What is skill brick?
A brick is a compiled path segmented by phase: sign in, navigate, filter, export. Rather than storing one monolithic action list, the engine records the named phases it passed through, so a later run can compose or substitute a phase instead of re-deriving the whole flow, and a repair can target the phase that broke.
Why it matters
A monolithic skill fails as a unit: one changed step invalidates the whole recording. Bricks make the failure local — the phase that no longer fits is the phase that gets re-planned, and the rest still replays.