fix(ai): retry Bun socket drops

closes #6431

packages/ai/CHANGELOG.md

@@ -15,6 +15,7 @@
 - Fixed OpenAI Completions and Responses providers to send `(no tool output)` instead of `(see attached image)` when a tool result has empty text and no image content, preventing the model from hallucinating image attachments.
 - Fixed OpenAI Responses and Azure OpenAI Responses requests to avoid sending `max_output_tokens` values below the provider minimum ([#6265](https://github.com/earendil-works/pi/issues/6265)).
 - Fixed retry classification for Cloudflare 524 timeout responses ([#6239](https://github.com/earendil-works/pi/issues/6239)).
+- Fixed retry classification for Bun fetch socket-drop errors such as `socket connection was closed`, so transient stream disconnects retry automatically ([#6431](https://github.com/earendil-works/pi/issues/6431)).
 - Fixed GitHub Copilot extended context window models (Claude Opus 4.7/4.8, Claude Opus 4.6, Claude Sonnet 4.6/5, Claude Fable 5, GPT-5.3 Codex, GPT-5.4, GPT-5.5) to use `contextWindow: 1000000`, preventing premature compaction and under-budgeting ([#6439](https://github.com/earendil-works/pi/issues/6439)).
 
 ### Added

packages/ai/src/utils/retry.ts

@@ -54,6 +54,7 @@ const RETRYABLE_PROVIDER_ERROR_PATTERN = buildProviderErrorPattern([
 	"upstream.?connect",
 	"reset before headers",
 	"socket hang up",
+	"socket connection was closed",
 	"timed? out",
 	"timeout",
 	"terminated",

packages/ai/test/retry.test.ts

@@ -6,6 +6,8 @@ const openAIExplicitRetryMessage =
 	"An error occurred while processing your request. You can retry your request, or contact us through our help center at help.openai.com if the error persists. Please include the request ID req_******** in your message.";
 const bedrockExplicitRetryMessage =
 	'{"message":"The system encountered an unexpected error during processing. Try your request again."}';
+const bunFetchSocketClosedMessage =
+	"The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()";
 
 describe("provider retry classification", () => {
 	it("matches explicit provider retry guidance", () => {
@@ -21,6 +23,14 @@ describe("provider retry classification", () => {
 		).toBe(true);
 	});
 
+	it("matches Bun fetch socket drop wording", () => {
+		expect(
+			isRetryableAssistantError(
+				fauxAssistantMessage("", { stopReason: "error", errorMessage: bunFetchSocketClosedMessage }),
+			),
+		).toBe(true);
+	});
+
 	it("keeps provider limit errors non-retryable", () => {
 		expect(
 			isRetryableAssistantError(