Behavior-First Planning

Quick Ref: Turn an intent into beads that each carry a runnable acceptance test defining "done". The generative discipline behind the bdd-foundry workflow — extracted here so behavior-first planning survives independent of any orchestrator. Output: frozen Gherkin → executed-red tests → derived spec → an acceptance-gated bead DAG.

YOU MUST EXECUTE THIS DISCIPLINE. Do not just describe it.

Why this exists — the 3/10 problem

Spec-first planning ships beads with no done-criteria: a title, a paragraph of "why", and nothing a machine can run to decide it is finished. The implementer then invents the bar, and "done" becomes a self-grade. Behavior-first planning inverts the order: define the behavior as an executable test before the design, so every bead is born with a runnable contract. The rule is absolute — no runnable acceptance test, no bead.

This is the successor to plain decomposition (plan): same DAG output, but each unit carries a failing test that has actually been run red, not prose. It is the planning-side mirror of the membrane (docs/architecture/control-loop-model.md): the bead's gate is deterministic ground truth, not an opinion.

The four phases (run in order)

Phase 1 — Behaviors: define DONE first

Turn the intent into concrete, testable Gherkin scenarios — Given/When/Then — covering the happy path, edge cases, AND error/failure paths. Every clause must be specific enough to become a runnable test; "works correctly" is rejected.