feat: polish assistant conversations

apps/nextjs/src/app/api/assistant/chat/assistant-chat-input.spec.ts

@@ -11,7 +11,7 @@ describe("assistant chat input", () => {
           parts: [
             {
               type: "text",
-              text: "Check :integration[integration-1]{name=Media server} on :board[board-1]",
+              text: "Check :integration[Media server]{name=integration-1} on :board[Home]{name=board-1}",
             },
           ],
         },

apps/nextjs/src/app/api/assistant/chat/assistant-chat-input.ts

@@ -3,7 +3,7 @@ export type AssistantMentionReference = {
   id: string;
 };
 
-const mentionPattern = /:(app|integration|board|widget)\[([^\]\n]{1,1024})\](?:\{name=[^}\n]{1,1024}\})?/gu;
+const mentionPattern = /:(app|integration|board|widget)\[([^\]\n]{1,1024})\](?:\{name=([^}\n]{1,1024})\})?/gu;
 
 const getMessageText = (message: { parts: unknown[] }) =>
   message.parts
@@ -20,7 +20,9 @@ export const getRequestedMentionIds = (messages: { role: "user" | "assistant"; p
     if (message.role !== "user") continue;
     for (const match of getMessageText(message).matchAll(mentionPattern)) {
       const type = match[1] as AssistantMentionReference["type"];
-      const id = match[2];
+      // assistant-ui stores the display label between brackets and the stable entity ID in `name`.
+      // Keep the bracket value as a fallback for older messages written before named directives.
+      const id = match[3] ?? match[2];
       if (id) mentions.set(`${type}:${id}`, { type, id });
       if (mentions.size >= 30) return [...mentions.values()];
     }

apps/nextjs/src/app/api/assistant/chat/route.ts

@@ -646,6 +646,7 @@ export async function POST(request: Request) {
 
     return result.toUIMessageStreamResponse<UIMessage<AssistantMessageMetadata>>({
       originalMessages: parsed.data.messages as UIMessage<AssistantMessageMetadata>[],
+      sendReasoning: true,
       messageMetadata: ({ part }) => {
         const common = {
           requestId,
@@ -682,7 +683,11 @@ export async function POST(request: Request) {
           latestStep?.inputTokens !== undefined && latestStep.outputTokens !== undefined
             ? latestStep.inputTokens + latestStep.outputTokens
             : undefined;
-        const contextUsed = latestContextUsed ?? (usage.inputTokens ?? 0) + (usage.outputTokens ?? 0);
+        const contextUsed =
+          latestContextUsed ??
+          (usage.inputTokens !== undefined || usage.outputTokens !== undefined
+            ? (usage.inputTokens ?? 0) + (usage.outputTokens ?? 0)
+            : undefined);
         const promptPrice = asFiniteNumber(selectedModel?.promptPrice);
         const completionPrice = asFiniteNumber(selectedModel?.completionPrice);
         const estimatedCost =
@@ -721,8 +726,8 @@ export async function POST(request: Request) {
               ...(outputTokensPerSecond !== undefined ? { outputTokensPerSecond } : {}),
               ...(providerOutputTokensPerSecond !== undefined ? { providerOutputTokensPerSecond } : {}),
               ...(providerGenerationTimeMs !== undefined ? { generationTimeMs: providerGenerationTimeMs } : {}),
-              ...(contextUsed > 0 ? { contextUsed } : {}),
-              ...(selectedModel?.contextLength && contextUsed > 0
+              ...(contextUsed !== undefined && contextUsed > 0 ? { contextUsed } : {}),
+              ...(selectedModel?.contextLength && contextUsed !== undefined && contextUsed > 0
                 ? { contextUtilization: Math.min(contextUsed / selectedModel.contextLength, 1) }
                 : {}),
               ...(cost !== undefined ? { cost, costType: hasReportedCost ? "reported" : "estimated" } : {}),