A2.07 · Decomposition · capstone
Workshop: decomposing Portal
Six techniques, one real target. The capstone runs the whole chapter on the Portal’s web surface — and shows the decomposition is not hypothetical: it already happened, rung by rung, in a repository you can read.
A2.01 through A2.06 each taught one move. Here they land where they were actually used: the
Portal’s web surface, built in the companion course as chapter F6
(Phoenix). A one-line vision — serve the Portal to people — was decomposed into nine
vertical rungs (f6.1–f6.9), each a real
capability carried by four artifacts — a roadmap line, a spec, Given/When/Then stories, an agent brief
— built over the unchanged engine and proven before the next began. The slider walks that real roadmap;
the three dives carry the what/why, the how, and the when by hand.
The Portal’s web surface, decomposed for real
The earlier modules taught the moves on toy stories. The capstone applies them where they were actually used:
the Portal’s web surface — chapter F6 in the companion course.
Its one-line vision, serve the Portal to people, was decomposed into nine vertical rungs,
f6.1 through f6.9. Every rung ships one capability a real
role can use, calls only the unchanged Portal facade, and carries its own four
artifacts: a line in phoenix.roadmap.md, a spec f6.N.md,
Given/When/Then acceptance in f6.N.stories.md, and an agent brief
f6.N.llms.md.
Drag the slider to walk the roadmap. The readout answers the four questions a decomposition has to settle for
every rung — what it delivers, when it was specified and shipped (from
the repository’s git history), why (which milestone it serves), and how
it is proven — read straight off the real f6.N files. Each rung is taught and
built as its own chapter in the companion course, under /elixir/phoenix —
the bootstrap at /elixir/phoenix/lifecycle, persistence at
/elixir/phoenix/ecto, and so on through the dashboard.
The F6 web chapter · nine rungs, three milestones · drag to walk the roadmap
A decomposition answers why, what, when, and how for every rung — and a good one leaves that trail in the repository, not only in a plan.
The three dives
Each dive carries part of the decomposition by hand on the real F6 chapter, in the arc what & why → how → when: read the vision into its rung ladder of real stories, show one rung as its four artifacts and its proof, then order the rungs into milestones and watch the specs evolve in git. Read them in order — A2.07.1 starts.
Vision to stories
Read the F6 web vision into its nine-rung value ladder — each rung a real capability and the
actual user story quoted from its f6.N.stories.md.
Split and test
One vision split into nine vertical rungs; one rung shown as its four real artifacts — roadmap, spec, stories, brief — and proven by its Given/When/Then.
Order the backlog
The roadmap lens — nine rungs in three milestones, dependency-ordered and runnable — and the git history of how the specs evolved: specified, shipped, reconciled.
A2.07 closes the chapter on the real thing. The F6 decomposition walked above — nine rungs, four artifacts each, ordered into three milestones — is the kind of backlog Part III, the roadmap layer, plans into delivery. Each rung is then specified, built, and proven in the companion /elixir Phoenix chapter — F6.4 contexts at /elixir/phoenix/contexts, F6.6 LiveView at /elixir/phoenix/liveview; this workshop shows their decomposition. Return to the A2 module navigation to review the techniques it applies.
References
The end-to-end story-and-backlog tradition this capstone draws on, and the chapter modules it runs in sequence.
Sources
- Cohn, M. — User Stories Applied — turning a product vision into a story backlog, end to end.
- Adzic, G. — Specification by Example — deriving a shared, testable backlog from a goal.
- Humble & Farley — Continuous Delivery — a backlog ordered so the system stays releasable at every rung.
Related in this course
- A2.07.1 · Vision to stories
- A2.07.2 · Split and test
- A2.07.3 · Order the backlog
- A2.01 · Value, not tasks — the first move the workshop applies.
- A2.02 · The Connextra form — the story form.
- A2.03 · INVEST — the readiness gate.
- A2 · Decomposition — the chapter.
- Companion · F6 Phoenix chapter — where the nine rungs are specified, built, and proven.
- /elixir/phoenix/contexts — F6.4, the domain behind the facade.
- /elixir/phoenix/liveview — F6.6, the interactive catalog (the rung dive 2 dissects).
- /elixir/phoenix/deployment — F6.8, auth and the deployed release.
- Companion · Functional Programming in Elixir — the Portal’s internals.