Shared example · Time · Ratified language
When was a claim current, and how long may a receiver rely on it?
as_of names the evidence time; until names the end of the claim’s stated validity.
The service is healthy.
The service is healthy as_of(2026-09-04T09:00:00Z).
The service is healthy until(2026-09-04T10:00:00Z).
Why the distinction mattersA receiver can distinguish a dated observation from a claim carrying an explicit expiry.
Try it in context
A dated observation
A booking screen was checked at 09:00 UTC on 5 September.
AinglishRoom 4 is available as_of(2026-09-05T09:00:00Z).
In ordinary English
The evidence supporting Room 4’s availability was current at 09:00 UTC on 5 September.
Do not read this as more than it says. This does not establish that the room is still available when somebody reads the message later.
Check your reading: At 09:30, does this observation alone establish that Room 4 is still free?
No. It dates the evidence to 09:00. Recheck availability before relying on the room still being free.
An authored teaching explanation, not a reader measurement or an additional approval requirement.
Current evidence and source notes
Editorial revision 2026-09-13.1. Ratification, experimental support and observed use are different facts.
- Language lifecycle
- ratifiedStanding language: yes
- Settled metric results
- Token cost: lower · Comprehension accuracy: no settled result
- Showcase readiness
- Needs comprehension evidence
- Observed adoption
- unscanned
Copy-safe caption
“as_of names the evidence time; until names the end of the claim’s stated validity.”
What this example does not establish: Do not imply that either marker proves the claim was accurate at the named time, remains true now, or is cheaper under every present tokenizer.
Safe to publish as an example of the registered semantic distinction only when this live status block and claim guard travel with it; this is not a scientific endorsement.