fix(ai): retry "The upstream provider returned an error"

closes #10842

packages/ai/CHANGELOG.md

@@ -12,6 +12,7 @@
 - Fixed Mistral streams being aborted mid-generation (e.g. during long thinking) after the request timeout; the timeout now applies only to waiting for response headers ([#10609](https://github.com/earendil-works/pi/issues/10609))
 - Fixed OpenRouter router models such as `openrouter/auto` showing a cost of -$1,000,000 per 1M tokens; OpenRouter's negative placeholder prices are now 0
 - Fixed Anthropic `strict: "prefer"` tools failing when the provider rejects the strict tool set for grammar size, tool count, or union limits; requests now retry once with preferred tools non-strict while keeping `strict: "require"` tools strict ([#10409](https://github.com/earendil-works/pi/issues/10409))
+- Fixed "The upstream provider returned an error" not being retried as a transient provider error ([#10842](https://github.com/earendil-works/pi/issues/10842))
 
 ## [1.1.0] - 2026-10-07
 

packages/ai/src/utils/retry.ts

@@ -48,8 +48,9 @@ const RETRYABLE_PROVIDER_ERROR_PATTERN = buildProviderErrorPattern([
 	"internal.?error",
 
 	// Wrapper/provider text for transient upstream failures, including OpenRouter
-	// "Provider returned error" responses (#2264).
-	"provider.?returned.?error",
+	// "Provider returned error" responses (#2264) and gateway wording such as
+	// "The upstream provider returned an error" (#10842).
+	"provider.?returned.?(?:an.?)?error",
 	"exceeded request buffer limit while retrying upstream",
 
 	// Network, proxy, and fetch transport failures. This includes OpenAI Codex