Function dflash_ctx_cap 

pub fn dflash_ctx_cap() -> usize

2026-09-25: The DFlash context-window bound, in tokens: the most recent target positions the drafter may accumulate. Both the per-sequence ctx accumulator (proposer.rs) and the model’s whole-prompt hidden capture (metrale-model-engine’s impl_a1.rs) are sized from it.

METRALE_DFLASH_CTX_CAP=<tokens> (default 16384); 0 disables the cap.