build

name	build
description	Use to implement a feature or bugfix as small TDD vertical slices that follow the repo's conventions. Produces working, tested code one slice at a time. Reads acceptance criteria and conventions from the Spine.

build — TDD vertical slices

Implement work the way a senior engineer does: smallest valuable slice first, test-first, frequent commits, following the repo's existing patterns.

Steps

1. Read the Spine. Load conventions.md (commands + patterns to follow), context.md (architecture + language), and the acceptance criteria in journal.md. If there are no criteria yet, run align first.
2. Pick the smallest vertical slice that delivers one acceptance criterion end to end.
3. Red: write a failing test that pins the desired behavior. Run it; confirm it fails for the expected reason.
4. Green: write the minimal code to pass. Run the test; confirm it passes.
5. Refactor: improve names and structure with tests green. Favor deep modules with simple interfaces — avoid balls of mud.
6. Commit the slice with a clear message.
7. Update the Spine. In journal.md, tick the criterion, set the next step.
8. Repeat until all criteria are met. Stop and report if a criterion is blocked.

Spine I/O

• Reads: conventions.md, context.md, journal.md.
• Writes: journal.md (progress, next step).

Notes

• Use the test/typecheck commands from conventions.md, not invented ones.
• Name code using the Spine's shared language for consistency.
• Don't claim a slice is done without running its test — that's verify's rule too, applied continuously here.