title Workflow Sequence Diagram (Guide) version 1.1.0 created 2026-06-20 updated 2026-06-20 owner architect reviewers developer status approved tags process sequence audience developers tier T1 related ../../data/api-contract/example.yaml ../entity-state/example.md ../activity-diagram/example.md ../../DIAGRAMS.md Guide — Workflow Sequence Create for each P1 user story. Link to api-contract. When to use Sequence Message order between actors/systems over time API calls, webhooks, request/response flows When to use other behavior diagrams Need Use instead Entity lifecycle states Entity State Internal process steps and decisions Activity Persistent structure ERD Sequence = who talks to whom and when. Activity = what steps happen. ESD = what states result. Priority by tier Tier Priority T1 Recommended T2+ Critical for P1 flows Full matrix: DIAGRAMS.md Pair with api-contract/example.yaml — sequence exercises the OpenAPI operations.