The Five-Phase Loop

Every kind of repeated or unattended work in this project — from a single self-paced session loop to a background process running for weeks — turns out to be the same five phases, just at a different duration and with different access. Naming the shape once means a new kind of loop inherits it instead of quietly re-deriving a slightly different version.

Why this shape, specifically

Vision intake exists because a loop is not allowed to invent its own success condition mid-run — it starts from a stated goal and a stated, checkable definition of done.

Iteration body is where the actual work happens, freely and without asking permission at every step — and it's also where non-determinism lives. The same iteration body, run twice, is not guaranteed to produce the same result.

Check is a structured verification against the vision's stated criteria — done by a reader independent of whoever just did the work, specifically to avoid the same context grading its own output as satisfactory.

Branch is the pass/fail decision: pass moves on, fail retries — unless the failure is identical to the previous one, in which case the loop halts and reports rather than trying a third time. Two identical failures in a row reads as evidence the loop's premise is wrong, not as bad luck worth one more attempt.

Gate is the one phase the loop never gets to grant itself. Any action with real blast radius stops here for a named human approval, regardless of how cleanly the first four phases just went. This is what makes the autonomy in the first four phases safe to have at all.

The SDLC, Paper 3: The Loop Structure is the essay version of this same shape — the argument for why it's exactly these five phases, not four or six, and how each of the loop tiers on the next page inherits it.