What is Admission control?
Verified 5 August 2026
Conventional search indexes almost everything and relies on ranking to surface the good material. That works when a human reads the results, because a person discards bad results at a glance and at no cost.
An agent cannot. It cannot disambiguate an ambiguous query and cannot triage results without paying for them in context and reasoning tokens. So quality has to move earlier: admit only what is worth returning.
unlob is built on this principle: we admit selectively rather than indexing everything, so a search returns fewer and better hits. The trade is a smaller index, which we treat as something to be honest about — why_not(url) reports whether any URL is present, was removed with a typed reason, or was never admitted. How the admission decision itself is made is not published.
How unlob handles this: How it works
Common questions
What is Admission control?
Admission control decides at index time which documents are worth indexing at all, rather than indexing everything and sorting it out at query time.
How does Admission control work in practice?
An agent cannot. It cannot disambiguate an ambiguous query and cannot triage results without paying for them in context and reasoning tokens. So quality has to move earlier: admit only what is worth returning.
See it working
The free tier is 10,000 requests a month with no card — enough to test any of this against your own queries.