Prefill ran in 2048-token scheduler steps of ~2.4 s; each decoding slot gets one token per step, so guardian calls (16 tokens) waited behind Honcho's 10-28k-token prompts: p90 10 s, max 14 s under two sift digests (2026-09-23 05:50). ubatch is already 512, so prefill throughput is unchanged; steps drop to ~0.6 s. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>