The three things drift is measured against. No watch begins without a goal and at least one checkable criterion — missing anchors are W0, the first wandering signal.
Iterations
Paste each revision as it's produced. Argus measures the delta against the previous one — length, and change magnitude from a real character-bigram similarity. Mark whether each criterion actually moved. The signals read these, not your word for it.
no revisions logged — begin a watch, then paste v1
Chaos signals
Each fires only on evidence Argus can compute. C1 was impossible for the original spec — it had no baseline to compare against. This one snapshots your anchors and watches them.
ARGUS EVENT HORIZON — HUMAN DIRECTION REQUIRED
Why stop now · last safe fork
Signals triggered
What is drifting
Unrepairable if continued
Repair · choose one
Resume gate — confirm to unlock
What this is, said plainly: Argus measures drift from the bytes you hand it — it cannot watch a model you don't paste, and it has no opinion about whether the work is good, only whether it moved. The terminal line is a lock now, not a wish. When the horizon trips, the iteration log disables until you choose a repair — the original spec's === END PAUSE REPORT === was a line a model promised to print and broke in its first breath; this is a state the instrument enforces. measured, not self-reported · enforced, not requested.