Preserve DeepSeek reasoning for tool calls

Author: jahooma

packages/agent-runtime/src/tools/stream-parser.ts

@@ -276,6 +276,11 @@ export async function processStream(
       }
 
       if (chunk.type === 'reasoning') {
+        if (chunk.text) {
+          assistantMessages.push(
+            assistantMessage({ type: 'reasoning', text: chunk.text }),
+          )
+        }
         onResponseChunk({
           type: 'reasoning_delta',
           text: chunk.text,

packages/internal/src/openai-compatible/chat/convert-to-openai-compatible-chat-messages.test.ts

@@ -509,6 +509,43 @@ describe('provider-specific metadata merging', () => {
     ])
   })
 
+  it('should preserve assistant reasoning content with tool calls', () => {
+    const result = convertToOpenAICompatibleChatMessages([
+      {
+        role: 'assistant',
+        content: [
+          { type: 'reasoning', text: 'Need the date first. ' },
+          { type: 'reasoning', text: 'Then call weather.' },
+          { type: 'text', text: 'Checking that now...' },
+          {
+            type: 'tool-call',
+            toolCallId: 'call1',
+            toolName: 'get_weather',
+            input: { location: 'Hangzhou' },
+          },
+        ],
+      },
+    ])
+
+    expect(result).toEqual([
+      {
+        role: 'assistant',
+        content: 'Checking that now...',
+        reasoning_content: 'Need the date first. Then call weather.',
+        tool_calls: [
+          {
+            id: 'call1',
+            type: 'function',
+            function: {
+              name: 'get_weather',
+              arguments: JSON.stringify({ location: 'Hangzhou' }),
+            },
+          },
+        ],
+      },
+    ])
+  })
+
   it('should handle a single tool role message with multiple tool-result parts', () => {
     const result = convertToOpenAICompatibleChatMessages([
       {

packages/internal/src/openai-compatible/chat/convert-to-openai-compatible-chat-messages.ts

@@ -65,6 +65,7 @@ export function convertToOpenAICompatibleChatMessages(
 
       case 'assistant': {
         let text = ''
+        let reasoningContent = ''
         const toolCalls: Array<{
           id: string
           type: 'function'
@@ -78,6 +79,10 @@ export function convertToOpenAICompatibleChatMessages(
               text += part.text
               break
             }
+            case 'reasoning': {
+              reasoningContent += part.text
+              break
+            }
             case 'tool-call': {
               toolCalls.push({
                 id: part.toolCallId,
@@ -96,6 +101,8 @@ export function convertToOpenAICompatibleChatMessages(
         messages.push({
           role: 'assistant',
           content: text,
+          reasoning_content:
+            reasoningContent.length > 0 ? reasoningContent : undefined,
           tool_calls: toolCalls.length > 0 ? toolCalls : undefined,
           ...metadata,
         })