What is a call site?

A call site is the place in source code where a function is invoked, as distinct from where it is defined. Tessary borrows the term for the place an LLM call or a whole agent loop runs, because that is where a finding, a baseline, and a fix attach.

Tessary resolves a call site from one span attribute and nothing else:

tessary.call_site.id: "<your id>"

Untagged spans still ingest, they just don’t get a call site, so nothing about them accrues to a baseline.

Two call sites doing the same kind of work, summarizing two different documents say, stay separate when they’re different places in your code. The id names the function, not the request, so everything Tessary learns about that function accrues to one place: its normal latency, its normal cost, its normal behavior.