docs(consultation): Gemini round 2 response — BuiltByBit two-listing architecture

Two separate listings, one webhook, tier detection via resource_id.
Phase 11 spec is now COMPLETE. Ready for Code to build.

Claude (Chronicler #83 - The Compiler) <claude@firefrostgaming.com>

docs/consultations/gemini-modpackchecker-phase11-round2-2026-04-12.md

@@ -89,3 +89,25 @@ Which approach does BuiltByBit's webhook system support? This is the key impleme
 Thanks Gemini! Once we nail down the tier detection from BuiltByBit, we have everything needed for Code to build the complete system. 🔥❄️
 
 — Michael + Claude (Chronicler #83 — The Compiler)
+
+---
+
+## Gemini's Response — Round 2 (April 12, 2026)
+
+**Summary:** BuiltByBit does NOT support pricing variants on a single listing. Must create two separate listings. One webhook endpoint handles both by checking resource_id.
+
+### Key Decision:
+- **Option B confirmed:** Two separate BuiltByBit listings (Standard $14.99, Professional $24.99)
+- Both point to same webhook URL: `POST /api/mvc/webhook/bbb`
+- Arbiter determines tier by matching `resource_id` from payload against env vars
+- `BBB_STANDARD_RESOURCE_ID` and `BBB_PRO_RESOURCE_ID` in Arbiter's `.env`
+
+### Implementation Flow:
+1. Customer buys on BuiltByBit → webhook fires to Arbiter
+2. Arbiter checks resource_id → determines tier → inserts into `mvc_licenses` with tier
+3. Customer installs extension → enters Order ID → calls `/api/mvc/activate`
+4. Arbiter returns `{"status": "success", "tier": "professional"}`
+5. Extension enables features based on tier
+
+### Status: COMPLETE SPEC ✅
+All questions answered. Ready for implementation.