What is Coverage graph?
Verified 5 August 2026
Search engines compute these relationships in order to build an index: the link graph for authority, near-duplicate clusters for deduplication, entity and topic extraction for classification. Almost all of them discard the structure afterwards and return a ranked list.
Publishing it instead lets an agent traverse relationships rather than reconstructing them from ranked lists in its context window. The cost is close to zero, because every input already existed.
unlob exposes six traversal operations over passages, hosts, stories, topics and entities.
How unlob handles this: Coverage graph
Common questions
What is Coverage graph?
A coverage graph is a typed graph over a search index recording how documents relate — who published them, which report the same story, what they are about and who links to whom.
How does Coverage graph work in practice?
Publishing it instead lets an agent traverse relationships rather than reconstructing them from ranked lists in its context window. The cost is close to zero, because every input already existed.
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.