Keeps subscription SaaS vision from PRD while adding accurate as-is
analysis of existing code. Each story now has an "As-Is" table showing
what exists and where the gaps are.
Key points:
- Story 3.5: Transition from BYOK to system-managed models with token
billing. BYOK stays for self-hosted mode (deployment_mode=self-hosted),
system models + subscription quota for hosted mode.
- Story 5.1: Pricing UI exists (Free/PAYG/Enterprise) but needs redesign
to subscription tiers (Free/Pro) with monthly/yearly toggle.
- Story 5.2: PAYG checkout exists (mode=payment), need NEW subscription
endpoint (mode=subscription) with stripe_customer_id binding.
- Story 5.3: Webhook infrastructure exists (signature verify, PAYG handlers).
Need subscription event handlers (customer.subscription.*) alongside.
- Story 5.4: PageLimitService fully implemented. Gap is HTTP-layer pre-check,
plan-based limits, frontend quota indicator, and 402 error handling.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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