chat_completions tool call fixes (#2434)

* chat_completions tool call fixes

* update chat completions test

src/backend/src/routers/puterai/openai/chat_completions.js

@@ -132,6 +132,8 @@ module.exports = eggspress('/openai/v1/chat/completions', {
 
         let buffer = '';
         let usage = null;
+        let toolCallIndex = 0;
+        let sawToolCalls = false;
 
         const sendChunk = (delta, finishReason = null, extra = {}) => {
             const payload = {
@@ -170,9 +172,11 @@ module.exports = eggspress('/openai/v1/chat/completions', {
                     sendChunk({ content: event.text });
                 }
                 if ( event.type === 'tool_use' ) {
+                    sawToolCalls = true;
                     sendChunk({
                         tool_calls: [
                             {
+                                index: toolCallIndex++,
                                 id: event.id,
                                 type: 'function',
                                 function: {
@@ -181,7 +185,7 @@ module.exports = eggspress('/openai/v1/chat/completions', {
                                 },
                             },
                         ],
-                    }, 'tool_calls');
+                    });
                 }
                 if ( event.type === 'usage' ) {
                     usage = event.usage;
@@ -190,7 +194,8 @@ module.exports = eggspress('/openai/v1/chat/completions', {
         });
 
         streamValue.on('end', () => {
-            sendChunk({}, 'stop', usage ? { usage: buildUsage(usage) } : {});
+            const finishReason = sawToolCalls ? 'tool_calls' : 'stop';
+            sendChunk({}, finishReason, usage ? { usage: buildUsage(usage) } : {});
             res.write('data: [DONE]\n\n');
             res.end();
         });

src/backend/src/services/ai/utils/FunctionCalling.js

@@ -54,9 +54,13 @@ export const normalize_tools_object =  (tools) => {
                 fn.parameters ||
                 fn.input_schema;
 
-            normal_fn.parameters = parameters ?? {
-                type: 'object',
-            };
+            if ( !parameters || typeof parameters !== 'object' ) {
+                parameters = { type: 'object' };
+            } else if ( ! parameters.type ) {
+                parameters.type = 'object';
+            }
+
+            normal_fn.parameters = parameters;
 
             if ( parameters.properties ) {
                 parameters = normalize_json_schema(parameters);

src/backend/src/services/ai/utils/Messages.js

@@ -44,6 +44,22 @@ export const normalize_single_message = (message, params = {}) => {
             throw new Error('each message must have a \'content\' property');
         }
     }
+
+    // Normalize OpenAI-style tool results into internal tool_result blocks
+    if ( message.role === 'tool' ) {
+        const tool_use_id = message.tool_call_id || message.tool_use_id || message.id;
+        const tool_content = message.content;
+        message.tool_use_id = tool_use_id;
+        message.content = [
+            {
+                type: 'tool_result',
+                tool_use_id,
+                content: typeof tool_content === 'string'
+                    ? tool_content
+                    : JSON.stringify(tool_content ?? {}),
+            },
+        ];
+    }
     if ( ! Array.isArray(message.content) ) {
         message.content = [message.content];
     }
@@ -90,33 +106,43 @@ export const normalize_messages = (messages, params = {}) => {
         messages[i] = normalize_single_message(messages[i], params);
     }
 
-    // Split messages with tool_use content into separate messages
+    // Split messages with multiple content blocks into separate messages.
+    // Keep assistant tool_use blocks together to preserve OpenAI tool-call ordering.
     // TODO: unit test this
     messages = [...messages];
     for ( let i = 0 ; i < messages.length ; i++ ) {
         let message = messages[i];
         let separated_messages = [];
+        const has_tool_use = message.role === 'assistant' &&
+            message.content?.some(c => c?.type === 'tool_use');
+        if ( has_tool_use ) {
+            separated_messages.push(message);
+            messages.splice(i, 1, ...separated_messages);
+            continue;
+        }
         for ( let j = 0 ; j < message.content.length ; j++ ) {
-            if ( message.content[j].type === 'tool_result' ) {
-                separated_messages.push({
-                    ...message,
-                    content: [message.content[j]],
-                });
-            } else {
-                separated_messages.push({
-                    ...message,
-                    content: [message.content[j]],
-                });
-            }
+            separated_messages.push({
+                ...message,
+                content: [message.content[j]],
+            });
         }
         messages.splice(i, 1, ...separated_messages);
     }
 
     // If multiple messages are from the same role, merge them
+    // but avoid merging tool_use/tool_result messages, since order matters
+    const hasToolContent = (message) => {
+        if ( !message || !Array.isArray(message.content) ) return false;
+        return message.content.some((part) =>
+            part && (part.type === 'tool_use' || part.type === 'tool_result'));
+    };
     let merged_messages = [];
     let current_role = null;
     for ( let i = 0 ; i < messages.length ; i++ ) {
-        if ( current_role === messages[i].role ) {
+        const can_merge = current_role === messages[i].role &&
+            !hasToolContent(messages[i]) &&
+            !hasToolContent(merged_messages[merged_messages.length - 1]);
+        if ( can_merge ) {
             merged_messages[merged_messages.length - 1].content.push(...messages[i].content);
         } else {
             merged_messages.push(messages[i]);
@@ -180,4 +206,4 @@ export const extract_text = (messages) => {
             return '';
         }
     }).join(' ');
-};
+};