fix(ai): corrected WebSocket fallback to safely replay buffered output over SSE

- Fixed WebSocket stream fallback logic to safely replay buffered output over SSE when WebSocket fails after partial content has been streamed.
- Added tracking flag to prevent unsafe replays of tool calls and terminal events during fallback transitions.
- Enhanced error recovery to reset output state when replaying buffered content over SSE connection.

packages/ai/CHANGELOG.md

@@ -1,6 +1,9 @@
 # Changelog
 
 ## [Unreleased]
+### Fixed
+
+- Fixed WebSocket stream fallback logic to safely replay buffered output over SSE when WebSocket fails after partial content has been streamed
 
 ## [13.9.4] - 2026-03-07
 ### Changed

packages/ai/src/providers/openai-codex-responses.ts

@@ -504,6 +504,7 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 			let websocketStreamRetries = 0;
 			let providerRetryAttempt = 0;
 			let sawTerminalEvent = false;
+			let canSafelyReplayWebsocketOverSse = true;
 			while (true) {
 				try {
 					for await (const rawEvent of eventStream) {
@@ -674,6 +675,7 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 									name: item.name,
 									arguments: parseStreamingJson(item.arguments || "{}"),
 								};
+								canSafelyReplayWebsocketOverSse = false;
 								stream.push({ type: "toolcall_end", contentIndex: blockIndex(), toolCall, partial: output });
 							}
 						} else if (eventType === "response.created") {
@@ -729,48 +731,72 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 
 					break;
 				} catch (error) {
-					if (
+					const canReplayWebsocketFailureOverSse =
 						usingWebsocket &&
 						websocketState &&
 						isCodexWebSocketRetryableStreamError(error) &&
-						output.content.length === 0 &&
-						!options?.signal?.aborted
-					) {
+						canSafelyReplayWebsocketOverSse &&
+						!sawTerminalEvent &&
+						!options?.signal?.aborted;
+					if (canReplayWebsocketFailureOverSse) {
+						const state = websocketState!;
 						const streamError = error instanceof Error ? error : new Error(String(error));
+						const replayingBufferedOutputOverSse = output.content.length > 0;
 						const isFatal = isCodexWebSocketFatalError(streamError);
-						const activateFallback = isFatal || websocketStreamRetries >= getCodexWebSocketRetryBudget();
-						recordCodexWebSocketFailure(websocketState, activateFallback);
+						const activateFallback =
+							replayingBufferedOutputOverSse ||
+							isFatal ||
+							websocketStreamRetries >= getCodexWebSocketRetryBudget();
+						recordCodexWebSocketFailure(state, activateFallback);
 						logCodexDebug("codex websocket stream fallback", {
 							error: streamError.message,
 							retry: websocketStreamRetries,
 							retryBudget: getCodexWebSocketRetryBudget(),
 							activated: activateFallback,
 							fatal: isFatal,
+							replayedBufferedOutput: replayingBufferedOutputOverSse,
 						});
 						if (!activateFallback) {
 							websocketStreamRetries += 1;
 							await abortableSleep(getCodexWebSocketRetryDelayMs(websocketStreamRetries), options?.signal);
-							const websocketRequest = buildCodexWebSocketRequest(transformedBody, websocketState);
+							const websocketRequest = buildCodexWebSocketRequest(transformedBody, state);
 							const websocketHeaders = createCodexHeaders(
 								requestHeaders,
 								accountId,
 								apiKey,
 								options?.sessionId,
 								"websocket",
-								websocketState,
+								state,
 							);
 							requestBodyForState = cloneRequestBody(transformedBody);
 							eventStream = await openCodexWebSocketEventStream(
 								toWebSocketUrl(url),
 								websocketHeaders,
 								websocketRequest,
-								websocketState,
+								state,
 								options?.signal,
 							);
 							usingWebsocket = true;
-							websocketState.lastTransport = "websocket";
+							state.lastTransport = "websocket";
 							continue;
 						}
+						if (replayingBufferedOutputOverSse) {
+							canSafelyReplayWebsocketOverSse = true;
+							currentItem = null;
+							currentBlock = null;
+							output.content.length = 0;
+							nativeOutputItems.length = 0;
+							output.usage = {
+								input: 0,
+								output: 0,
+								cacheRead: 0,
+								cacheWrite: 0,
+								totalTokens: 0,
+								cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+							};
+							output.stopReason = "stop";
+							firstTokenTime = undefined;
+						}
 						eventStream = await openCodexSseEventStream(
 							url,
 							requestHeaders,
@@ -778,11 +804,11 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 							apiKey,
 							options?.sessionId,
 							transformedBody,
-							websocketState,
+							state,
 							options?.signal,
 						);
 						usingWebsocket = false;
-						websocketState.lastTransport = "sse";
+						state.lastTransport = "sse";
 						requestBodyForState = cloneRequestBody(transformedBody);
 						continue;
 					}

packages/coding-agent/src/prompts/system/handoff-document.md

@@ -43,4 +43,4 @@ Use exactly this structure:
 <instruction>
 Additional focus: {{additionalFocus}}
 </instruction>
-{{/if}}
+{{/if}}

packages/coding-agent/src/web/scrapers/docs-rs.ts

@@ -500,7 +500,6 @@ function collectExplicitTraitImplNames(implIds: number[], index: Record<string,
 	return names;
 }
 
-
 function renderSingleItem(item: RustdocItem, index: Record<string, RustdocItem>, crate_: RustdocCrate): string {
 	let md = "";
 	const decl = renderItemDecl(item);
@@ -545,18 +544,14 @@ function renderSingleItem(item: RustdocItem, index: Record<string, RustdocItem>,
 		}
 
 		const methods = collectInherentMethodLines(impls, index);
-		if (methods.length) md += `## Methods
-
-${methods.join("\n")}
-
-`;
+		if (methods.length) {
+			md += `## Methods\n\n${methods.join("\n")}\n\n`;
+		}
 
 		const traitImpls = collectExplicitTraitImplNames(impls, index);
-		if (traitImpls.length) md += `## Trait Implementations
-
-${traitImpls.map(t => `- ${t}`).join("\n")}
-
-`;
+		if (traitImpls.length) {
+			md += `## Trait Implementations\n\n${traitImpls.map(t => `- ${t}`).join("\n")}\n\n`;
+		}
 	}
 
 	// For enums, show variants