Replay

For important behavior, PING aims to answer, after the fact:

• What happened?
• Why did it happen, and what information caused it?
• Which authority made the decision?
• Which version of the system executed it?
• Can we reproduce the result, and prove the replay is equivalent?

Replay is therefore not debugging infrastructure. It is institutional memory: the difference between a system that learns and a system that merely runs.

Where PING claims deterministic behavior, determinism is a guarantee, not an implementation detail. Same causal history should produce the same replay ordering, the same execution, the same canonical state, the same canonical bytes, the same hash. Constitutional outputs must not depend accidentally on machine, OS, locale, database ordering, timestamps, or random IDs.

Where nondeterminism is intentional (sampling, timing, external data), it is made explicit and kept outside deterministic constitutional outputs. Accidental nondeterminism is a bug; declared nondeterminism is a design choice.

A witness is a compact, checkable attestation that a particular execution produced a particular canonical result. Witnesses let two parties agree on what happened without re-running the world: compare the witness, compare the hash, and you know whether you are looking at the same history. This is the direction; the full witness protocol is still being designed.

Replay semantics are designed and partially implemented: event ordering, canonical state derivation, and hash-chained attestation exist in prototype form. The end-to-end “replay this decision and prove equivalence” loop is in development. Until it is complete, this page documents the design, not a finished capability.