fix: resume conversation (#346)

apps/agent/lib/conversations/formatConversationHistory.ts

@@ -1,16 +1,24 @@
 import type { UIMessage } from 'ai'
 
 const MAX_MESSAGES = 10
-const MAX_MESSAGE_CHARS = 65536 // 16K context window size
+const MAX_MESSAGE_CHARS = 65536
 
-export function formatConversationHistory(messages: UIMessage[]): string {
-  if (messages.length === 0) return ''
+interface ConversationMessage {
+  role: 'user' | 'assistant'
+  content: string
+}
+
+export function formatConversationHistory(
+  messages: UIMessage[],
+): ConversationMessage[] {
+  if (messages.length === 0) return []
 
   const recentMessages = messages.slice(-MAX_MESSAGES)
 
-  const formatted = recentMessages
+  return recentMessages
     .map((msg) => {
-      const role = msg.role === 'user' ? 'user' : 'assistant'
+      const role: 'user' | 'assistant' =
+        msg.role === 'user' ? 'user' : 'assistant'
       const textContent = msg.parts
         .filter((part) => part.type === 'text')
         .map((part) => part.text)
@@ -18,15 +26,12 @@ export function formatConversationHistory(messages: UIMessage[]): string {
 
       if (!textContent.trim()) return null
 
-      const truncatedContent =
+      const content =
         textContent.length > MAX_MESSAGE_CHARS
           ? `${textContent.slice(0, MAX_MESSAGE_CHARS)}... [truncated]`
           : textContent
 
-      return `<${role}>${truncatedContent}</${role}>`
+      return { role, content }
     })
-    .filter(Boolean)
-    .join('\n\n')
-
-  return formatted
+    .filter((msg): msg is ConversationMessage => msg !== null)
 }

apps/server/src/agent/gemini-agent.ts

@@ -383,36 +383,29 @@ export class GeminiAgent {
     honoStream: HonoSSEStream,
     signal?: AbortSignal,
     browserContext?: BrowserContext,
-    previousConversation?: string,
+    previousConversation?: { role: 'user' | 'assistant'; content: string }[],
   ): Promise<void> {
     const abortSignal = signal || new AbortController().signal
     const promptId = `${this.conversationId}-${Date.now()}`
 
     const contextPrefix = this.formatBrowserContext(browserContext)
 
-    // User query
-    const userQuery = `<USER_QUERY>
-${message}
-</USER_QUERY>`
-
-    // Inject previous conversation if resuming (no server-side history)
-    let fullMessage = userQuery
-    if (previousConversation) {
-      fullMessage = `<previous_conversation>
-The user is resuming a previous conversation. Here is the conversation history for context:
-
-${previousConversation}
-</previous_conversation>
-
-Continue the conversation based on the above context. Here is the user's new message:
-
-${userQuery}`
-      logger.info('Injecting previous conversation for resume', {
+    if (previousConversation?.length) {
+      const historyContents: Content[] = previousConversation.map((msg) => ({
+        role: msg.role === 'assistant' ? 'model' : 'user',
+        parts: [{ text: msg.content }],
+      }))
+      this.client.setHistory(historyContents)
+      logger.info('Restored conversation history for resume', {
         conversationId: this.conversationId,
-        historyLength: previousConversation.length,
+        messageCount: previousConversation.length,
       })
     }
 
+    const fullMessage = `<USER_QUERY>
+${message}
+</USER_QUERY>`
+
     let currentParts: Part[] = [{ text: contextPrefix + fullMessage }]
     let turnCount = 0
 

apps/server/src/api/types.ts

@@ -42,7 +42,14 @@ export const ChatRequestSchema = VercelAIConfigSchema.extend({
   userWorkingDir: z.string().min(1).optional(),
   supportsImages: z.boolean().optional().default(true),
   mode: z.enum(['chat', 'agent']).optional().default('agent'),
-  previousConversation: z.string().optional(),
+  previousConversation: z
+    .array(
+      z.object({
+        role: z.enum(['user', 'assistant']),
+        content: z.string(),
+      }),
+    )
+    .optional(),
 })
 
 export type ChatRequest = z.infer<typeof ChatRequestSchema>