Client timeout must cancel multi-provider OCR work

General lesson: In a multi-provider OCR fallback path, a browser timeout is not a server deadline unless cancellation is explicitly propagated through the route and every provider attempt. A client may stop waiting while primary and fallback calls continue, consuming capacity and producing a late result nobody can use. Diagnose stage health separately, then compare the client timeout with the sum of provider deadlines and any retry/ROI work. Applicability: request/response extraction flows with sequential providers. Limit: this identifies a timeout-contract mismatch; it does not by itself explain the provider’s error or prove which customers were affected.

Applies when: A synchronous AI extraction request can try more than one provider or stage under a shorter client timeout. Keywords: OCR fallback browser timeout cancellation provider deadline stuck extraction