One vertical slice at a time — fully working before the next begins
A phase is complete when all conditions are met — not before
All specialists in the phase have passed the activation checklist — including deliberate break-testing of every ask and act call, confirmation that the secondary review model correctly gates all irreversible actions, and a full audit log review showing no unexpected side effects.
The role has been used in real daily life for a sustained period without critical failures. Lab testing is necessary but not sufficient — real-world use surfaces edge cases that testing never reaches.
Documentation is up to date and the specialist registry reflects the current state. A phase is not complete if the documentation doesn't match what was actually built — the registry is the source of truth for the reasoning loop.
While a phase is in daily use, the following can run in parallel without violating the iterative principle: infrastructure improvements, manifest refinement, drafting (but not activating) the next phase's specialists, and security or monitoring improvements.