fix #724

Author: overheadhunter

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

@@ -418,6 +418,7 @@ public record Sampling() {
 		 * data from users with optional JSON schemas to validate responses.
 		 */
 		@JsonInclude(JsonInclude.Include.NON_ABSENT)
+		@JsonIgnoreProperties(ignoreUnknown = true)
 		public record Elicitation() {
 		}
 

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

@@ -10,6 +10,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
@@ -353,6 +354,25 @@ void testInitializeResult() throws Exception {
 							{"protocolVersion":"2024-11-05","capabilities":{"logging":{},"prompts":{"listChanged":true},"resources":{"subscribe":true,"listChanged":true},"tools":{"listChanged":true}},"serverInfo":{"name":"test-server","version":"1.0.0"},"instructions":"Server initialized successfully"}"""));
 	}
 
+	@Test
+	// see https://github.com/modelcontextprotocol/java-sdk/issues/724
+	void testParseInitializeRequest() throws IOException {
+		String serialized = """
+				{"protocolVersion":"2024-11-05","capabilities":{"elicitation":{"form":{}}},"clientInfo":{"name":"test-client","version":"1.0.0"},"_meta":{"metaKey":"metaValue"}}
+				""";
+
+		McpSchema.InitializeRequest deserialized = JSON_MAPPER.readValue(serialized, McpSchema.InitializeRequest.class);
+
+		McpSchema.ClientCapabilities capabilities = McpSchema.ClientCapabilities.builder()
+				.elicitation()
+				.build();
+		McpSchema.Implementation clientInfo = new McpSchema.Implementation("test-client", "1.0.0");
+		Map<String, Object> meta = Map.of("metaKey", "metaValue");
+		McpSchema.InitializeRequest expected = new McpSchema.InitializeRequest(ProtocolVersions.MCP_2024_11_05,
+				capabilities, clientInfo, meta);
+		assertThat(deserialized).isEqualTo(expected);
+	}
+
 	// Resource Tests
 
 	@Test