feat(formatter): support both reasoning_content and reasoning fields for deserialization (#1086)

Author: LearningGp

agentscope-core/src/main/java/io/agentscope/core/formatter/dashscope/dto/DashScopeMessage.java

@@ -15,6 +15,7 @@
  */
 package io.agentscope.core.formatter.dashscope.dto;
 
+import com.fasterxml.jackson.annotation.JsonAlias;
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonInclude;
@@ -79,6 +80,7 @@ public class DashScopeMessage {
 
     /** Reasoning/thinking content (for assistant messages with thinking enabled). */
     @JsonProperty("reasoning_content")
+    @JsonAlias("reasoning")
     private String reasoningContent;
 
     /** Cache control configuration for prompt caching. */

agentscope-core/src/main/java/io/agentscope/core/formatter/openai/dto/OpenAIMessage.java

@@ -15,6 +15,7 @@
  */
 package io.agentscope.core.formatter.openai.dto;
 
+import com.fasterxml.jackson.annotation.JsonAlias;
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonInclude;
@@ -76,10 +77,12 @@ public class OpenAIMessage {
     private List<OpenAIToolCall> toolCalls;
 
     /**
-     * Reasoning/thinking content (for o1 and similar reasoning models).
-     * This field contains the model's internal reasoning process.
+     * Reasoning/thinking content from the model.
+     * Accepts both {@code reasoning_content} (commercial APIs like DeepSeek, DashScope) and
+     * {@code reasoning} (vLLM deployments) during deserialization.
      */
     @JsonProperty("reasoning_content")
+    @JsonAlias("reasoning")
     private String reasoningContent;
 
     /**

agentscope-core/src/test/java/io/agentscope/core/formatter/openai/dto/OpenAIMessageReasoningFieldTest.java

@@ -0,0 +1,171 @@
+/*
+ * Copyright 2024-2026 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.agentscope.core.formatter.openai.dto;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import io.agentscope.core.util.JsonCodec;
+import io.agentscope.core.util.JsonUtils;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for OpenAIMessage reasoning field compatibility.
+ *
+ * <p>Verifies that both {@code reasoning_content} (commercial APIs) and {@code reasoning}
+ * (vLLM) are correctly deserialized into {@code reasoningContent} via {@code @JsonAlias}.
+ */
+@Tag("unit")
+@DisplayName("OpenAIMessage Reasoning Field Compatibility")
+class OpenAIMessageReasoningFieldTest {
+
+    private JsonCodec jsonCodec;
+
+    @BeforeEach
+    void setUp() {
+        jsonCodec = JsonUtils.getJsonCodec();
+    }
+
+    @Test
+    @DisplayName("Should deserialize reasoning_content from commercial APIs")
+    void testDeserializeReasoningContent() {
+        String json =
+                """
+                {
+                  "role": "assistant",
+                  "reasoning_content": "Let me analyze this step by step...",
+                  "content": "The answer is 42."
+                }
+                """;
+
+        OpenAIMessage message = jsonCodec.fromJson(json, OpenAIMessage.class);
+
+        assertEquals("Let me analyze this step by step...", message.getReasoningContent());
+        assertEquals("The answer is 42.", message.getContentAsString());
+    }
+
+    @Test
+    @DisplayName("Should deserialize reasoning from vLLM deployments via @JsonAlias")
+    void testDeserializeReasoning() {
+        String json =
+                """
+                {
+                  "role": "assistant",
+                  "reasoning": "First, I need to consider the problem...",
+                  "content": "The result is 7."
+                }
+                """;
+
+        OpenAIMessage message = jsonCodec.fromJson(json, OpenAIMessage.class);
+
+        assertEquals("First, I need to consider the problem...", message.getReasoningContent());
+        assertEquals("The result is 7.", message.getContentAsString());
+    }
+
+    @Test
+    @DisplayName("Should handle null reasoning fields gracefully")
+    void testDeserializeWithoutReasoning() {
+        String json =
+                """
+                {
+                  "role": "assistant",
+                  "content": "Simple response without thinking."
+                }
+                """;
+
+        OpenAIMessage message = jsonCodec.fromJson(json, OpenAIMessage.class);
+
+        assertNull(message.getReasoningContent());
+    }
+
+    @Test
+    @DisplayName("Should deserialize reasoning from vLLM streaming delta")
+    void testDeserializeVllmStreamingDelta() {
+        String json =
+                """
+                {
+                  "role": "assistant",
+                  "reasoning": "Thinking chunk...",
+                  "content": null
+                }
+                """;
+
+        OpenAIMessage delta = jsonCodec.fromJson(json, OpenAIMessage.class);
+
+        assertEquals("Thinking chunk...", delta.getReasoningContent());
+        assertNull(delta.getContentAsString());
+    }
+
+    @Test
+    @DisplayName("Should deserialize full vLLM-style response")
+    void testDeserializeFullVllmResponse() {
+        String json =
+                """
+                {
+                  "id": "chatcmpl-vllm-123",
+                  "object": "chat.completion",
+                  "choices": [
+                    {
+                      "index": 0,
+                      "message": {
+                        "role": "assistant",
+                        "reasoning": "Comparing decimals...",
+                        "content": "9.8 is greater as a decimal number."
+                      },
+                      "finish_reason": "stop"
+                    }
+                  ]
+                }
+                """;
+
+        OpenAIResponse response = jsonCodec.fromJson(json, OpenAIResponse.class);
+        OpenAIMessage message = response.getFirstChoice().getMessage();
+
+        assertEquals("Comparing decimals...", message.getReasoningContent());
+        assertTrue(message.getContentAsString().contains("9.8 is greater"));
+    }
+
+    @Test
+    @DisplayName("Should deserialize full vLLM streaming chunk")
+    void testDeserializeVllmStreamingChunk() {
+        String json =
+                """
+                {
+                  "id": "chatcmpl-vllm-456",
+                  "object": "chat.completion.chunk",
+                  "choices": [
+                    {
+                      "index": 0,
+                      "delta": {
+                        "role": "assistant",
+                        "reasoning": "Step 1: parse the input..."
+                      },
+                      "finish_reason": null
+                    }
+                  ]
+                }
+                """;
+
+        OpenAIResponse response = jsonCodec.fromJson(json, OpenAIResponse.class);
+        OpenAIMessage delta = response.getFirstChoice().getDelta();
+
+        assertEquals("Step 1: parse the input...", delta.getReasoningContent());
+    }
+}