Screenshot workflows no longer pay a full conversation re-read per capture. When a request's image set strictly extends the cached one, an append verdict verifies from rank-symmetric inputs (consensus-proven descriptor plus per-image sha256 manifest) that every cached image is byte- and layout-identical, then reuses the verified prefix — a new partial-media input mode feeds only the appended images' pixels alongside the suffix tokens. Changed, reordered, or replaced images fall back to the proven cold rebuild; rank-divergent verdicts collapse to a symmetric full prefill via the prefix-plan consensus with no new collectives. Field results on a live 100k+ agent session: captures that previously cost a ~3-minute full re-read now prefill sub-1k-token suffixes in seconds, across consecutive appends on both ranks in lockstep. Also in this line: runtime updated to mlx-vlm 0.6.6 with the validated custom MLX core preserved.