Atlas: opening message, isInit flag, strip trigger from history

- Add opening message instruction to atlas prompt
- Handle isInit flag in atlasChat() to not store the greeting trigger
  as a user turn in conversation history
- Update server.ts to pass is_init through to atlasChat()

Made-with: Cursor

src/atlas.ts

@@ -73,6 +73,8 @@ export async function atlasChat(
     ctx: ToolContext,
     opts?: {
         preloadedHistory?: LLMMessage[];
+        /** When true, the user message is an internal init trigger and should not be stored in history */
+        isInit?: boolean;
     }
 ): Promise<AtlasChatResult> {
     const llm = createLLM(process.env.ATLAS_MODEL ?? 'A', { temperature: 0.5 });
@@ -86,7 +88,10 @@ export async function atlasChat(
     const oaiTools = toOAITools(ATLAS_TOOLS);
     const systemPrompt = resolvePrompt('atlas');
 
-    session.history.push({ role: 'user', content: userMessage });
+    // For init triggers, don't add the synthetic prompt as a user turn
+    if (!opts?.isInit) {
+        session.history.push({ role: 'user', content: userMessage });
+    }
 
     const buildMessages = (): LLMMessage[] => [
         { role: 'system', content: systemPrompt },