ADR 0004 — Capture golden responses from the running demo before writing any adapter

Status: accepted · Date: 2026-09-19 · Sprint: 1

Context

The instruction is that current features must not break. The current behaviour is under-documented and under-tested (9 test files across the two backends, ~20,200 LoC), so “don’t break it” cannot be verified by reading.

Decision

Before the first adapter is written, tooling/capture_golden.py drives the live CE-RISE-Demo across every endpoint, every example DPP and the three broken ones, and records the responses to tests/golden/normal/. Normal mode must reproduce them byte-for-byte, normalising only timestamps, correlation ids, latency fields and float noise beyond published precision.

The PEFDPP physics values are locked the same way in tests/golden/pefdpp/.

Consequences

• “No regression” becomes a command that exits 0 or 1.
• Behaviour nobody documented is captured anyway. − Golden tests also lock in current bugs. Any intentional fix must update a golden file in the same commit, with the reason in the message — which is the point: a deliberate change is visible in review.