this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-						new McpError("Error processing message: " + e.getMessage()));
+						McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR)
+							.message("Error processing message: " + e.getMessage())
+							.build());
 			}
 			catch (IOException ex) {
 				logger.error(FAILED_TO_SEND_ERROR_RESPONSE, ex.getMessage());
@@ -584,7 +595,9 @@ protected void doDelete(HttpServletRequest request, HttpServletResponse response
 
 		if (request.getHeader(HttpHeaders.MCP_SESSION_ID) == null) {
 			this.responseError(response, HttpServletResponse.SC_BAD_REQUEST,
-					new McpError("Session ID required in mcp-session-id header"));
+					McpError.builder(McpSchema.ErrorCodes.METHOD_NOT_FOUND)
+						.message("Session ID required in mcp-session-id header")
+						.build());
 			return;
 		}
 
@@ -605,7 +618,7 @@ protected void doDelete(HttpServletRequest request, HttpServletResponse response
 			logger.error("Failed to delete session {}: {}", sessionId, e.getMessage());
 			try {
 				this.responseError(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
-						new McpError(e.getMessage()));
+						McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR).message(e.getMessage()).build());
 			}
 			catch (IOException ex) {
 				logger.error(FAILED_TO_SEND_ERROR_RESPONSE, ex.getMessage());
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/StdioServerTransportProvider.java b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/StdioServerTransportProvider.java
index 68be62931..d288ea3d6 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/StdioServerTransportProvider.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/StdioServerTransportProvider.java
@@ -98,7 +98,7 @@ public void setSessionFactory(McpServerSession.Factory sessionFactory) {
 	@Override
 	public Mono<Void> notifyClients(String method, Object params) {
 		if (this.session == null) {
-			return Mono.error(new McpError("No session to close"));
+			return Mono.error(new IllegalStateException("No session to close"));
 		}
 		return this.session.sendNotification(method, params)
 			.doOnError(e -> logger.error("Failed to send notification: {}", e.getMessage()));
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java
index 0ba7ab3b8..80b5ae246 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpClientSession.java
@@ -96,21 +96,6 @@ public interface NotificationHandler {
 
 	}
 
-	/**
-	 * Creates a new McpClientSession with the specified configuration and handlers.
-	 * @param requestTimeout Duration to wait for responses
-	 * @param transport Transport implementation for message exchange
-	 * @param requestHandlers Map of method names to request handlers
-	 * @param notificationHandlers Map of method names to notification handlers
-	 * @deprecated Use
-	 * {@link #McpClientSession(Duration, McpClientTransport, Map, Map, Function)}
-	 */
-	@Deprecated
-	public McpClientSession(Duration requestTimeout, McpClientTransport transport,
-			Map<String, RequestHandler<?>> requestHandlers, Map<String, NotificationHandler> notificationHandlers) {
-		this(requestTimeout, transport, requestHandlers, notificationHandlers, Function.identity());
-	}
-
 	/**
 	 * Creates a new McpClientSession with the specified configuration and handlers.
 	 * @param requestTimeout Duration to wait for responses
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpError.java b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpError.java
index d6e549fdc..a3e7890e6 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpError.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpError.java
@@ -27,11 +27,6 @@ public McpError(JSONRPCError jsonRpcError) {
 		this.jsonRpcError = jsonRpcError;
 	}
 
-	@Deprecated
-	public McpError(Object error) {
-		super(error.toString());
-	}
-
 	public JSONRPCError getJsonRpcError() {
 		return jsonRpcError;
 	}
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
index 97bde0b10..bb9cead7e 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpSchema.java
@@ -41,9 +41,6 @@ public final class McpSchema {
 	private McpSchema() {
 	}
 
-	@Deprecated
-	public static final String LATEST_PROTOCOL_VERSION = ProtocolVersions.MCP_2025_11_25;
-
 	public static final String JSONRPC_VERSION = "2.0";
 
 	public static final String FIRST_PAGE = null;
@@ -798,35 +795,6 @@ public record Resource( // @formatter:off
 		@JsonProperty("annotations") Annotations annotations,
 		@JsonProperty("_meta") Map<String, Object> meta) implements ResourceContent { // @formatter:on
 
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link Resource#builder()} instead.
-		 */
-		@Deprecated
-		public Resource(String uri, String name, String title, String description, String mimeType, Long size,
-				Annotations annotations) {
-			this(uri, name, title, description, mimeType, size, annotations, null);
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link Resource#builder()} instead.
-		 */
-		@Deprecated
-		public Resource(String uri, String name, String description, String mimeType, Long size,
-				Annotations annotations) {
-			this(uri, name, null, description, mimeType, size, annotations, null);
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link Resource#builder()} instead.
-		 */
-		@Deprecated
-		public Resource(String uri, String name, String description, String mimeType, Annotations annotations) {
-			this(uri, name, null, description, mimeType, null, annotations, null);
-		}
-
 		public static Builder builder() {
 			return new Builder();
 		}
@@ -1592,36 +1560,6 @@ public record CallToolResult( // @formatter:off
 		@JsonProperty("structuredContent") Object structuredContent,
 		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on
 
-		/**
-		 * @deprecated use the builder instead.
-		 */
-		@Deprecated
-		public CallToolResult(List<Content> content, Boolean isError) {
-			this(content, isError, (Object) null, null);
-		}
-
-		/**
-		 * @deprecated use the builder instead.
-		 */
-		@Deprecated
-		public CallToolResult(List<Content> content, Boolean isError, Map<String, Object> structuredContent) {
-			this(content, isError, structuredContent, null);
-		}
-
-		/**
-		 * Creates a new instance of {@link CallToolResult} with a string containing the
-		 * tool result.
-		 * @param content The content of the tool result. This will be mapped to a
-		 * one-sized list with a {@link TextContent} element.
-		 * @param isError If true, indicates that the tool execution failed and the
-		 * content contains error information. If false or absent, indicates successful
-		 * execution.
-		 */
-		@Deprecated
-		public CallToolResult(String content, Boolean isError) {
-			this(List.of(new TextContent(content)), isError, null);
-		}
-
 		/**
 		 * Creates a builder for {@link CallToolResult}.
 		 * @return a new builder instance
@@ -2619,33 +2557,6 @@ public TextContent(Annotations annotations, String text) {
 		public TextContent(String content) {
 			this(null, content, null);
 		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link TextContent#TextContent(Annotations, String)} instead.
-		 */
-		@Deprecated
-		public TextContent(List<Role> audience, Double priority, String content) {
-			this(audience != null || priority != null ? new Annotations(audience, priority) : null, content, null);
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link TextContent#annotations()} instead.
-		 */
-		@Deprecated
-		public List<Role> audience() {
-			return annotations == null ? null : annotations.audience();
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link TextContent#annotations()} instead.
-		 */
-		@Deprecated
-		public Double priority() {
-			return annotations == null ? null : annotations.priority();
-		}
 	}
 
 	/**
@@ -2668,34 +2579,6 @@ public record ImageContent( // @formatter:off
 		public ImageContent(Annotations annotations, String data, String mimeType) {
 			this(annotations, data, mimeType, null);
 		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link ImageContent#ImageContent(Annotations, String, String)} instead.
-		 */
-		@Deprecated
-		public ImageContent(List<Role> audience, Double priority, String data, String mimeType) {
-			this(audience != null || priority != null ? new Annotations(audience, priority) : null, data, mimeType,
-					null);
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link ImageContent#annotations()} instead.
-		 */
-		@Deprecated
-		public List<Role> audience() {
-			return annotations == null ? null : annotations.audience();
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link ImageContent#annotations()} instead.
-		 */
-		@Deprecated
-		public Double priority() {
-			return annotations == null ? null : annotations.priority();
-		}
 	}
 
 	/**
@@ -2742,34 +2625,6 @@ public record EmbeddedResource( // @formatter:off
 		public EmbeddedResource(Annotations annotations, ResourceContents resource) {
 			this(annotations, resource, null);
 		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link EmbeddedResource#EmbeddedResource(Annotations, ResourceContents)}
-		 * instead.
-		 */
-		@Deprecated
-		public EmbeddedResource(List<Role> audience, Double priority, ResourceContents resource) {
-			this(audience != null || priority != null ? new Annotations(audience, priority) : null, resource, null);
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link EmbeddedResource#annotations()} instead.
-		 */
-		@Deprecated
-		public List<Role> audience() {
-			return annotations == null ? null : annotations.audience();
-		}
-
-		/**
-		 * @deprecated Only exists for backwards-compatibility purposes. Use
-		 * {@link EmbeddedResource#annotations()} instead.
-		 */
-		@Deprecated
-		public Double priority() {
-			return annotations == null ? null : annotations.priority();
-		}
 	}
 
 	/**
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java
index 241f7d8b5..ecb1dafd8 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/spec/McpServerSession.java
@@ -86,34 +86,6 @@ public McpServerSession(String id, Duration requestTimeout, McpServerTransport t
 		this.notificationHandlers = notificationHandlers;
 	}
 
-	/**
-	 * Creates a new server session with the given parameters and the transport to use.
-	 * @param id session id
-	 * @param transport the transport to use
-	 * @param initHandler called when a
-	 * {@link io.modelcontextprotocol.spec.McpSchema.InitializeRequest} is received by the
-	 * server
-	 * @param initNotificationHandler called when a
-	 * {@link io.modelcontextprotocol.spec.McpSchema#METHOD_NOTIFICATION_INITIALIZED} is
-	 * received.
-	 * @param requestHandlers map of request handlers to use
-	 * @param notificationHandlers map of notification handlers to use
-	 * @deprecated Use
-	 * {@link #McpServerSession(String, Duration, McpServerTransport, McpInitRequestHandler, Map, Map)}
-	 */
-	@Deprecated
-	public McpServerSession(String id, Duration requestTimeout, McpServerTransport transport,
-			McpInitRequestHandler initHandler, InitNotificationHandler initNotificationHandler,
-			Map<String, McpRequestHandler<?>> requestHandlers,
-			Map<String, McpNotificationHandler> notificationHandlers) {
-		this.id = id;
-		this.requestTimeout = requestTimeout;
-		this.transport = transport;
-		this.initRequestHandler = initHandler;
-		this.requestHandlers = requestHandlers;
-		this.notificationHandlers = notificationHandlers;
-	}
-
 	/**
 	 * Retrieve the session id.
 	 * @return session id
@@ -355,23 +327,6 @@ public void close() {
 		this.transport.close();
 	}
 
-	/**
-	 * Request handler for the initialization request.
-	 *
-	 * @deprecated Use {@link McpInitRequestHandler}
-	 */
-	@Deprecated
-	public interface InitRequestHandler {
-
-		/**
-		 * Handles the initialization request.
-		 * @param initializeRequest the initialization request by the client
-		 * @return a Mono that will emit the result of the initialization
-		 */
-		Mono<McpSchema.InitializeResult> handle(McpSchema.InitializeRequest initializeRequest);
-
-	}
-
 	/**
 	 * Notification handler for the initialization notification from the client.
 	 */
@@ -385,46 +340,6 @@ public interface InitNotificationHandler {
 
 	}
 
-	/**
-	 * A handler for client-initiated notifications.
-	 *
-	 * @deprecated Use {@link McpNotificationHandler}
-	 */
-	@Deprecated
-	public interface NotificationHandler {
-
-		/**
-		 * Handles a notification from the client.
-		 * @param exchange the exchange associated with the client that allows calling
-		 * back to the connected client or inspecting its capabilities.
-		 * @param params the parameters of the notification.
-		 * @return a Mono that completes once the notification is handled.
-		 */
-		Mono<Void> handle(McpAsyncServerExchange exchange, Object params);
-
-	}
-
-	/**
-	 * A handler for client-initiated requests.
-	 *
-	 * @param <T> the type of the response that is expected as a result of handling the
-	 * request.
-	 * @deprecated Use {@link McpRequestHandler}
-	 */
-	@Deprecated
-	public interface RequestHandler<T> {
-
-		/**
-		 * Handles a request from the client.
-		 * @param exchange the exchange associated with the client that allows calling
-		 * back to the connected client or inspecting its capabilities.
-		 * @param params the parameters of the request.
-		 * @return a Mono that will emit the response to the request.
-		 */
-		Mono<T> handle(McpAsyncServerExchange exchange, Object params);
-
-	}
-
 	/**
 	 * Factory for creating server sessions which delegate to a provided 1:1 transport
 	 * with a connected client.
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java b/mcp-core/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
index f9fc41b7a..061a95e69 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
@@ -9,10 +9,10 @@
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
-import io.modelcontextprotocol.json.McpJsonDefaults;
 import io.modelcontextprotocol.json.TypeRef;
 import io.modelcontextprotocol.spec.McpClientTransport;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import io.modelcontextprotocol.spec.McpSchema.JSONRPCNotification;
 import io.modelcontextprotocol.spec.McpSchema.JSONRPCRequest;
 import reactor.core.publisher.Mono;
@@ -29,7 +29,7 @@ public class MockMcpClientTransport implements McpClientTransport {
 
 	private final BiConsumer<MockMcpClientTransport, McpSchema.JSONRPCMessage> interceptor;
 
-	private String protocolVersion = McpSchema.LATEST_PROTOCOL_VERSION;
+	private String protocolVersion = ProtocolVersions.MCP_2025_11_25;
 
 	public MockMcpClientTransport() {
 		this((t, msg) -> {
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java b/mcp-core/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java
index c16b06a45..897ae2ccc 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/server/AsyncToolSpecificationBuilderTest.java
@@ -56,7 +56,6 @@ void builderShouldCreateValidAsyncToolSpecification() {
 		assertThat(specification).isNotNull();
 		assertThat(specification.tool()).isEqualTo(tool);
 		assertThat(specification.callHandler()).isNotNull();
-		assertThat(specification.call()).isNull(); // deprecated field should be null
 	}
 
 	@Test
@@ -107,12 +106,8 @@ void builtSpecificationShouldExecuteCallToolCorrectly() {
 
 		McpServerFeatures.AsyncToolSpecification specification = McpServerFeatures.AsyncToolSpecification.builder()
 			.tool(tool)
-			.callHandler((exchange, request) -> {
-				return Mono.just(CallToolResult.builder()
-					.content(List.of(new TextContent(expectedResult)))
-					.isError(false)
-					.build());
-			})
+			.callHandler((exchange, request) -> Mono.just(
+					CallToolResult.builder().content(List.of(new TextContent(expectedResult))).isError(false).build()))
 			.build();
 
 		CallToolRequest request = new CallToolRequest("calculator", Map.of());
@@ -127,54 +122,6 @@ void builtSpecificationShouldExecuteCallToolCorrectly() {
 		}).verifyComplete();
 	}
 
-	@Test
-	@SuppressWarnings("deprecation")
-	void deprecatedConstructorShouldWorkCorrectly() {
-		Tool tool = McpSchema.Tool.builder()
-			.name("deprecated-tool")
-			.title("A deprecated tool")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-		String expectedResult = "deprecated result";
-
-		// Test the deprecated constructor that takes a 'call' function
-		McpServerFeatures.AsyncToolSpecification specification = new McpServerFeatures.AsyncToolSpecification(tool,
-				(exchange,
-						arguments) -> Mono.just(CallToolResult.builder()
-							.content(List.of(new TextContent(expectedResult)))
-							.isError(false)
-							.build()));
-
-		assertThat(specification).isNotNull();
-		assertThat(specification.tool()).isEqualTo(tool);
-		assertThat(specification.call()).isNotNull(); // deprecated field should be set
-		assertThat(specification.callHandler()).isNotNull(); // should be automatically
-																// created
-
-		// Test that the callTool function works (it should delegate to the call function)
-		CallToolRequest request = new CallToolRequest("deprecated-tool", Map.of("arg1", "value1"));
-		Mono<CallToolResult> resultMono = specification.callHandler().apply(null, request);
-
-		StepVerifier.create(resultMono).assertNext(result -> {
-			assertThat(result).isNotNull();
-			assertThat(result.content()).hasSize(1);
-			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
-			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
-			assertThat(result.isError()).isFalse();
-		}).verifyComplete();
-
-		// Test that the deprecated call function also works directly
-		Mono<CallToolResult> callResultMono = specification.call().apply(null, request.arguments());
-
-		StepVerifier.create(callResultMono).assertNext(result -> {
-			assertThat(result).isNotNull();
-			assertThat(result.content()).hasSize(1);
-			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
-			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
-			assertThat(result.isError()).isFalse();
-		}).verifyComplete();
-	}
-
 	@Test
 	void fromSyncShouldConvertSyncToolSpecificationCorrectly() {
 		Tool tool = McpSchema.Tool.builder()
@@ -200,8 +147,6 @@ void fromSyncShouldConvertSyncToolSpecificationCorrectly() {
 		assertThat(asyncSpec).isNotNull();
 		assertThat(asyncSpec.tool()).isEqualTo(tool);
 		assertThat(asyncSpec.callHandler()).isNotNull();
-		assertThat(asyncSpec.call()).isNull(); // should be null since sync spec doesn't
-												// have deprecated call
 
 		// Test that the converted async specification works correctly
 		CallToolRequest request = new CallToolRequest("sync-tool", Map.of("param", "value"));
@@ -216,59 +161,6 @@ void fromSyncShouldConvertSyncToolSpecificationCorrectly() {
 		}).verifyComplete();
 	}
 
-	@Test
-	@SuppressWarnings("deprecation")
-	void fromSyncShouldConvertSyncToolSpecificationWithDeprecatedCallCorrectly() {
-		Tool tool = McpSchema.Tool.builder()
-			.name("sync-deprecated-tool")
-			.title("A sync tool with deprecated call")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-		String expectedResult = "sync deprecated result";
-		McpAsyncServerExchange nullExchange = null; // Mock or create a suitable exchange
-													// if needed
-
-		// Create a sync tool specification using the deprecated constructor
-		McpServerFeatures.SyncToolSpecification syncSpec = new McpServerFeatures.SyncToolSpecification(tool,
-				(exchange, arguments) -> CallToolResult.builder()
-					.content(List.of(new TextContent(expectedResult)))
-					.isError(false)
-					.build());
-
-		// Convert to async using fromSync
-		McpServerFeatures.AsyncToolSpecification asyncSpec = McpServerFeatures.AsyncToolSpecification
-			.fromSync(syncSpec);
-
-		assertThat(asyncSpec).isNotNull();
-		assertThat(asyncSpec.tool()).isEqualTo(tool);
-		assertThat(asyncSpec.callHandler()).isNotNull();
-		assertThat(asyncSpec.call()).isNotNull(); // should be set since sync spec has
-													// deprecated call
-
-		// Test that the converted async specification works correctly via callTool
-		CallToolRequest request = new CallToolRequest("sync-deprecated-tool", Map.of("param", "value"));
-		Mono<CallToolResult> resultMono = asyncSpec.callHandler().apply(nullExchange, request);
-
-		StepVerifier.create(resultMono).assertNext(result -> {
-			assertThat(result).isNotNull();
-			assertThat(result.content()).hasSize(1);
-			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
-			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
-			assertThat(result.isError()).isFalse();
-		}).verifyComplete();
-
-		// Test that the deprecated call function also works
-		Mono<CallToolResult> callResultMono = asyncSpec.call().apply(nullExchange, request.arguments());
-
-		StepVerifier.create(callResultMono).assertNext(result -> {
-			assertThat(result).isNotNull();
-			assertThat(result.content()).hasSize(1);
-			assertThat(result.content().get(0)).isInstanceOf(TextContent.class);
-			assertThat(((TextContent) result.content().get(0)).text()).isEqualTo(expectedResult);
-			assertThat(result.isError()).isFalse();
-		}).verifyComplete();
-	}
-
 	@Test
 	void fromSyncShouldReturnNullWhenSyncSpecIsNull() {
 		assertThat(McpServerFeatures.AsyncToolSpecification.fromSync(null)).isNull();
@@ -302,7 +194,8 @@ void tearDown() {
 		void defaultShouldThrowOnInvalidName() {
 			Tool invalidTool = Tool.builder().name("invalid tool name").build();
 
-			assertThatThrownBy(() -> McpServer.async(transportProvider).tool(invalidTool, (exchange, args) -> null))
+			assertThatThrownBy(
+					() -> McpServer.async(transportProvider).toolCall(invalidTool, (exchange, request) -> null))
 				.isInstanceOf(IllegalArgumentException.class)
 				.hasMessageContaining("invalid characters");
 		}
@@ -312,7 +205,7 @@ void lenientDefaultShouldLogOnInvalidName() {
 			System.setProperty(ToolNameValidator.STRICT_VALIDATION_PROPERTY, "false");
 			Tool invalidTool = Tool.builder().name("invalid tool name").build();
 
-			assertThatCode(() -> McpServer.async(transportProvider).tool(invalidTool, (exchange, args) -> null))
+			assertThatCode(() -> McpServer.async(transportProvider).toolCall(invalidTool, (exchange, request) -> null))
 				.doesNotThrowAnyException();
 			assertThat(logAppender.list).hasSize(1);
 		}
@@ -323,7 +216,7 @@ void lenientConfigurationShouldLogOnInvalidName() {
 
 			assertThatCode(() -> McpServer.async(transportProvider)
 				.strictToolNameValidation(false)
-				.tool(invalidTool, (exchange, args) -> null)).doesNotThrowAnyException();
+				.toolCall(invalidTool, (exchange, request) -> null)).doesNotThrowAnyException();
 			assertThat(logAppender.list).hasSize(1);
 		}
 
@@ -334,7 +227,7 @@ void serverConfigurationShouldOverrideDefault() {
 
 			assertThatThrownBy(() -> McpServer.async(transportProvider)
 				.strictToolNameValidation(true)
-				.tool(invalidTool, (exchange, args) -> null)).isInstanceOf(IllegalArgumentException.class)
+				.toolCall(invalidTool, (exchange, request) -> null)).isInstanceOf(IllegalArgumentException.class)
 				.hasMessageContaining("invalid characters");
 		}
 
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/server/McpAsyncServerExchangeTests.java b/mcp-core/src/test/java/io/modelcontextprotocol/server/McpAsyncServerExchangeTests.java
index 640d34c9c..e6161a59f 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/server/McpAsyncServerExchangeTests.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/server/McpAsyncServerExchangeTests.java
@@ -215,7 +215,7 @@ void testGetClientInfo() {
 	@Test
 	void testLoggingNotificationWithNullMessage() {
 		StepVerifier.create(exchange.loggingNotification(null)).verifyErrorSatisfies(error -> {
-			assertThat(error).isInstanceOf(McpError.class).hasMessage("Logging message must not be null");
+			assertThat(error).isInstanceOf(IllegalStateException.class).hasMessage("Logging message must not be null");
 		});
 	}
 
@@ -301,7 +301,8 @@ void testLoggingNotificationWithSessionError() {
 	@Test
 	void testCreateElicitationWithNullCapabilities() {
 		// Given - Create exchange with null capabilities
-		McpAsyncServerExchange exchangeWithNullCapabilities = new McpAsyncServerExchange(mockSession, null, clientInfo);
+		McpAsyncServerExchange exchangeWithNullCapabilities = new McpAsyncServerExchange("testSessionId", mockSession,
+				null, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
 			.message("Please provide your name")
@@ -309,7 +310,7 @@ void testCreateElicitationWithNullCapabilities() {
 
 		StepVerifier.create(exchangeWithNullCapabilities.createElicitation(elicitRequest))
 			.verifyErrorSatisfies(error -> {
-				assertThat(error).isInstanceOf(McpError.class)
+				assertThat(error).isInstanceOf(IllegalStateException.class)
 					.hasMessage("Client must be initialized. Call the initialize method first!");
 			});
 
@@ -324,15 +325,15 @@ void testCreateElicitationWithoutElicitationCapabilities() {
 			.roots(true)
 			.build();
 
-		McpAsyncServerExchange exchangeWithoutElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithoutElicitation, clientInfo);
+		McpAsyncServerExchange exchangeWithoutElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithoutElicitation, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
 			.message("Please provide your name")
 			.build();
 
 		StepVerifier.create(exchangeWithoutElicitation.createElicitation(elicitRequest)).verifyErrorSatisfies(error -> {
-			assertThat(error).isInstanceOf(McpError.class)
+			assertThat(error).isInstanceOf(IllegalStateException.class)
 				.hasMessage("Client must be configured with elicitation capabilities");
 		});
 
@@ -348,8 +349,8 @@ void testCreateElicitationWithComplexRequest() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 
 		// Create a complex elicit request with schema
 		java.util.Map<String, Object> requestedSchema = new java.util.HashMap<>();
@@ -391,8 +392,8 @@ void testCreateElicitationWithDeclineAction() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
 			.message("Please provide sensitive information")
@@ -418,8 +419,8 @@ void testCreateElicitationWithCancelAction() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
 			.message("Please provide your information")
@@ -445,8 +446,8 @@ void testCreateElicitationWithSessionError() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange exchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
 			.message("Please provide your name")
@@ -467,7 +468,8 @@ void testCreateElicitationWithSessionError() {
 	@Test
 	void testCreateMessageWithNullCapabilities() {
 
-		McpAsyncServerExchange exchangeWithNullCapabilities = new McpAsyncServerExchange(mockSession, null, clientInfo);
+		McpAsyncServerExchange exchangeWithNullCapabilities = new McpAsyncServerExchange("testSessionId", mockSession,
+				null, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
 			.messages(Arrays
@@ -476,7 +478,7 @@ void testCreateMessageWithNullCapabilities() {
 
 		StepVerifier.create(exchangeWithNullCapabilities.createMessage(createMessageRequest))
 			.verifyErrorSatisfies(error -> {
-				assertThat(error).isInstanceOf(McpError.class)
+				assertThat(error).isInstanceOf(IllegalStateException.class)
 					.hasMessage("Client must be initialized. Call the initialize method first!");
 			});
 
@@ -492,8 +494,8 @@ void testCreateMessageWithoutSamplingCapabilities() {
 			.roots(true)
 			.build();
 
-		McpAsyncServerExchange exchangeWithoutSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithoutSampling, clientInfo);
+		McpAsyncServerExchange exchangeWithoutSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithoutSampling, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
 			.messages(Arrays
@@ -501,7 +503,7 @@ void testCreateMessageWithoutSamplingCapabilities() {
 			.build();
 
 		StepVerifier.create(exchangeWithoutSampling.createMessage(createMessageRequest)).verifyErrorSatisfies(error -> {
-			assertThat(error).isInstanceOf(McpError.class)
+			assertThat(error).isInstanceOf(IllegalStateException.class)
 				.hasMessage("Client must be configured with sampling capabilities");
 		});
 
@@ -517,8 +519,8 @@ void testCreateMessageWithBasicRequest() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange(mockSession, capabilitiesWithSampling,
-				clientInfo);
+		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
 			.messages(Arrays
@@ -553,8 +555,8 @@ void testCreateMessageWithImageContent() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange(mockSession, capabilitiesWithSampling,
-				clientInfo);
+		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 
 		// Create request with image content
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
@@ -588,8 +590,8 @@ void testCreateMessageWithSessionError() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange(mockSession, capabilitiesWithSampling,
-				clientInfo);
+		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
 			.messages(Arrays
@@ -612,8 +614,8 @@ void testCreateMessageWithIncludeContext() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange(mockSession, capabilitiesWithSampling,
-				clientInfo);
+		McpAsyncServerExchange exchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
 			.messages(Arrays.asList(new McpSchema.SamplingMessage(McpSchema.Role.USER,
@@ -662,7 +664,7 @@ void testPingWithSuccessfulResponse() {
 	@Test
 	void testPingWithMcpError() {
 		// Given - Mock an MCP-specific error during ping
-		McpError mcpError = new McpError("Server unavailable");
+		McpError mcpError = McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR).message("Server unavailable").build();
 		when(mockSession.sendRequest(eq(McpSchema.METHOD_PING), eq(null), any(TypeRef.class)))
 			.thenReturn(Mono.error(mcpError));
 
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/server/McpSyncServerExchangeTests.java b/mcp-core/src/test/java/io/modelcontextprotocol/server/McpSyncServerExchangeTests.java
index 069d0f896..fba733c9a 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/server/McpSyncServerExchangeTests.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/server/McpSyncServerExchangeTests.java
@@ -9,6 +9,7 @@
 import java.util.List;
 import java.util.Map;
 
+import io.modelcontextprotocol.common.McpTransportContext;
 import io.modelcontextprotocol.spec.McpError;
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpServerSession;
@@ -54,7 +55,8 @@ void setUp() {
 
 		clientInfo = new McpSchema.Implementation("test-client", "1.0.0");
 
-		asyncExchange = new McpAsyncServerExchange(mockSession, clientCapabilities, clientInfo);
+		asyncExchange = new McpAsyncServerExchange("testSessionId", mockSession, clientCapabilities, clientInfo,
+				McpTransportContext.EMPTY);
 		exchange = new McpSyncServerExchange(asyncExchange);
 	}
 
@@ -212,7 +214,7 @@ void testGetClientInfo() {
 
 	@Test
 	void testLoggingNotificationWithNullMessage() {
-		assertThatThrownBy(() -> exchange.loggingNotification(null)).isInstanceOf(McpError.class)
+		assertThatThrownBy(() -> exchange.loggingNotification(null)).isInstanceOf(IllegalStateException.class)
 			.hasMessage("Logging message must not be null");
 	}
 
@@ -294,8 +296,8 @@ void testLoggingNotificationWithSessionError() {
 	@Test
 	void testCreateElicitationWithNullCapabilities() {
 		// Given - Create exchange with null capabilities
-		McpAsyncServerExchange asyncExchangeWithNullCapabilities = new McpAsyncServerExchange(mockSession, null,
-				clientInfo);
+		McpAsyncServerExchange asyncExchangeWithNullCapabilities = new McpAsyncServerExchange("testSessionId",
+				mockSession, null, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithNullCapabilities = new McpSyncServerExchange(
 				asyncExchangeWithNullCapabilities);
 
@@ -304,7 +306,7 @@ void testCreateElicitationWithNullCapabilities() {
 			.build();
 
 		assertThatThrownBy(() -> exchangeWithNullCapabilities.createElicitation(elicitRequest))
-			.isInstanceOf(McpError.class)
+			.isInstanceOf(IllegalStateException.class)
 			.hasMessage("Client must be initialized. Call the initialize method first!");
 
 		// Verify that sendRequest was never called due to null capabilities
@@ -318,8 +320,8 @@ void testCreateElicitationWithoutElicitationCapabilities() {
 			.roots(true)
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithoutElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithoutElicitation, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithoutElicitation = new McpAsyncServerExchange("testSessionId",
+				mockSession, capabilitiesWithoutElicitation, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithoutElicitation = new McpSyncServerExchange(asyncExchangeWithoutElicitation);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
@@ -327,7 +329,7 @@ void testCreateElicitationWithoutElicitationCapabilities() {
 			.build();
 
 		assertThatThrownBy(() -> exchangeWithoutElicitation.createElicitation(elicitRequest))
-			.isInstanceOf(McpError.class)
+			.isInstanceOf(IllegalStateException.class)
 			.hasMessage("Client must be configured with elicitation capabilities");
 
 		// Verify that sendRequest was never called due to missing elicitation
@@ -342,8 +344,8 @@ void testCreateElicitationWithComplexRequest() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithElicitation = new McpSyncServerExchange(asyncExchangeWithElicitation);
 
 		// Create a complex elicit request with schema
@@ -386,8 +388,8 @@ void testCreateElicitationWithDeclineAction() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithElicitation = new McpSyncServerExchange(asyncExchangeWithElicitation);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
@@ -414,8 +416,8 @@ void testCreateElicitationWithCancelAction() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithElicitation = new McpSyncServerExchange(asyncExchangeWithElicitation);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
@@ -442,8 +444,8 @@ void testCreateElicitationWithSessionError() {
 			.elicitation()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithElicitation, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithElicitation = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithElicitation, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithElicitation = new McpSyncServerExchange(asyncExchangeWithElicitation);
 
 		McpSchema.ElicitRequest elicitRequest = McpSchema.ElicitRequest.builder()
@@ -465,8 +467,8 @@ void testCreateElicitationWithSessionError() {
 	@Test
 	void testCreateMessageWithNullCapabilities() {
 
-		McpAsyncServerExchange asyncExchangeWithNullCapabilities = new McpAsyncServerExchange(mockSession, null,
-				clientInfo);
+		McpAsyncServerExchange asyncExchangeWithNullCapabilities = new McpAsyncServerExchange("testSessionId",
+				mockSession, null, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithNullCapabilities = new McpSyncServerExchange(
 				asyncExchangeWithNullCapabilities);
 
@@ -476,7 +478,7 @@ void testCreateMessageWithNullCapabilities() {
 			.build();
 
 		assertThatThrownBy(() -> exchangeWithNullCapabilities.createMessage(createMessageRequest))
-			.isInstanceOf(McpError.class)
+			.isInstanceOf(IllegalStateException.class)
 			.hasMessage("Client must be initialized. Call the initialize method first!");
 
 		// Verify that sendRequest was never called due to null capabilities
@@ -491,8 +493,8 @@ void testCreateMessageWithoutSamplingCapabilities() {
 			.roots(true)
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithoutSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithoutSampling, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithoutSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithoutSampling, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithoutSampling = new McpSyncServerExchange(asyncExchangeWithoutSampling);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
@@ -501,7 +503,7 @@ void testCreateMessageWithoutSamplingCapabilities() {
 			.build();
 
 		assertThatThrownBy(() -> exchangeWithoutSampling.createMessage(createMessageRequest))
-			.isInstanceOf(McpError.class)
+			.isInstanceOf(IllegalStateException.class)
 			.hasMessage("Client must be configured with sampling capabilities");
 
 		// Verify that sendRequest was never called due to missing sampling capabilities
@@ -516,8 +518,8 @@ void testCreateMessageWithBasicRequest() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithSampling, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithSampling = new McpSyncServerExchange(asyncExchangeWithSampling);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
@@ -553,8 +555,8 @@ void testCreateMessageWithImageContent() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithSampling, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithSampling = new McpSyncServerExchange(asyncExchangeWithSampling);
 
 		// Create request with image content
@@ -589,8 +591,8 @@ void testCreateMessageWithSessionError() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithSampling, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithSampling = new McpSyncServerExchange(asyncExchangeWithSampling);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
@@ -614,8 +616,8 @@ void testCreateMessageWithIncludeContext() {
 			.sampling()
 			.build();
 
-		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange(mockSession,
-				capabilitiesWithSampling, clientInfo);
+		McpAsyncServerExchange asyncExchangeWithSampling = new McpAsyncServerExchange("testSessionId", mockSession,
+				capabilitiesWithSampling, clientInfo, McpTransportContext.EMPTY);
 		McpSyncServerExchange exchangeWithSampling = new McpSyncServerExchange(asyncExchangeWithSampling);
 
 		McpSchema.CreateMessageRequest createMessageRequest = McpSchema.CreateMessageRequest.builder()
@@ -662,7 +664,7 @@ void testPingWithSuccessfulResponse() {
 	@Test
 	void testPingWithMcpError() {
 		// Given - Mock an MCP-specific error during ping
-		McpError mcpError = new McpError("Server unavailable");
+		McpError mcpError = McpError.builder(McpSchema.ErrorCodes.INTERNAL_ERROR).message("Server unavailable").build();
 		when(mockSession.sendRequest(eq(McpSchema.METHOD_PING), eq(null), any(TypeRef.class)))
 			.thenReturn(Mono.error(mcpError));
 
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/server/ResourceTemplateListingTest.java b/mcp-core/src/test/java/io/modelcontextprotocol/server/ResourceTemplateListingTest.java
index 61703c306..993ca717e 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/server/ResourceTemplateListingTest.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/server/ResourceTemplateListingTest.java
@@ -41,10 +41,26 @@ void testTemplateResourcesFilteredFromRegularListing() {
 	void testResourceListingWithMixedResources() {
 		// Create resource list with both regular and template resources
 		List<McpSchema.Resource> allResources = List.of(
-				new McpSchema.Resource("file:///test/doc1.txt", "Document 1", "text/plain", null, null),
-				new McpSchema.Resource("file:///test/doc2.txt", "Document 2", "text/plain", null, null),
-				new McpSchema.Resource("file:///test/{type}/document.txt", "Typed Document", "text/plain", null, null),
-				new McpSchema.Resource("file:///users/{userId}/files/{fileId}", "User File", "text/plain", null, null));
+				McpSchema.Resource.builder()
+					.uri("file:///test/doc1.txt")
+					.name("Document 1")
+					.mimeType("text/plain")
+					.build(),
+				McpSchema.Resource.builder()
+					.uri("file:///test/doc2.txt")
+					.name("Document 2")
+					.mimeType("text/plain")
+					.build(),
+				McpSchema.Resource.builder()
+					.uri("file:///test/{type}/document.txt")
+					.name("Typed Document")
+					.mimeType("text/plain")
+					.build(),
+				McpSchema.Resource.builder()
+					.uri("file:///users/{userId}/files/{fileId}")
+					.name("User File")
+					.mimeType("text/plain")
+					.build());
 
 		// Apply the filter logic from McpAsyncServer line 438
 		List<McpSchema.Resource> filteredResources = allResources.stream()
@@ -61,9 +77,16 @@ void testResourceListingWithMixedResources() {
 	void testResourceTemplatesListedSeparately() {
 		// Create mixed resources
 		List<McpSchema.Resource> resources = List.of(
-				new McpSchema.Resource("file:///test/regular.txt", "Regular Resource", "text/plain", null, null),
-				new McpSchema.Resource("file:///test/user/{userId}/profile.txt", "User Profile", "text/plain", null,
-						null));
+				McpSchema.Resource.builder()
+					.uri("file:///test/regular.txt")
+					.name("Regular Resource")
+					.mimeType("text/plain")
+					.build(),
+				McpSchema.Resource.builder()
+					.uri("file:///test/user/{userId}/profile.txt")
+					.name("User Profile")
+					.mimeType("text/plain")
+					.build());
 
 		// Create explicit resource template
 		McpSchema.ResourceTemplate explicitTemplate = new McpSchema.ResourceTemplate(
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java b/mcp-core/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java
index a2030e468..54c45e561 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/server/SyncToolSpecificationBuilderTest.java
@@ -51,7 +51,6 @@ void builderShouldCreateValidSyncToolSpecification() {
 		assertThat(specification).isNotNull();
 		assertThat(specification.tool()).isEqualTo(tool);
 		assertThat(specification.callHandler()).isNotNull();
-		assertThat(specification.call()).isNull(); // deprecated field should be null
 	}
 
 	@Test
@@ -140,7 +139,8 @@ void tearDown() {
 		void defaultShouldThrowOnInvalidName() {
 			Tool invalidTool = Tool.builder().name("invalid tool name").build();
 
-			assertThatThrownBy(() -> McpServer.sync(transportProvider).tool(invalidTool, (exchange, args) -> null))
+			assertThatThrownBy(
+					() -> McpServer.sync(transportProvider).toolCall(invalidTool, (exchange, request) -> null))
 				.isInstanceOf(IllegalArgumentException.class)
 				.hasMessageContaining("invalid characters");
 		}
@@ -150,7 +150,7 @@ void lenientDefaultShouldLogOnInvalidName() {
 			System.setProperty(ToolNameValidator.STRICT_VALIDATION_PROPERTY, "false");
 			Tool invalidTool = Tool.builder().name("invalid tool name").build();
 
-			assertThatCode(() -> McpServer.sync(transportProvider).tool(invalidTool, (exchange, args) -> null))
+			assertThatCode(() -> McpServer.sync(transportProvider).toolCall(invalidTool, (exchange, request) -> null))
 				.doesNotThrowAnyException();
 			assertThat(logAppender.list).hasSize(1);
 		}
@@ -161,7 +161,7 @@ void lenientConfigurationShouldLogOnInvalidName() {
 
 			assertThatCode(() -> McpServer.sync(transportProvider)
 				.strictToolNameValidation(false)
-				.tool(invalidTool, (exchange, args) -> null)).doesNotThrowAnyException();
+				.toolCall(invalidTool, (exchange, request) -> null)).doesNotThrowAnyException();
 			assertThat(logAppender.list).hasSize(1);
 		}
 
@@ -172,7 +172,7 @@ void serverConfigurationShouldOverrideDefault() {
 
 			assertThatThrownBy(() -> McpServer.sync(transportProvider)
 				.strictToolNameValidation(true)
-				.tool(invalidTool, (exchange, args) -> null)).isInstanceOf(IllegalArgumentException.class)
+				.toolCall(invalidTool, (exchange, request) -> null)).isInstanceOf(IllegalArgumentException.class)
 				.hasMessageContaining("invalid characters");
 		}
 
diff --git a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapper.java b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapper.java
deleted file mode 100644
index 4c69e9d34..000000000
--- a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapper.java
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * Copyright 2025 - 2025 the original author or authors.
- */
-
-package io.modelcontextprotocol.json.jackson;
-
-import com.fasterxml.jackson.databind.JavaType;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import io.modelcontextprotocol.json.McpJsonMapper;
-import io.modelcontextprotocol.json.TypeRef;
-
-import java.io.IOException;
-
-/**
- * Jackson-based implementation of JsonMapper. Wraps a Jackson ObjectMapper but keeps the
- * SDK decoupled from Jackson at the API level.
- *
- * @deprecated since 18.0.0, use
- * {@link io.modelcontextprotocol.json.jackson2.JacksonMcpJsonMapper} instead. Will be
- * removed in 19.0.0
- */
-@Deprecated(forRemoval = true, since = "18.0.0")
-public final class JacksonMcpJsonMapper implements McpJsonMapper {
-
-	private final ObjectMapper objectMapper;
-
-	/**
-	 * Constructs a new JacksonMcpJsonMapper instance with the given ObjectMapper.
-	 * @param objectMapper the ObjectMapper to be used for JSON serialization and
-	 * deserialization. Must not be null.
-	 * @throws IllegalArgumentException if the provided ObjectMapper is null.
-	 */
-	public JacksonMcpJsonMapper(ObjectMapper objectMapper) {
-		if (objectMapper == null) {
-			throw new IllegalArgumentException("ObjectMapper must not be null");
-		}
-		this.objectMapper = objectMapper;
-	}
-
-	/**
-	 * Returns the underlying Jackson {@link ObjectMapper} used for JSON serialization and
-	 * deserialization.
-	 * @return the ObjectMapper instance
-	 */
-	public ObjectMapper getObjectMapper() {
-		return objectMapper;
-	}
-
-	@Override
-	public <T> T readValue(String content, Class<T> type) throws IOException {
-		return objectMapper.readValue(content, type);
-	}
-
-	@Override
-	public <T> T readValue(byte[] content, Class<T> type) throws IOException {
-		return objectMapper.readValue(content, type);
-	}
-
-	@Override
-	public <T> T readValue(String content, TypeRef<T> type) throws IOException {
-		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
-		return objectMapper.readValue(content, javaType);
-	}
-
-	@Override
-	public <T> T readValue(byte[] content, TypeRef<T> type) throws IOException {
-		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
-		return objectMapper.readValue(content, javaType);
-	}
-
-	@Override
-	public <T> T convertValue(Object fromValue, Class<T> type) {
-		return objectMapper.convertValue(fromValue, type);
-	}
-
-	@Override
-	public <T> T convertValue(Object fromValue, TypeRef<T> type) {
-		JavaType javaType = objectMapper.getTypeFactory().constructType(type.getType());
-		return objectMapper.convertValue(fromValue, javaType);
-	}
-
-	@Override
-	public String writeValueAsString(Object value) throws IOException {
-		return objectMapper.writeValueAsString(value);
-	}
-
-	@Override
-	public byte[] writeValueAsBytes(Object value) throws IOException {
-		return objectMapper.writeValueAsBytes(value);
-	}
-
-}
diff --git a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapperSupplier.java b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapperSupplier.java
deleted file mode 100644
index 8a7c0f42a..000000000
--- a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/jackson/JacksonMcpJsonMapperSupplier.java
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Copyright 2025 - 2025 the original author or authors.
- */
-
-package io.modelcontextprotocol.json.jackson;
-
-import io.modelcontextprotocol.json.McpJsonMapper;
-import io.modelcontextprotocol.json.McpJsonMapperSupplier;
-
-/**
- * A supplier of {@link McpJsonMapper} instances that uses the Jackson library for JSON
- * serialization and deserialization.
- * <p>
- * This implementation provides a {@link McpJsonMapper} backed by a Jackson
- * {@link com.fasterxml.jackson.databind.ObjectMapper}.
- *
- * @deprecated since 18.0.0, use
- * {@link io.modelcontextprotocol.json.jackson2.JacksonMcpJsonMapperSupplier} instead.
- * Will be removed in 19.0.0.
- */
-@Deprecated(forRemoval = true, since = "18.0.0")
-public class JacksonMcpJsonMapperSupplier implements McpJsonMapperSupplier {
-
-	/**
-	 * Returns a new instance of {@link McpJsonMapper} that uses the Jackson library for
-	 * JSON serialization and deserialization.
-	 * <p>
-	 * The returned {@link McpJsonMapper} is backed by a new instance of
-	 * {@link com.fasterxml.jackson.databind.ObjectMapper}.
-	 * @return a new {@link McpJsonMapper} instance
-	 */
-	@Override
-	public McpJsonMapper get() {
-		return new JacksonMcpJsonMapper(new com.fasterxml.jackson.databind.ObjectMapper());
-	}
-
-}
diff --git a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/DefaultJsonSchemaValidator.java b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/DefaultJsonSchemaValidator.java
deleted file mode 100644
index 002a9d2a9..000000000
--- a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/DefaultJsonSchemaValidator.java
+++ /dev/null
@@ -1,165 +0,0 @@
-/*
- * Copyright 2024-2024 the original author or authors.
- */
-package io.modelcontextprotocol.json.schema.jackson;
-
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.networknt.schema.Schema;
-import com.networknt.schema.SchemaRegistry;
-import com.networknt.schema.Error;
-import com.networknt.schema.dialect.Dialects;
-import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Default implementation of the {@link JsonSchemaValidator} interface. This class
- * provides methods to validate structured content against a JSON schema. It uses the
- * NetworkNT JSON Schema Validator library for validation.
- *
- * @author Christian Tzolov
- * @deprecated since 18.0.0, use
- * {@link io.modelcontextprotocol.json.schema.jackson2.DefaultJsonSchemaValidator}
- * instead. Will be removed in 19.0.0.
- */
-@Deprecated(forRemoval = true, since = "18.0.0")
-public class DefaultJsonSchemaValidator implements JsonSchemaValidator {
-
-	private static final Logger logger = LoggerFactory.getLogger(DefaultJsonSchemaValidator.class);
-
-	private final ObjectMapper objectMapper;
-
-	private final SchemaRegistry schemaFactory;
-
-	// TODO: Implement a strategy to purge the cache (TTL, size limit, etc.)
-	private final ConcurrentHashMap<String, Schema> schemaCache;
-
-	public DefaultJsonSchemaValidator() {
-		this(new ObjectMapper());
-	}
-
-	public DefaultJsonSchemaValidator(ObjectMapper objectMapper) {
-		this.objectMapper = objectMapper;
-		this.schemaFactory = SchemaRegistry.withDialect(Dialects.getDraft202012());
-		this.schemaCache = new ConcurrentHashMap<>();
-	}
-
-	@Override
-	public ValidationResponse validate(Map<String, Object> schema, Object structuredContent) {
-
-		if (schema == null) {
-			throw new IllegalArgumentException("Schema must not be null");
-		}
-		if (structuredContent == null) {
-			throw new IllegalArgumentException("Structured content must not be null");
-		}
-
-		try {
-
-			JsonNode jsonStructuredOutput = (structuredContent instanceof String)
-					? this.objectMapper.readTree((String) structuredContent)
-					: this.objectMapper.valueToTree(structuredContent);
-
-			List<Error> validationResult = this.getOrCreateJsonSchema(schema).validate(jsonStructuredOutput);
-
-			// Check if validation passed
-			if (!validationResult.isEmpty()) {
-				return ValidationResponse
-					.asInvalid("Validation failed: structuredContent does not match tool outputSchema. "
-							+ "Validation errors: " + validationResult);
-			}
-
-			return ValidationResponse.asValid(jsonStructuredOutput.toString());
-
-		}
-		catch (JsonProcessingException e) {
-			logger.error("Failed to validate CallToolResult: Error parsing schema: {}", e);
-			return ValidationResponse.asInvalid("Error parsing tool JSON Schema: " + e.getMessage());
-		}
-		catch (Exception e) {
-			logger.error("Failed to validate CallToolResult: Unexpected error: {}", e);
-			return ValidationResponse.asInvalid("Unexpected validation error: " + e.getMessage());
-		}
-	}
-
-	/**
-	 * Gets a cached Schema or creates and caches a new one.
-	 * @param schema the schema map to convert
-	 * @return the compiled Schema
-	 * @throws JsonProcessingException if schema processing fails
-	 */
-	private Schema getOrCreateJsonSchema(Map<String, Object> schema) throws JsonProcessingException {
-		// Generate cache key based on schema content
-		String cacheKey = this.generateCacheKey(schema);
-
-		// Try to get from cache first
-		Schema cachedSchema = this.schemaCache.get(cacheKey);
-		if (cachedSchema != null) {
-			return cachedSchema;
-		}
-
-		// Create new schema if not in cache
-		Schema newSchema = this.createJsonSchema(schema);
-
-		// Cache the schema
-		Schema existingSchema = this.schemaCache.putIfAbsent(cacheKey, newSchema);
-		return existingSchema != null ? existingSchema : newSchema;
-	}
-
-	/**
-	 * Creates a new Schema from the given schema map.
-	 * @param schema the schema map
-	 * @return the compiled Schema
-	 * @throws JsonProcessingException if schema processing fails
-	 */
-	private Schema createJsonSchema(Map<String, Object> schema) throws JsonProcessingException {
-		// Convert schema map directly to JsonNode (more efficient than string
-		// serialization)
-		JsonNode schemaNode = this.objectMapper.valueToTree(schema);
-
-		// Handle case where ObjectMapper might return null (e.g., in mocked scenarios)
-		if (schemaNode == null) {
-			throw new JsonProcessingException("Failed to convert schema to JsonNode") {
-			};
-		}
-
-		return this.schemaFactory.getSchema(schemaNode);
-	}
-
-	/**
-	 * Generates a cache key for the given schema map.
-	 * @param schema the schema map
-	 * @return a cache key string
-	 */
-	protected String generateCacheKey(Map<String, Object> schema) {
-		if (schema.containsKey("$id")) {
-			// Use the (optional) "$id" field as the cache key if present
-			return "" + schema.get("$id");
-		}
-		// Fall back to schema's hash code as a simple cache key
-		// For more sophisticated caching, could use content-based hashing
-		return String.valueOf(schema.hashCode());
-	}
-
-	/**
-	 * Clears the schema cache. Useful for testing or memory management.
-	 */
-	public void clearCache() {
-		this.schemaCache.clear();
-	}
-
-	/**
-	 * Returns the current size of the schema cache.
-	 * @return the number of cached schemas
-	 */
-	public int getCacheSize() {
-		return this.schemaCache.size();
-	}
-
-}
diff --git a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/JacksonJsonSchemaValidatorSupplier.java b/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/JacksonJsonSchemaValidatorSupplier.java
deleted file mode 100644
index ae16d66e9..000000000
--- a/mcp-json-jackson2/src/main/java/io/modelcontextprotocol/json/schema/jackson/JacksonJsonSchemaValidatorSupplier.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2025 - 2025 the original author or authors.
- */
-
-package io.modelcontextprotocol.json.schema.jackson;
-
-import io.modelcontextprotocol.json.schema.JsonSchemaValidator;
-import io.modelcontextprotocol.json.schema.JsonSchemaValidatorSupplier;
-
-/**
- * A concrete implementation of {@link JsonSchemaValidatorSupplier} that provides a
- * {@link JsonSchemaValidator} instance based on the Jackson library.
- *
- * @see JsonSchemaValidatorSupplier
- * @see JsonSchemaValidator
- * @deprecated since 18.0.0, use
- * {@link io.modelcontextprotocol.json.schema.jackson2.JacksonJsonSchemaValidatorSupplier}
- * instead. Will be removed in 19.0.0.
- */
-public class JacksonJsonSchemaValidatorSupplier implements JsonSchemaValidatorSupplier {
-
-	/**
-	 * Returns a new instance of {@link JsonSchemaValidator} that uses the Jackson library
-	 * for JSON schema validation.
-	 * @return A {@link JsonSchemaValidator} instance.
-	 */
-	@Override
-	public JsonSchemaValidator get() {
-		return new DefaultJsonSchemaValidator();
-	}
-
-}
diff --git a/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson/DefaultJsonSchemaValidatorTests.java b/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson/DefaultJsonSchemaValidatorTests.java
deleted file mode 100644
index 66cba09b8..000000000
--- a/mcp-json-jackson2/src/test/java/io/modelcontextprotocol/json/jackson/DefaultJsonSchemaValidatorTests.java
+++ /dev/null
@@ -1,809 +0,0 @@
-/*
- * Copyright 2024-2024 the original author or authors.
- */
-
-package io.modelcontextprotocol.json.jackson;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertNull;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.when;
-
-import java.util.List;
-import java.util.Map;
-import java.util.stream.Stream;
-
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.MethodSource;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
-
-import com.fasterxml.jackson.core.type.TypeReference;
-import com.fasterxml.jackson.databind.ObjectMapper;
-
-import io.modelcontextprotocol.json.schema.JsonSchemaValidator.ValidationResponse;
-import io.modelcontextprotocol.json.schema.jackson.DefaultJsonSchemaValidator;
-
-/**
- * Tests for {@link DefaultJsonSchemaValidator}.
- *
- * @author Christian Tzolov
- */
-@Deprecated(forRemoval = true)
-class DefaultJsonSchemaValidatorTests {
-
-	private DefaultJsonSchemaValidator validator;
-
-	private ObjectMapper objectMapper;
-
-	@Mock
-	private ObjectMapper mockObjectMapper;
-
-	@BeforeEach
-	void setUp() {
-		MockitoAnnotations.openMocks(this);
-		validator = new DefaultJsonSchemaValidator();
-		objectMapper = new ObjectMapper();
-	}
-
-	/**
-	 * Utility method to convert JSON string to Map<String, Object>
-	 */
-	private Map<String, Object> toMap(String json) {
-		try {
-			return objectMapper.readValue(json, new TypeReference<Map<String, Object>>() {
-			});
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to parse JSON: " + json, e);
-		}
-	}
-
-	private List<Map<String, Object>> toListMap(String json) {
-		try {
-			return objectMapper.readValue(json, new TypeReference<List<Map<String, Object>>>() {
-			});
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to parse JSON: " + json, e);
-		}
-	}
-
-	@Test
-	void testDefaultConstructor() {
-		DefaultJsonSchemaValidator defaultValidator = new DefaultJsonSchemaValidator();
-
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"test": {"type": "string"}
-					}
-				}
-				""";
-		String contentJson = """
-				{
-					"test": "value"
-				}
-				""";
-
-		ValidationResponse response = defaultValidator.validate(toMap(schemaJson), toMap(contentJson));
-		assertTrue(response.valid());
-	}
-
-	@Test
-	void testConstructorWithObjectMapper() {
-		ObjectMapper customMapper = new ObjectMapper();
-		DefaultJsonSchemaValidator customValidator = new DefaultJsonSchemaValidator(customMapper);
-
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"test": {"type": "string"}
-					}
-				}
-				""";
-		String contentJson = """
-				{
-					"test": "value"
-				}
-				""";
-
-		ValidationResponse response = customValidator.validate(toMap(schemaJson), toMap(contentJson));
-		assertTrue(response.valid());
-	}
-
-	@Test
-	void testValidateWithValidStringSchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"},
-						"age": {"type": "integer"}
-					},
-					"required": ["name", "age"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"age": 30
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-		assertNotNull(response.jsonStructuredOutput());
-	}
-
-	@Test
-	void testValidateWithValidNumberSchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"price": {"type": "number", "minimum": 0},
-						"quantity": {"type": "integer", "minimum": 1}
-					},
-					"required": ["price", "quantity"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"price": 19.99,
-					"quantity": 5
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithValidArraySchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"items": {
-							"type": "array",
-							"items": {"type": "string"}
-						}
-					},
-					"required": ["items"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"items": ["apple", "banana", "cherry"]
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithValidArraySchemaTopLevelArray() {
-		String schemaJson = """
-				{
-					"$schema" : "https://json-schema.org/draft/2020-12/schema",
-					"type" : "array",
-					"items" : {
-						"type" : "object",
-						"properties" : {
-						"city" : {
-							"type" : "string"
-						},
-						"summary" : {
-							"type" : "string"
-						},
-						"temperatureC" : {
-							"type" : "number",
-							"format" : "float"
-						}
-						},
-						"required" : [ "city", "summary", "temperatureC" ]
-					},
-					"additionalProperties" : false
-				}
-					""";
-
-		String contentJson = """
-				[
-					{
-						"city": "London",
-						"summary": "Generally mild with frequent rainfall. Winters are cool and damp, summers are warm but rarely hot. Cloudy conditions are common throughout the year.",
-						"temperatureC": 11.3
-					},
-					{
-						"city": "New York",
-						"summary": "Four distinct seasons with hot and humid summers, cold winters with snow, and mild springs and autumns. Precipitation is fairly evenly distributed throughout the year.",
-						"temperatureC": 12.8
-					},
-					{
-						"city": "San Francisco",
-						"summary": "Mild year-round with a distinctive Mediterranean climate. Famous for summer fog, mild winters, and little temperature variation throughout the year. Very little rainfall in summer months.",
-						"temperatureC": 14.6
-					},
-					{
-						"city": "Tokyo",
-						"summary": "Humid subtropical climate with hot, wet summers and mild winters. Experiences a rainy season in early summer and occasional typhoons in late summer to early autumn.",
-						"temperatureC": 15.4
-					}
-				]
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-
-		// Validate as JSON string
-		ValidationResponse response = validator.validate(schema, contentJson);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-
-		List<Map<String, Object>> structuredContent = toListMap(contentJson);
-
-		// Validate as List<Map<String, Object>>
-		response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithInvalidTypeSchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"},
-						"age": {"type": "integer"}
-					},
-					"required": ["name", "age"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"age": "thirty"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-		assertTrue(response.errorMessage().contains("structuredContent does not match tool outputSchema"));
-	}
-
-	@Test
-	void testValidateWithMissingRequiredField() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"},
-						"age": {"type": "integer"}
-					},
-					"required": ["name", "age"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-	}
-
-	@Test
-	void testValidateWithAdditionalPropertiesNotAllowed() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"}
-					},
-					"required": ["name"],
-					"additionalProperties": false
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"extraField": "should not be allowed"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-	}
-
-	@Test
-	void testValidateWithAdditionalPropertiesExplicitlyAllowed() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"}
-					},
-					"required": ["name"],
-					"additionalProperties": true
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"extraField": "should be allowed"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithDefaultAdditionalProperties() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"}
-					},
-					"required": ["name"],
-					"additionalProperties": true
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"extraField": "should be allowed"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithAdditionalPropertiesExplicitlyDisallowed() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"name": {"type": "string"}
-					},
-					"required": ["name"],
-					"additionalProperties": false
-				}
-				""";
-
-		String contentJson = """
-				{
-					"name": "John Doe",
-					"extraField": "should not be allowed"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-	}
-
-	@Test
-	void testValidateWithEmptySchema() {
-		String schemaJson = """
-				{
-					"additionalProperties": true
-				}
-				""";
-
-		String contentJson = """
-				{
-					"anything": "goes"
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithEmptyContent() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {}
-				}
-				""";
-
-		String contentJson = """
-				{}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithNestedObjectSchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"person": {
-							"type": "object",
-							"properties": {
-								"name": {"type": "string"},
-								"address": {
-									"type": "object",
-									"properties": {
-										"street": {"type": "string"},
-										"city": {"type": "string"}
-									},
-									"required": ["street", "city"]
-								}
-							},
-							"required": ["name", "address"]
-						}
-					},
-					"required": ["person"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"person": {
-						"name": "John Doe",
-						"address": {
-							"street": "123 Main St",
-							"city": "Anytown"
-						}
-					}
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-	}
-
-	@Test
-	void testValidateWithInvalidNestedObjectSchema() {
-		String schemaJson = """
-				{
-					"type": "object",
-					"properties": {
-						"person": {
-							"type": "object",
-							"properties": {
-								"name": {"type": "string"},
-								"address": {
-									"type": "object",
-									"properties": {
-										"street": {"type": "string"},
-										"city": {"type": "string"}
-									},
-									"required": ["street", "city"]
-								}
-							},
-							"required": ["name", "address"]
-						}
-					},
-					"required": ["person"]
-				}
-				""";
-
-		String contentJson = """
-				{
-					"person": {
-						"name": "John Doe",
-						"address": {
-							"street": "123 Main St"
-						}
-					}
-				}
-				""";
-
-		Map<String, Object> schema = toMap(schemaJson);
-		Map<String, Object> structuredContent = toMap(contentJson);
-
-		ValidationResponse response = validator.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-	}
-
-	@Test
-	void testValidateWithJsonProcessingException() throws Exception {
-		DefaultJsonSchemaValidator validatorWithMockMapper = new DefaultJsonSchemaValidator(mockObjectMapper);
-
-		Map<String, Object> schema = Map.of("type", "object");
-		Map<String, Object> structuredContent = Map.of("key", "value");
-
-		// This will trigger our null check and throw JsonProcessingException
-		when(mockObjectMapper.valueToTree(any())).thenReturn(null);
-
-		ValidationResponse response = validatorWithMockMapper.validate(schema, structuredContent);
-
-		assertFalse(response.valid());
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Error parsing tool JSON Schema"));
-		assertTrue(response.errorMessage().contains("Failed to convert schema to JsonNode"));
-	}
-
-	@ParameterizedTest
-	@MethodSource("provideValidSchemaAndContentPairs")
-	void testValidateWithVariousValidInputs(Map<String, Object> schema, Map<String, Object> content) {
-		ValidationResponse response = validator.validate(schema, content);
-
-		assertTrue(response.valid(), "Expected validation to pass for schema: " + schema + " and content: " + content);
-		assertNull(response.errorMessage());
-	}
-
-	@ParameterizedTest
-	@MethodSource("provideInvalidSchemaAndContentPairs")
-	void testValidateWithVariousInvalidInputs(Map<String, Object> schema, Map<String, Object> content) {
-		ValidationResponse response = validator.validate(schema, content);
-
-		assertFalse(response.valid(), "Expected validation to fail for schema: " + schema + " and content: " + content);
-		assertNotNull(response.errorMessage());
-		assertTrue(response.errorMessage().contains("Validation failed"));
-	}
-
-	private static Map<String, Object> staticToMap(String json) {
-		try {
-			ObjectMapper mapper = new ObjectMapper();
-			return mapper.readValue(json, new TypeReference<Map<String, Object>>() {
-			});
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to parse JSON: " + json, e);
-		}
-	}
-
-	private static Stream<Arguments> provideValidSchemaAndContentPairs() {
-		return Stream.of(
-				// Boolean schema
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"flag": {"type": "boolean"}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"flag": true
-						}
-						""")),
-				// String with additional properties allowed
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"name": {"type": "string"}
-							},
-							"additionalProperties": true
-						}
-						"""), staticToMap("""
-						{
-							"name": "test",
-							"extra": "allowed"
-						}
-						""")),
-				// Array with specific items
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"numbers": {
-									"type": "array",
-									"items": {"type": "number"}
-								}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"numbers": [1.0, 2.5, 3.14]
-						}
-						""")),
-				// Enum validation
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"status": {
-									"type": "string",
-									"enum": ["active", "inactive", "pending"]
-								}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"status": "active"
-						}
-						""")));
-	}
-
-	private static Stream<Arguments> provideInvalidSchemaAndContentPairs() {
-		return Stream.of(
-				// Wrong boolean type
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"flag": {"type": "boolean"}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"flag": "true"
-						}
-						""")),
-				// Array with wrong item types
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"numbers": {
-									"type": "array",
-									"items": {"type": "number"}
-								}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"numbers": ["one", "two", "three"]
-						}
-						""")),
-				// Invalid enum value
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"status": {
-									"type": "string",
-									"enum": ["active", "inactive", "pending"]
-								}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"status": "unknown"
-						}
-						""")),
-				// Minimum constraint violation
-				Arguments.of(staticToMap("""
-						{
-							"type": "object",
-							"properties": {
-								"age": {"type": "integer", "minimum": 0}
-							}
-						}
-						"""), staticToMap("""
-						{
-							"age": -5
-						}
-						""")));
-	}
-
-	@Test
-	void testValidationResponseToValid() {
-		String jsonOutput = "{\"test\":\"value\"}";
-		ValidationResponse response = ValidationResponse.asValid(jsonOutput);
-		assertTrue(response.valid());
-		assertNull(response.errorMessage());
-		assertEquals(jsonOutput, response.jsonStructuredOutput());
-	}
-
-	@Test
-	void testValidationResponseToInvalid() {
-		String errorMessage = "Test error message";
-		ValidationResponse response = ValidationResponse.asInvalid(errorMessage);
-		assertFalse(response.valid());
-		assertEquals(errorMessage, response.errorMessage());
-		assertNull(response.jsonStructuredOutput());
-	}
-
-	@Test
-	void testValidationResponseRecord() {
-		ValidationResponse response1 = new ValidationResponse(true, null, "{\"valid\":true}");
-		ValidationResponse response2 = new ValidationResponse(false, "Error", null);
-
-		assertTrue(response1.valid());
-		assertNull(response1.errorMessage());
-		assertEquals("{\"valid\":true}", response1.jsonStructuredOutput());
-
-		assertFalse(response2.valid());
-		assertEquals("Error", response2.errorMessage());
-		assertNull(response2.jsonStructuredOutput());
-
-		// Test equality
-		ValidationResponse response3 = new ValidationResponse(true, null, "{\"valid\":true}");
-		assertEquals(response1, response3);
-		assertNotEquals(response1, response2);
-	}
-
-}
diff --git a/mcp-test/src/main/java/io/modelcontextprotocol/AbstractStatelessIntegrationTests.java b/mcp-test/src/main/java/io/modelcontextprotocol/AbstractStatelessIntegrationTests.java
index 240732ebe..7755ce456 100644
--- a/mcp-test/src/main/java/io/modelcontextprotocol/AbstractStatelessIntegrationTests.java
+++ b/mcp-test/src/main/java/io/modelcontextprotocol/AbstractStatelessIntegrationTests.java
@@ -82,7 +82,10 @@ void testToolCallSuccess(String clientType) {
 
 		var clientBuilder = clientBuilders.get(clientType);
 
-		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
+		var callResponse = McpSchema.CallToolResult.builder()
+			.content(List.of(new McpSchema.TextContent("CALL RESPONSE")))
+			.isError(false)
+			.build();
 		McpStatelessServerFeatures.SyncToolSpecification tool1 = McpStatelessServerFeatures.SyncToolSpecification
 			.builder()
 			.tool(Tool.builder().name("tool1").description("tool1 description").inputSchema(EMPTY_JSON_SCHEMA).build())
@@ -170,7 +173,10 @@ void testToolListChangeHandlingSuccess(String clientType) {
 
 		var clientBuilder = clientBuilders.get(clientType);
 
-		var callResponse = new McpSchema.CallToolResult(List.of(new McpSchema.TextContent("CALL RESPONSE")), null);
+		var callResponse = McpSchema.CallToolResult.builder()
+			.content(List.of(new McpSchema.TextContent("CALL RESPONSE")))
+			.isError(false)
+			.build();
 		McpStatelessServerFeatures.SyncToolSpecification tool1 = McpStatelessServerFeatures.SyncToolSpecification
 			.builder()
 			.tool(Tool.builder().name("tool1").description("tool1 description").inputSchema(EMPTY_JSON_SCHEMA).build())
diff --git a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
index d6677ec9a..9cd1191d1 100644
--- a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
+++ b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpAsyncServerTests.java
@@ -95,26 +95,6 @@ void testImmediateClose() {
 	// ---------------------------------------
 	// Tools Tests
 	// ---------------------------------------
-	@Test
-	@Deprecated
-	void testAddTool() {
-		Tool newTool = McpSchema.Tool.builder()
-			.name("new-tool")
-			.title("New test tool")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-		var mcpAsyncServer = prepareAsyncServerBuilder().serverInfo("test-server", "1.0.0")
-			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.build();
-
-		StepVerifier
-			.create(mcpAsyncServer.addTool(new McpServerFeatures.AsyncToolSpecification(newTool,
-					(exchange, args) -> Mono.just(CallToolResult.builder().content(List.of()).isError(false).build()))))
-			.verifyComplete();
-
-		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
-	}
-
 	@Test
 	void testAddToolCall() {
 		Tool newTool = McpSchema.Tool.builder()
@@ -136,29 +116,6 @@ void testAddToolCall() {
 		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
 	}
 
-	@Test
-	@Deprecated
-	void testAddDuplicateTool() {
-		Tool duplicateTool = McpSchema.Tool.builder()
-			.name(TEST_TOOL_NAME)
-			.title("Duplicate tool")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-
-		var mcpAsyncServer = prepareAsyncServerBuilder().serverInfo("test-server", "1.0.0")
-			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(duplicateTool,
-					(exchange, args) -> Mono.just(CallToolResult.builder().content(List.of()).isError(false).build()))
-			.build();
-
-		StepVerifier
-			.create(mcpAsyncServer.addTool(new McpServerFeatures.AsyncToolSpecification(duplicateTool,
-					(exchange, args) -> Mono.just(CallToolResult.builder().content(List.of()).isError(false).build()))))
-			.verifyComplete();
-
-		assertThatCode(() -> mcpAsyncServer.closeGracefully().block(Duration.ofSeconds(10))).doesNotThrowAnyException();
-	}
-
 	@Test
 	void testAddDuplicateToolCall() {
 		Tool duplicateTool = McpSchema.Tool.builder()
diff --git a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
index 0a59d0aae..eee5f1a4d 100644
--- a/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
+++ b/mcp-test/src/main/java/io/modelcontextprotocol/server/AbstractMcpSyncServerTests.java
@@ -99,25 +99,6 @@ void testGetAsyncServer() {
 	// Tools Tests
 	// ---------------------------------------
 
-	@Test
-	@Deprecated
-	void testAddTool() {
-		var mcpSyncServer = prepareSyncServerBuilder().serverInfo("test-server", "1.0.0")
-			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.build();
-
-		Tool newTool = McpSchema.Tool.builder()
-			.name("new-tool")
-			.title("New test tool")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-		assertThatCode(() -> mcpSyncServer.addTool(new McpServerFeatures.SyncToolSpecification(newTool,
-				(exchange, args) -> CallToolResult.builder().content(List.of()).isError(false).build())))
-			.doesNotThrowAnyException();
-
-		assertThatCode(mcpSyncServer::closeGracefully).doesNotThrowAnyException();
-	}
-
 	@Test
 	void testAddToolCall() {
 		var mcpSyncServer = prepareSyncServerBuilder().serverInfo("test-server", "1.0.0")
@@ -138,27 +119,6 @@ void testAddToolCall() {
 		assertThatCode(mcpSyncServer::closeGracefully).doesNotThrowAnyException();
 	}
 
-	@Test
-	@Deprecated
-	void testAddDuplicateTool() {
-		Tool duplicateTool = McpSchema.Tool.builder()
-			.name(TEST_TOOL_NAME)
-			.title("Duplicate tool")
-			.inputSchema(EMPTY_JSON_SCHEMA)
-			.build();
-
-		var mcpSyncServer = prepareSyncServerBuilder().serverInfo("test-server", "1.0.0")
-			.capabilities(ServerCapabilities.builder().tools(true).build())
-			.tool(duplicateTool, (exchange, args) -> CallToolResult.builder().content(List.of()).isError(false).build())
-			.build();
-
-		assertThatCode(() -> mcpSyncServer.addTool(new McpServerFeatures.SyncToolSpecification(duplicateTool,
-				(exchange, args) -> CallToolResult.builder().content(List.of()).isError(false).build())))
-			.doesNotThrowAnyException();
-
-		assertThatCode(mcpSyncServer::closeGracefully).doesNotThrowAnyException();
-	}
-
 	@Test
 	void testAddDuplicateToolCall() {
 		Tool duplicateTool = McpSchema.Tool.builder()
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java b/mcp-test/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
index f93e760f1..4e74dac3e 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/MockMcpClientTransport.java
@@ -13,6 +13,7 @@
 import io.modelcontextprotocol.json.TypeRef;
 import io.modelcontextprotocol.spec.McpClientTransport;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import io.modelcontextprotocol.spec.McpSchema.JSONRPCNotification;
 import io.modelcontextprotocol.spec.McpSchema.JSONRPCRequest;
 import reactor.core.publisher.Mono;
@@ -29,7 +30,7 @@ public class MockMcpClientTransport implements McpClientTransport {
 
 	private final BiConsumer<MockMcpClientTransport, McpSchema.JSONRPCMessage> interceptor;
 
-	private String protocolVersion = McpSchema.LATEST_PROTOCOL_VERSION;
+	private String protocolVersion = ProtocolVersions.MCP_2025_11_25;
 
 	public MockMcpClientTransport() {
 		this((t, msg) -> {
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/client/McpAsyncClientResponseHandlerTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/client/McpAsyncClientResponseHandlerTests.java
index 612a65898..47a229afd 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/client/McpAsyncClientResponseHandlerTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/client/McpAsyncClientResponseHandlerTests.java
@@ -13,6 +13,7 @@
 import io.modelcontextprotocol.json.TypeRef;
 import io.modelcontextprotocol.MockMcpClientTransport;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
 import io.modelcontextprotocol.spec.McpSchema.PaginatedRequest;
@@ -42,7 +43,7 @@ private static MockMcpClientTransport initializationEnabledTransport() {
 
 	private static MockMcpClientTransport initializationEnabledTransport(
 			McpSchema.ServerCapabilities mockServerCapabilities, McpSchema.Implementation mockServerInfo) {
-		McpSchema.InitializeResult mockInitResult = new McpSchema.InitializeResult(McpSchema.LATEST_PROTOCOL_VERSION,
+		McpSchema.InitializeResult mockInitResult = new McpSchema.InitializeResult(ProtocolVersions.MCP_2025_11_25,
 				mockServerCapabilities, mockServerInfo, "Test instructions");
 
 		return new MockMcpClientTransport((t, message) -> {
@@ -51,7 +52,7 @@ private static MockMcpClientTransport initializationEnabledTransport(
 						r.id(), mockInitResult, null);
 				t.simulateIncomingMessage(initResponse);
 			}
-		}).withProtocolVersion(McpSchema.LATEST_PROTOCOL_VERSION);
+		}).withProtocolVersion(ProtocolVersions.MCP_2025_11_25);
 	}
 
 	@Test
@@ -212,8 +213,12 @@ void testResourcesChangeNotificationHandling() {
 		assertThat(asyncMcpClient.initialize().block()).isNotNull();
 
 		// Create a mock resources list that the server will return
-		McpSchema.Resource mockResource = new McpSchema.Resource("test://resource", "Test Resource", "A test resource",
-				"text/plain", null);
+		McpSchema.Resource mockResource = McpSchema.Resource.builder()
+			.uri("test://resource")
+			.name("Test Resource")
+			.description("A test resource")
+			.mimeType("text/plain")
+			.build();
 		McpSchema.ListResourcesResult mockResourcesResult = new McpSchema.ListResourcesResult(List.of(mockResource),
 				null);
 
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/client/McpClientProtocolVersionTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/client/McpClientProtocolVersionTests.java
index a94b9b6a7..03f64aa64 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/client/McpClientProtocolVersionTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/client/McpClientProtocolVersionTests.java
@@ -11,6 +11,7 @@
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
@@ -68,7 +69,7 @@ void shouldNegotiateSpecificVersion() {
 			.requestTimeout(REQUEST_TIMEOUT)
 			.build();
 
-		client.setProtocolVersions(List.of(oldVersion, McpSchema.LATEST_PROTOCOL_VERSION));
+		client.setProtocolVersions(List.of(oldVersion, ProtocolVersions.MCP_2025_11_25));
 
 		try {
 			Mono<InitializeResult> initializeResultMono = client.initialize();
@@ -77,7 +78,7 @@ void shouldNegotiateSpecificVersion() {
 				McpSchema.JSONRPCRequest request = transport.getLastSentMessageAsRequest();
 				assertThat(request.params()).isInstanceOf(McpSchema.InitializeRequest.class);
 				McpSchema.InitializeRequest initRequest = (McpSchema.InitializeRequest) request.params();
-				assertThat(initRequest.protocolVersion()).isIn(List.of(oldVersion, McpSchema.LATEST_PROTOCOL_VERSION));
+				assertThat(initRequest.protocolVersion()).isIn(List.of(oldVersion, ProtocolVersions.MCP_2025_11_25));
 
 				transport.simulateIncomingMessage(new McpSchema.JSONRPCResponse(McpSchema.JSONRPC_VERSION, request.id(),
 						new McpSchema.InitializeResult(oldVersion, ServerCapabilities.builder().build(),
@@ -123,7 +124,7 @@ void shouldFailForUnsupportedVersion() {
 	void shouldUseHighestVersionWhenMultipleSupported() {
 		String oldVersion = "0.1.0";
 		String middleVersion = "0.2.0";
-		String latestVersion = McpSchema.LATEST_PROTOCOL_VERSION;
+		String latestVersion = ProtocolVersions.MCP_2025_11_25;
 
 		MockMcpClientTransport transport = new MockMcpClientTransport();
 		McpAsyncClient client = McpClient.async(transport)
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportTest.java b/mcp-test/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportTest.java
index 8ddd54266..f88736a5d 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportTest.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransportTest.java
@@ -8,6 +8,7 @@
 import io.modelcontextprotocol.client.transport.customizer.McpSyncHttpClientRequestCustomizer;
 import io.modelcontextprotocol.common.McpTransportContext;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Map;
@@ -78,7 +79,7 @@ void testRequestCustomizer() throws URISyntaxException {
 
 		withTransport(transport, (t) -> {
 			// Send test message
-			var initializeRequest = new McpSchema.InitializeRequest(McpSchema.LATEST_PROTOCOL_VERSION,
+			var initializeRequest = new McpSchema.InitializeRequest(ProtocolVersions.MCP_2025_11_25,
 					McpSchema.ClientCapabilities.builder().roots(true).build(),
 					new McpSchema.Implementation("MCP Client", "0.3.1"));
 			var testMessage = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION, McpSchema.METHOD_INITIALIZE,
@@ -108,7 +109,7 @@ void testAsyncRequestCustomizer() throws URISyntaxException {
 
 		withTransport(transport, (t) -> {
 			// Send test message
-			var initializeRequest = new McpSchema.InitializeRequest(McpSchema.LATEST_PROTOCOL_VERSION,
+			var initializeRequest = new McpSchema.InitializeRequest(ProtocolVersions.MCP_2025_11_25,
 					McpSchema.ClientCapabilities.builder().roots(true).build(),
 					new McpSchema.Implementation("MCP Client", "0.3.1"));
 			var testMessage = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION, McpSchema.METHOD_INITIALIZE,
@@ -131,7 +132,7 @@ void testCloseUninitialized() {
 
 		StepVerifier.create(transport.closeGracefully()).verifyComplete();
 
-		var initializeRequest = new McpSchema.InitializeRequest(McpSchema.LATEST_PROTOCOL_VERSION,
+		var initializeRequest = new McpSchema.InitializeRequest(ProtocolVersions.MCP_2025_11_25,
 				McpSchema.ClientCapabilities.builder().roots(true).build(),
 				new McpSchema.Implementation("MCP Client", "0.3.1"));
 		var testMessage = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION, McpSchema.METHOD_INITIALIZE,
@@ -146,7 +147,7 @@ void testCloseUninitialized() {
 	void testCloseInitialized() {
 		var transport = HttpClientStreamableHttpTransport.builder(host).build();
 
-		var initializeRequest = new McpSchema.InitializeRequest(McpSchema.LATEST_PROTOCOL_VERSION,
+		var initializeRequest = new McpSchema.InitializeRequest(ProtocolVersions.MCP_2025_11_25,
 				McpSchema.ClientCapabilities.builder().roots(true).build(),
 				new McpSchema.Implementation("MCP Client", "0.3.1"));
 		var testMessage = new McpSchema.JSONRPCRequest(McpSchema.JSONRPC_VERSION, McpSchema.METHOD_INITIALIZE,
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/common/AsyncServerMcpTransportContextIntegrationTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/common/AsyncServerMcpTransportContextIntegrationTests.java
index 8b2dea462..ce381436d 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/common/AsyncServerMcpTransportContextIntegrationTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/common/AsyncServerMcpTransportContextIntegrationTests.java
@@ -132,8 +132,10 @@ public class AsyncServerMcpTransportContextIntegrationTests {
 
 	private final BiFunction<McpTransportContext, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> asyncStatelessHandler = (
 			transportContext, request) -> {
-		return Mono
-			.just(new McpSchema.CallToolResult(transportContext.get("server-side-header-value").toString(), null));
+		return Mono.just(McpSchema.CallToolResult.builder()
+			.addTextContent(transportContext.get("server-side-header-value").toString())
+			.isError(false)
+			.build());
 	};
 
 	private final BiFunction<McpAsyncServerExchange, McpSchema.CallToolRequest, Mono<McpSchema.CallToolResult>> asyncStatefulHandler = (
@@ -198,7 +200,10 @@ void asyncClientStreamableServer() {
 
 		var mcpServer = McpServer.async(streamableServerTransport)
 			.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
-			.tools(new McpServerFeatures.AsyncToolSpecification(tool, null, asyncStatefulHandler))
+			.tools(McpServerFeatures.AsyncToolSpecification.builder()
+				.tool(tool)
+				.callHandler(asyncStatefulHandler)
+				.build())
 			.build();
 
 		StepVerifier.create(asyncStreamableClient.initialize()).assertNext(initResult -> {
@@ -229,7 +234,10 @@ void asyncClientSseServer() {
 
 		var mcpServer = McpServer.async(sseServerTransport)
 			.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
-			.tools(new McpServerFeatures.AsyncToolSpecification(tool, null, asyncStatefulHandler))
+			.tools(McpServerFeatures.AsyncToolSpecification.builder()
+				.tool(tool)
+				.callHandler(asyncStatefulHandler)
+				.build())
 			.build();
 
 		StepVerifier.create(asyncSseClient.initialize()).assertNext(initResult -> {
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/common/HttpClientStreamableHttpVersionNegotiationIntegrationTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/common/HttpClientStreamableHttpVersionNegotiationIntegrationTests.java
index 614172b84..29eef1410 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/common/HttpClientStreamableHttpVersionNegotiationIntegrationTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/common/HttpClientStreamableHttpVersionNegotiationIntegrationTests.java
@@ -47,12 +47,14 @@ class HttpClientStreamableHttpVersionNegotiationIntegrationTests {
 		.build();
 
 	private final BiFunction<McpSyncServerExchange, McpSchema.CallToolRequest, McpSchema.CallToolResult> toolHandler = (
-			exchange, request) -> new McpSchema.CallToolResult(
-					exchange.transportContext().get("protocol-version").toString(), null);
+			exchange, request) -> McpSchema.CallToolResult.builder()
+				.addTextContent(exchange.transportContext().get("protocol-version").toString())
+				.isError(false)
+				.build();
 
 	McpSyncServer mcpServer = McpServer.sync(transport)
 		.capabilities(McpSchema.ServerCapabilities.builder().tools(false).build())
-		.tools(new McpServerFeatures.SyncToolSpecification(toolSpec, null, toolHandler))
+		.tools(McpServerFeatures.SyncToolSpecification.builder().tool(toolSpec).callHandler(toolHandler).build())
 		.build();
 
 	@AfterEach
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/common/SyncServerMcpTransportContextIntegrationTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/common/SyncServerMcpTransportContextIntegrationTests.java
index cc8f4c4be..563e2167d 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/common/SyncServerMcpTransportContextIntegrationTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/common/SyncServerMcpTransportContextIntegrationTests.java
@@ -78,8 +78,10 @@ public class SyncServerMcpTransportContextIntegrationTests {
 	};
 
 	private final BiFunction<McpTransportContext, McpSchema.CallToolRequest, McpSchema.CallToolResult> statelessHandler = (
-			transportContext,
-			request) -> new McpSchema.CallToolResult(transportContext.get("server-side-header-value").toString(), null);
+			transportContext, request) -> McpSchema.CallToolResult.builder()
+				.addTextContent(transportContext.get("server-side-header-value").toString())
+				.isError(false)
+				.build();
 
 	private final BiFunction<McpSyncServerExchange, McpSchema.CallToolRequest, McpSchema.CallToolResult> statefulHandler = (
 			exchange, request) -> statelessHandler.apply(exchange.transportContext(), request);
@@ -172,7 +174,7 @@ void streamableServer() {
 
 		var mcpServer = McpServer.sync(streamableServerTransport)
 			.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
-			.tools(new McpServerFeatures.SyncToolSpecification(tool, null, statefulHandler))
+			.tools(McpServerFeatures.SyncToolSpecification.builder().tool(tool).callHandler(statefulHandler).build())
 			.build();
 
 		McpSchema.InitializeResult initResult = streamableClient.initialize();
@@ -198,7 +200,7 @@ void sseServer() {
 
 		var mcpServer = McpServer.sync(sseServerTransport)
 			.capabilities(McpSchema.ServerCapabilities.builder().tools(true).build())
-			.tools(new McpServerFeatures.SyncToolSpecification(tool, null, statefulHandler))
+			.tools(McpServerFeatures.SyncToolSpecification.builder().tool(tool).callHandler(statefulHandler).build())
 			.build();
 
 		McpSchema.InitializeResult initResult = sseClient.initialize();
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/server/McpServerProtocolVersionTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/server/McpServerProtocolVersionTests.java
index cdd2bacb7..d9f899020 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/server/McpServerProtocolVersionTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/server/McpServerProtocolVersionTests.java
@@ -10,6 +10,7 @@
 import io.modelcontextprotocol.MockMcpServerTransport;
 import io.modelcontextprotocol.MockMcpServerTransportProvider;
 import io.modelcontextprotocol.spec.McpSchema;
+import io.modelcontextprotocol.spec.ProtocolVersions;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -36,8 +37,7 @@ void shouldUseLatestVersionByDefault() {
 
 		String requestId = UUID.randomUUID().toString();
 
-		transportProvider
-			.simulateIncomingMessage(jsonRpcInitializeRequest(requestId, McpSchema.LATEST_PROTOCOL_VERSION));
+		transportProvider.simulateIncomingMessage(jsonRpcInitializeRequest(requestId, ProtocolVersions.MCP_2025_11_25));
 
 		McpSchema.JSONRPCMessage response = serverTransport.getLastSentMessage();
 		assertThat(response).isInstanceOf(McpSchema.JSONRPCResponse.class);
@@ -60,7 +60,7 @@ void shouldNegotiateSpecificVersion() {
 
 		McpAsyncServer server = McpServer.async(transportProvider).serverInfo(SERVER_INFO).build();
 
-		server.setProtocolVersions(List.of(oldVersion, McpSchema.LATEST_PROTOCOL_VERSION));
+		server.setProtocolVersions(List.of(oldVersion, ProtocolVersions.MCP_2025_11_25));
 
 		String requestId = UUID.randomUUID().toString();
 
@@ -105,7 +105,7 @@ void shouldSuggestLatestVersionForUnsupportedVersion() {
 	void shouldUseHighestVersionWhenMultipleSupported() {
 		String oldVersion = "0.1.0";
 		String middleVersion = "0.2.0";
-		String latestVersion = McpSchema.LATEST_PROTOCOL_VERSION;
+		String latestVersion = ProtocolVersions.MCP_2025_11_25;
 
 		MockMcpServerTransport serverTransport = new MockMcpServerTransport();
 		var transportProvider = new MockMcpServerTransportProvider(serverTransport);
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/server/transport/StdioServerTransportProviderTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/server/transport/StdioServerTransportProviderTests.java
index 873d48e36..5390cc4c2 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/server/transport/StdioServerTransportProviderTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/server/transport/StdioServerTransportProviderTests.java
@@ -185,7 +185,7 @@ void shouldHandleNotificationBeforeSessionFactoryIsSet() {
 		// Send notification before setting session factory
 		StepVerifier.create(transportProvider.notifyClients("testNotification", Map.of("key", "value")))
 			.verifyErrorSatisfies(error -> {
-				assertThat(error).isInstanceOf(McpError.class);
+				assertThat(error).isInstanceOf(IllegalStateException.class);
 			});
 	}
 
diff --git a/mcp-test/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java b/mcp-test/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java
index c732b1cc1..942e0a6e2 100644
--- a/mcp-test/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java
+++ b/mcp-test/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java
@@ -17,10 +17,10 @@
 import java.util.List;
 import java.util.Map;
 
+import io.modelcontextprotocol.spec.McpSchema.TextResourceContents;
 import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
 
-import io.modelcontextprotocol.spec.McpSchema.TextResourceContents;
 import net.javacrumbs.jsonunit.core.Option;
 
 /**
@@ -72,7 +72,7 @@ void testContentDeserializationWrongType() {
 
 	@Test
 	void testImageContent() throws Exception {
-		McpSchema.ImageContent test = new McpSchema.ImageContent(null, null, "base64encodeddata", "image/png");
+		McpSchema.ImageContent test = new McpSchema.ImageContent(null, "base64encodeddata", "image/png");
 		String value = JSON_MAPPER.writeValueAsString(test);
 
 		assertThatJson(value).when(Option.IGNORING_ARRAY_ORDER)
@@ -160,7 +160,7 @@ void testEmbeddedResource() throws Exception {
 		McpSchema.TextResourceContents resourceContents = new McpSchema.TextResourceContents("resource://test",
 				"text/plain", "Sample resource content");
 
-		McpSchema.EmbeddedResource test = new McpSchema.EmbeddedResource(null, null, resourceContents);
+		McpSchema.EmbeddedResource test = new McpSchema.EmbeddedResource(null, resourceContents);
 
 		String value = JSON_MAPPER.writeValueAsString(test);
 		assertThatJson(value).when(Option.IGNORING_ARRAY_ORDER)
@@ -191,7 +191,7 @@ void testEmbeddedResourceWithBlobContents() throws Exception {
 		McpSchema.BlobResourceContents resourceContents = new McpSchema.BlobResourceContents("resource://test",
 				"application/octet-stream", "base64encodedblob");
 
-		McpSchema.EmbeddedResource test = new McpSchema.EmbeddedResource(null, null, resourceContents);
+		McpSchema.EmbeddedResource test = new McpSchema.EmbeddedResource(null, resourceContents);
 
 		String value = JSON_MAPPER.writeValueAsString(test);
 		assertThatJson(value).when(Option.IGNORING_ARRAY_ORDER)
@@ -366,8 +366,13 @@ void testResource() throws Exception {
 		McpSchema.Annotations annotations = new McpSchema.Annotations(
 				Arrays.asList(McpSchema.Role.USER, McpSchema.Role.ASSISTANT), 0.8);
 
-		McpSchema.Resource resource = new McpSchema.Resource("resource://test", "Test Resource", "A test resource",
-				"text/plain", annotations);
+		McpSchema.Resource resource = McpSchema.Resource.builder()
+			.uri("resource://test")
+			.name("Test Resource")
+			.description("A test resource")
+			.mimeType("text/plain")
+			.annotations(annotations)
+			.build();
 
 		String value = JSON_MAPPER.writeValueAsString(resource);
 		assertThatJson(value).when(Option.IGNORING_ARRAY_ORDER)
@@ -451,11 +456,19 @@ void testResourceTemplate() throws Exception {
 
 	@Test
 	void testListResourcesResult() throws Exception {
-		McpSchema.Resource resource1 = new McpSchema.Resource("resource://test1", "Test Resource 1",
-				"First test resource", "text/plain", null);
+		McpSchema.Resource resource1 = McpSchema.Resource.builder()
+			.uri("resource://test1")
+			.name("Test Resource 1")
+			.description("First test resource")
+			.mimeType("text/plain")
+			.build();
 
-		McpSchema.Resource resource2 = new McpSchema.Resource("resource://test2", "Test Resource 2",
-				"Second test resource", "application/json", null);
+		McpSchema.Resource resource2 = McpSchema.Resource.builder()
+			.uri("resource://test2")
+			.name("Test Resource 2")
+			.description("Second test resource")
+			.mimeType("application/json")
+			.build();
 
 		Map<String, Object> meta = Map.of("metaKey", "metaValue");
 
@@ -1274,7 +1287,7 @@ void testCallToolResultBuilder() throws Exception {
 	@Test
 	void testCallToolResultBuilderWithMultipleContents() throws Exception {
 		McpSchema.TextContent textContent = new McpSchema.TextContent("Text result");
-		McpSchema.ImageContent imageContent = new McpSchema.ImageContent(null, null, "base64data", "image/png");
+		McpSchema.ImageContent imageContent = new McpSchema.ImageContent(null, "base64data", "image/png");
 
 		McpSchema.CallToolResult result = McpSchema.CallToolResult.builder()
 			.addContent(textContent)
@@ -1295,7 +1308,7 @@ void testCallToolResultBuilderWithMultipleContents() throws Exception {
 	@Test
 	void testCallToolResultBuilderWithContentList() throws Exception {
 		McpSchema.TextContent textContent = new McpSchema.TextContent("Text result");
-		McpSchema.ImageContent imageContent = new McpSchema.ImageContent(null, null, "base64data", "image/png");
+		McpSchema.ImageContent imageContent = new McpSchema.ImageContent(null, "base64data", "image/png");
 		List<McpSchema.Content> contents = Arrays.asList(textContent, imageContent);
 
 		McpSchema.CallToolResult result = McpSchema.CallToolResult.builder().content(contents).isError(true).build();
@@ -1326,27 +1339,6 @@ void testCallToolResultBuilderWithErrorResult() throws Exception {
 					{"content":[{"type":"text","text":"Error: Operation failed"}],"isError":true}"""));
 	}
 
-	@Test
-	void testCallToolResultStringConstructor() throws Exception {
-		// Test the existing string constructor alongside the builder
-		McpSchema.CallToolResult result1 = new McpSchema.CallToolResult("Simple result", false);
-		McpSchema.CallToolResult result2 = McpSchema.CallToolResult.builder()
-			.addTextContent("Simple result")
-			.isError(false)
-			.build();
-
-		String value1 = JSON_MAPPER.writeValueAsString(result1);
-		String value2 = JSON_MAPPER.writeValueAsString(result2);
-
-		// Both should produce the same JSON
-		assertThat(value1).isEqualTo(value2);
-		assertThatJson(value1).when(Option.IGNORING_ARRAY_ORDER)
-			.when(Option.IGNORING_EXTRA_ARRAY_ITEMS)
-			.isObject()
-			.isEqualTo(json("""
-					{"content":[{"type":"text","text":"Simple result"}],"isError":false}"""));
-	}
-
 	// Sampling Tests
 
 	@Test