incremental-implementation

Break the feature into thin vertical slices where each slice delivers working end-to-end functionality. For each slice, write a failing test first, implement the minimum code to pass it, verify the build, and commit before moving to the next slice.

Read the todo.md task index first and follow its Current task pointer instead of re-reading the full plan. Open only that task's section in plan.md, flip its checkbox to in-progress, and continue the increment cycle from there.

Vertical slicing builds one complete path through the stack (database, API, UI) per increment, so every slice is testable end-to-end. Horizontal layering builds all of one layer first, leaving nothing demonstrable until the final layer lands.

Skip it for single-file, single-function changes where the scope is already minimal. The per-increment test and commit overhead adds no value when the entire change fits in one small, obvious step.

A test never seen failing may assert the wrong thing, pass on old behavior, or not run at all. Watching it fail confirms the test is an independent check rather than a transcript of code already written.

Feature flags let you merge incomplete increments to the main branch without exposing unfinished work to users. New behavior stays disabled by default and is enabled only when the feature is complete.