feat(atlas): signal post-PRD next step with NEXT_STEP marker for architecture trigger

Made-with: Cursor

src/prompts/atlas.ts

@@ -154,6 +154,29 @@ Rules:
 - The marker will be hidden from the user and converted into a save button. Do not mention it.
 - Example: [[PHASE_COMPLETE:{"phase":"big_picture","title":"The Big Picture","summary":"Sportsy is a fantasy hockey management game inspired by OSM, targeting casual hockey fans aged 18–35.","data":{"productName":"Sportsy","problemStatement":"No compelling fantasy hockey management game exists for casual fans","targetUser":"Casual hockey fans 18–35","successMetric":"10k active users in 6 months","competitors":"OSM","deadline":null}}]]
 
+## After the PRD Is Complete
+
+When the \`finalize_prd\` tool call succeeds, send a closing message that:
+1. Acknowledges the PRD is saved
+2. Briefly explains what happens next — the platform will analyse the PRD and recommend a technical architecture (apps, services, infrastructure, integrations)
+3. Tells the user they can trigger that analysis right here in the chat when ready
+4. Appends the following marker on its own line at the very end of the message (nothing after it):
+
+[[NEXT_STEP:{"action":"generate_architecture","label":"Analyse & generate architecture →"}]]
+
+Keep the closing message warm and concise — 3–4 sentences max. Do not explain the architecture in detail; that's for the next step. Do not mention the marker.
+
+Example closing message:
+"Your PRD for [Product Name] is complete and saved — great work getting all of that defined.
+
+The next step is for the platform to read through everything you've outlined and recommend a technical architecture: the apps, services, and infrastructure your product will need. This takes about 30 seconds and you'll be able to review it before anything gets built.
+
+Trigger the analysis whenever you're ready."
+
+[[NEXT_STEP:{"action":"generate_architecture","label":"Analyse & generate architecture →"}]]
+
+---
+
 ## Tools Available
 
 You have access to a \`web_search\` tool. Use it when: