perf(bot): trim dm assistant response latency

apps/bot/src/openai-chat-assistant.test.ts

@@ -0,0 +1,62 @@
+import { describe, expect, test } from 'bun:test'
+
+import { createOpenAiChatAssistant } from './openai-chat-assistant'
+
+interface CapturedAssistantRequest {
+  model: string
+  max_output_tokens: number
+  input: Array<{ role: string; content: string }>
+}
+
+function successfulResponse(payload: unknown): Response {
+  return new Response(JSON.stringify(payload), {
+    status: 200,
+    headers: {
+      'content-type': 'application/json'
+    }
+  })
+}
+
+describe('createOpenAiChatAssistant', () => {
+  test('caps output tokens and asks for concise replies', async () => {
+    const assistant = createOpenAiChatAssistant('test-key', 'gpt-5-mini', 20_000)
+    expect(assistant).toBeDefined()
+
+    const originalFetch = globalThis.fetch
+    let capturedBody: CapturedAssistantRequest | null = null
+
+    globalThis.fetch = (async (_input: Request | string | URL, init?: RequestInit) => {
+      capturedBody = init?.body ? (JSON.parse(String(init.body)) as CapturedAssistantRequest) : null
+
+      return successfulResponse({
+        output_text: 'Hi.',
+        usage: {
+          input_tokens: 100,
+          output_tokens: 1,
+          total_tokens: 101
+        }
+      })
+    }) as unknown as typeof fetch
+
+    try {
+      const reply = await assistant!.respond({
+        locale: 'en',
+        householdContext: 'Household: Kojori House',
+        memorySummary: null,
+        recentTurns: [],
+        userMessage: 'Hello'
+      })
+
+      expect(reply.text).toBe('Hi.')
+      expect(capturedBody).not.toBeNull()
+      expect(capturedBody!.max_output_tokens).toBe(220)
+      expect(capturedBody!.model).toBe('gpt-5-mini')
+      expect(capturedBody!.input[0]).toMatchObject({
+        role: 'system',
+        content: expect.stringContaining('Default to one to three short sentences.')
+      })
+    } finally {
+      globalThis.fetch = originalFetch
+    }
+  })
+})