Async Boundary Hardening

Status: Draft Date: 2026-03-07

Problem

Async API endpoints currently execute significant synchronous work, which can block the event loop and reduce concurrency under load.

Goal

Define and enforce safe async/sync boundaries for chat and quiz execution.

Scope

• Chat execution path
• Quiz execution path
• SSE behavior under load
• Concurrency regression coverage

Open Questions

• Threadpool vs sync-route tradeoff
• Load test threshold for acceptable concurrency behavior