fix(cursor): avoid empty user turns after tool results

src/cursor/cursor-anthropic-translator.ts

@@ -102,6 +102,7 @@ export function translateAnthropicRequest(raw: unknown): TranslatedAnthropicRequ
 
     const textParts: string[] = [];
     const toolCalls: NonNullable<CursorOpenAIMessage['tool_calls']> = [];
+    let sawToolResult = false;
 
     content.forEach((block, blockIndex) => {
       const parsed = assertObject(
@@ -140,6 +141,7 @@ export function translateAnthropicRequest(raw: unknown): TranslatedAnthropicRequ
             `messages[${messageIndex}].content[${blockIndex}] tool_result requires user role`
           );
         }
+        sawToolResult = true;
         translatedMessages.push({
           role: 'tool',
           tool_call_id: typeof parsed.tool_use_id === 'string' ? parsed.tool_use_id : '',
@@ -165,7 +167,7 @@ export function translateAnthropicRequest(raw: unknown): TranslatedAnthropicRequ
       return;
     }
 
-    if (textParts.length > 0 || toolCalls.length === 0) {
+    if (textParts.length > 0 || !sawToolResult) {
       translatedMessages.push({
         role,
         content: textParts.join('\n'),

tests/unit/cursor/cursor-anthropic-translator.test.ts

@@ -59,6 +59,36 @@ describe('translateAnthropicRequest', () => {
       })
     ).toThrow('is not supported');
   });
+
+  it('does not append an empty user message after tool_result-only turns', () => {
+    const translated = translateAnthropicRequest({
+      messages: [
+        {
+          role: 'assistant',
+          content: [{ type: 'tool_use', id: 'toolu_1', name: 'search', input: { q: 'x' } }],
+        },
+        {
+          role: 'user',
+          content: [{ type: 'tool_result', tool_use_id: 'toolu_1', content: 'done' }],
+        },
+      ],
+    });
+
+    expect(translated.messages).toEqual([
+      {
+        role: 'assistant',
+        content: '',
+        tool_calls: [
+          {
+            id: 'toolu_1',
+            type: 'function',
+            function: { name: 'search', arguments: '{"q":"x"}' },
+          },
+        ],
+      },
+      { role: 'tool', tool_call_id: 'toolu_1', content: 'done' },
+    ]);
+  });
 });
 
 describe('createAnthropicProxyResponse', () => {