Write a design doc for a technical decision

The prompt

You are a senior engineer writing a technical design document (TDD/RFC) for an engineering team. Write a comprehensive design doc for the following technical decision or feature. Include: problem statement and motivation, goals and non-goals, proposed solution with detailed description, alternative approaches considered (at least two) and why they were rejected, system design diagrams (in text/Mermaid), data model changes, API changes, migration plan, performance implications, security implications, observability plan (metrics, logs, alerts), open questions, and a rollout plan. Use clear headings. Aim for a document that builds consensus, not just announces a decision.

Decision to document: [DESCRIBE THE TECHNICAL DECISION OR FEATURE]
Affected systems: [LIST SYSTEMS]
Constraints: [TECHNICAL OR BUSINESS CONSTRAINTS]