feat(mcp): Add builder for CreateMessageRequest (#60)

- Implements a builder pattern for CreateMessageRequest
- Updates corresponding tests to use the new builder syntax
- Add ModelPreferences builder and ModelHint helper
- Use builder pattern for CreateMessageRequest in integration tests

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/WebFluxSseIntegrationTests.java

@@ -24,6 +24,7 @@ import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageRequest;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageResult;
 import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+import io.modelcontextprotocol.spec.McpSchema.ModelPreferences;
 import io.modelcontextprotocol.spec.McpSchema.Role;
 import io.modelcontextprotocol.spec.McpSchema.Root;
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
@@ -45,6 +46,7 @@ import org.springframework.web.reactive.function.server.RouterFunctions;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.awaitility.Awaitility.await;
+import static org.junit.Assert.assertThat;
 import static org.mockito.Mockito.mock;
 
 public class WebFluxSseIntegrationTests {
@@ -142,13 +144,16 @@ public class WebFluxSseIntegrationTests {
 		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
 				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
 
-					var messages = List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-							new McpSchema.TextContent("Test message")));
+						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-					var modelPrefs = new McpSchema.ModelPreferences(List.of(), 1.0, 1.0, 1.0);
+								new McpSchema.TextContent("Test message"))))
-
+						.modelPreferences(ModelPreferences.builder()
-					var craeteMessageRequest = new McpSchema.CreateMessageRequest(messages, modelPrefs, null,
+							.hints(List.of())
-							McpSchema.CreateMessageRequest.ContextInclusionStrategy.NONE, null, 100, List.of(),
+							.costPriority(1.0)
-							Map.of());
+							.speedPriority(1.0)
+							.intelligencePriority(1.0)
+							.build())
+						.build();
 
 					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
 						assertThat(result).isNotNull();

mcp-spring/mcp-spring-webmvc/src/test/java/io/modelcontextprotocol/server/WebMvcSseIntegrationTests.java

@@ -20,6 +20,7 @@ import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageRequest;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageResult;
 import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+import io.modelcontextprotocol.spec.McpSchema.ModelPreferences;
 import io.modelcontextprotocol.spec.McpSchema.Role;
 import io.modelcontextprotocol.spec.McpSchema.Root;
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
@@ -45,6 +46,7 @@ import org.springframework.web.servlet.function.ServerResponse;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.awaitility.Awaitility.await;
+import static org.junit.Assert.assertThat;
 import static org.mockito.Mockito.mock;
 
 public class WebMvcSseIntegrationTests {
@@ -199,13 +201,16 @@ public class WebMvcSseIntegrationTests {
 		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
 				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
 
-					var messages = List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-							new McpSchema.TextContent("Test message")));
+						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-					var modelPrefs = new McpSchema.ModelPreferences(List.of(), 1.0, 1.0, 1.0);
+								new McpSchema.TextContent("Test message"))))
-
+						.modelPreferences(ModelPreferences.builder()
-					var craeteMessageRequest = new McpSchema.CreateMessageRequest(messages, modelPrefs, null,
+							.hints(List.of())
-							McpSchema.CreateMessageRequest.ContextInclusionStrategy.NONE, null, 100, List.of(),
+							.costPriority(1.0)
-							Map.of());
+							.speedPriority(1.0)
+							.intelligencePriority(1.0)
+							.build())
+						.build();
 
 					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
 						assertThat(result).isNotNull();

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

@@ -5,6 +5,7 @@
 package io.modelcontextprotocol.spec;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -767,11 +768,57 @@ public final class McpSchema {
 	@JsonProperty("costPriority") Double costPriority,
 	@JsonProperty("speedPriority") Double speedPriority,
 	@JsonProperty("intelligencePriority") Double intelligencePriority) {
-	} // @formatter:on
+	
+	public static Builder builder() {
+		return new Builder();
+	}
+
+	public static class Builder {
+		private List<ModelHint> hints;
+		private Double costPriority;
+		private Double speedPriority;
+		private Double intelligencePriority;
+
+		public Builder hints(List<ModelHint> hints) {
+			this.hints = hints;
+			return this;
+		}
+
+		public Builder addHint(String name) {
+			if (this.hints == null) {
+				this.hints = new ArrayList<>();
+			}
+			this.hints.add(new ModelHint(name));
+			return this;
+		}
+
+		public Builder costPriority(Double costPriority) {
+			this.costPriority = costPriority;
+			return this;
+		}
+
+		public Builder speedPriority(Double speedPriority) {
+			this.speedPriority = speedPriority;
+			return this;
+		}
+
+		public Builder intelligencePriority(Double intelligencePriority) {
+			this.intelligencePriority = intelligencePriority;
+			return this;
+		}
+
+		public ModelPreferences build() {
+			return new ModelPreferences(hints, costPriority, speedPriority, intelligencePriority);
+		}
+	}
+} // @formatter:on
 
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
 	@JsonIgnoreProperties(ignoreUnknown = true)
 	public record ModelHint(@JsonProperty("name") String name) {
+		public static ModelHint of(String name) {
+			return new ModelHint(name);
+		}
 	}
 
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)
@@ -799,6 +846,66 @@ public final class McpSchema {
 			@JsonProperty("thisServer") THIS_SERVER,
 			@JsonProperty("allServers") ALL_SERVERS
 		}
+		
+		public static Builder builder() {
+			return new Builder();
+		}
+
+		public static class Builder {
+			private List<SamplingMessage> messages;
+			private ModelPreferences modelPreferences;
+			private String systemPrompt;
+			private ContextInclusionStrategy includeContext;
+			private Double temperature;
+			private int maxTokens;
+			private List<String> stopSequences;
+			private Map<String, Object> metadata;
+
+			public Builder messages(List<SamplingMessage> messages) {
+				this.messages = messages;
+				return this;
+			}
+
+			public Builder modelPreferences(ModelPreferences modelPreferences) {
+				this.modelPreferences = modelPreferences;
+				return this;
+			}
+
+			public Builder systemPrompt(String systemPrompt) {
+				this.systemPrompt = systemPrompt;
+				return this;
+			}
+
+			public Builder includeContext(ContextInclusionStrategy includeContext) {
+				this.includeContext = includeContext;
+				return this;
+			}
+
+			public Builder temperature(Double temperature) {
+				this.temperature = temperature;
+				return this;
+			}
+
+			public Builder maxTokens(int maxTokens) {
+				this.maxTokens = maxTokens;
+				return this;
+			}
+
+			public Builder stopSequences(List<String> stopSequences) {
+				this.stopSequences = stopSequences;
+				return this;
+			}
+
+			public Builder metadata(Map<String, Object> metadata) {
+				this.metadata = metadata;
+				return this;
+			}
+
+			public CreateMessageRequest build() {
+				return new CreateMessageRequest(messages, modelPreferences, systemPrompt,
+					includeContext, temperature, maxTokens, stopSequences, metadata);
+			}
+		}
 	}// @formatter:on
 
 	@JsonInclude(JsonInclude.Include.NON_ABSENT)

mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java

@@ -21,6 +21,7 @@ import io.modelcontextprotocol.spec.McpSchema.ClientCapabilities;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageRequest;
 import io.modelcontextprotocol.spec.McpSchema.CreateMessageResult;
 import io.modelcontextprotocol.spec.McpSchema.InitializeResult;
+import io.modelcontextprotocol.spec.McpSchema.ModelPreferences;
 import io.modelcontextprotocol.spec.McpSchema.Role;
 import io.modelcontextprotocol.spec.McpSchema.Root;
 import io.modelcontextprotocol.spec.McpSchema.ServerCapabilities;
@@ -162,13 +163,16 @@ public class HttpServletSseServerTransportProviderIntegrationTests {
 		McpServerFeatures.AsyncToolSpecification tool = new McpServerFeatures.AsyncToolSpecification(
 				new McpSchema.Tool("tool1", "tool1 description", emptyJsonSchema), (exchange, request) -> {
 
-					var messages = List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
+					var craeteMessageRequest = McpSchema.CreateMessageRequest.builder()
-							new McpSchema.TextContent("Test message")));
+						.messages(List.of(new McpSchema.SamplingMessage(McpSchema.Role.USER,
-					var modelPrefs = new McpSchema.ModelPreferences(List.of(), 1.0, 1.0, 1.0);
+								new McpSchema.TextContent("Test message"))))
-
+						.modelPreferences(ModelPreferences.builder()
-					var craeteMessageRequest = new McpSchema.CreateMessageRequest(messages, modelPrefs, null,
+							.hints(List.of())
-							McpSchema.CreateMessageRequest.ContextInclusionStrategy.NONE, null, 100, List.of(),
+							.costPriority(1.0)
-							Map.of());
+							.speedPriority(1.0)
+							.intelligencePriority(1.0)
+							.build())
+						.build();
 
 					StepVerifier.create(exchange.createMessage(craeteMessageRequest)).consumeNextWith(result -> {
 						assertThat(result).isNotNull();

mcp/src/test/java/io/modelcontextprotocol/spec/McpSchemaTests.java

@@ -524,10 +524,16 @@ public class McpSchemaTests {
 		Map<String, Object> metadata = new HashMap<>();
 		metadata.put("session", "test-session");
 
-		McpSchema.CreateMessageRequest request = new McpSchema.CreateMessageRequest(Collections.singletonList(message),
+		McpSchema.CreateMessageRequest request = McpSchema.CreateMessageRequest.builder()
-				preferences, "You are a helpful assistant",
+			.messages(Collections.singletonList(message))
-				McpSchema.CreateMessageRequest.ContextInclusionStrategy.THIS_SERVER, 0.7, 1000,
+			.modelPreferences(preferences)
-				Arrays.asList("STOP", "END"), metadata);
+			.systemPrompt("You are a helpful assistant")
+			.includeContext(McpSchema.CreateMessageRequest.ContextInclusionStrategy.THIS_SERVER)
+			.temperature(0.7)
+			.maxTokens(1000)
+			.stopSequences(Arrays.asList("STOP", "END"))
+			.metadata(metadata)
+			.build();
 
 		String value = mapper.writeValueAsString(request);
 
@@ -543,8 +549,12 @@ public class McpSchemaTests {
 	void testCreateMessageResult() throws Exception {
 		McpSchema.TextContent content = new McpSchema.TextContent("Assistant response");
 
-		McpSchema.CreateMessageResult result = new McpSchema.CreateMessageResult(McpSchema.Role.ASSISTANT, content,
+		McpSchema.CreateMessageResult result = McpSchema.CreateMessageResult.builder()
-				"gpt-4", McpSchema.CreateMessageResult.StopReason.END_TURN);
+			.role(McpSchema.Role.ASSISTANT)
+			.content(content)
+			.model("gpt-4")
+			.stopReason(McpSchema.CreateMessageResult.StopReason.END_TURN)
+			.build();
 
 		String value = mapper.writeValueAsString(result);