incremental-implementation

Break the feature into thin vertical slices where each slice delivers working end-to-end functionality. For each slice, implement the smallest complete piece, run tests, verify the result, commit with a descriptive message, then move to the next slice.

Vertical slicing builds one complete path through the entire stack per increment, such as database plus API plus UI for a single operation. Each slice leaves the system in a working, testable state rather than completing one layer at a time.

Use contract-first slicing when backend and frontend must develop in parallel. Define the API contract first, then implement backend against the contract and frontend against mock data, and finally integrate and test end-to-end.

Skip this approach for single-file, single-function changes where the scope is already minimal. The implement-test-verify-commit cycle adds overhead that provides no benefit when the change is inherently atomic.

Each slice is delegated to a fresh subagent using Workspace inherit mode so commits land on the shared feature branch. Only one writer subagent runs at a time, and the parent verifies each slice committed cleanly before dispatching the next.

A failure circuit breaker halts execution immediately when a slice fails verification, cannot commit, or alters a contract unexpectedly. The next slice is not launched and the issue returns to the parent agent or user for triage.