Scenarios

Two control points, one dependency

New saved-views feature: a fresh API endpoint plus the UI that calls it. Outcome: shipped · 3 days. 4 held · 0 adaptations · 0 escapes

saved-views-fe-be

Two control points, one dependency

New saved-views feature: a fresh API endpoint plus the UI that calls it.

UI NEVER 404ED
The plan — drafted before anyone saw it
Strategy Two control points, sequenced — API dark-launches, UI never leads it
Control points views-api + webapp, parent-child sequence
Gates API 100% dark · 24 h of synthetic calls green
Guardrails 404 rate · endpoint p95 · adoption
Rollback either point breaches → both step back together
Ramp — planned outline, actual fill
dark
10%
50%
100%
The run — from the decision log
T+0m read: diff spans views-api and webapp — UI 404s without the endpointheld
T+2h ramped: API to 100% dark; synthetic calls green for 24 hheld
T+1d identified: feature cohort: 214 dashboard power users — the UI opens thereheld
T+3d done: UI at 100% against an endpoint already proven darkheld
4 held · 0 adaptations · 0 escapes

learnedendpoint-leads-UI saved as this repo’s coordinated-pair template.