Module payload 

The payload: one binary message per turn, each way.

An input is what a bot receives, an output is what it returns. Each is a short header, then one value per declared item, in declared order, with its byte length in front. Elements are little-endian.

"BSP" kind(u8: b'I' | b'O') payload_schema_version(u32)
repeat per declared value: byte_len(u32) elements…

check_output is the host’s one validity rule for an output: the header, every value’s exact length, and every element finite and inside its declared bounds. Anything else is rejected, and the seat gets the arena’s no-action. Nothing is clamped or corrected.

Enums

Kind

Which way a payload goes.

PayloadError

Why a payload was rejected.

Values

One value’s elements, typed as declared.

Functions

check

Decode and check a payload: structure, finiteness and bounds. This is the host’s whole validity rule.

check_output

The host’s check on one seat’s output.

decode

Decode a payload against its declaration, checking only its structure.

encode

Encode values, one per declared value, in declared order.

encoded_len

The exact encoded size of a payload of these values.

extremes

Every element at its lower or upper bound, chosen by pick: the bang-bang extremes fuzzing plays.

sample_uniform

Values drawn uniformly inside each element’s declared bounds, from a source of random u64s. What a random bot plays, and what fuzzing starts from.