fix(aichat): fallback to completion if responses fails (#7190)

* fallback to completion if responses fails

* add missing fallbacks

* remove test errors

frontend/src/lib/components/copilot/chat/AIChatManager.svelte.ts

@@ -408,24 +408,42 @@ class AIChatManager {
 				}
 
 				const model = getCurrentModel()
-				const completionFn =
-					model.provider === 'anthropic'
-						? getAnthropicCompletion
-						: model.provider === 'openai' || model.provider === 'azure_openai'
-							? getOpenAIResponsesCompletion
-							: getCompletion
-				const parseFn =
-					model.provider === 'anthropic'
-						? parseAnthropicCompletion
-						: model.provider === 'openai' || model.provider === 'azure_openai'
-							? parseOpenAIResponsesCompletion
-							: parseOpenAICompletion
+				const isOpenAI = model.provider === 'openai' || model.provider === 'azure_openai'
+				const isAnthropic = model.provider === 'anthropic'
 
-				const completion = await completionFn(
-					[systemMessage, ...messages, ...(pendingUserMessage ? [pendingUserMessage] : [])],
-					abortController,
-					tools.map((t) => t.def)
-				)
+				let completion: any
+				let parseFn: any
+
+				const messageParams = [
+					systemMessage,
+					...messages,
+					...(pendingUserMessage ? [pendingUserMessage] : [])
+				]
+				const toolDefs = tools.map((t) => t.def)
+
+				// For OpenAI/Azure, try Responses API first, fallback to Completions API
+				if (isOpenAI) {
+					try {
+						completion = await getOpenAIResponsesCompletion(
+							messageParams,
+							abortController,
+							toolDefs
+						)
+						parseFn = parseOpenAIResponsesCompletion
+					} catch (err) {
+						console.warn('OpenAI Responses API failed, falling back to Completions API:', err)
+						completion = await getCompletion(messageParams, abortController, toolDefs, {
+							forceCompletions: true
+						})
+						parseFn = parseOpenAICompletion
+					}
+				} else if (isAnthropic) {
+					completion = await getAnthropicCompletion(messageParams, abortController, toolDefs)
+					parseFn = parseAnthropicCompletion
+				} else {
+					completion = await getCompletion(messageParams, abortController, toolDefs)
+					parseFn = parseOpenAICompletion
+				}
 
 				if (completion) {
 					const continueCompletion = await parseFn(

frontend/src/lib/components/copilot/lib.ts

@@ -675,7 +675,16 @@ export async function getNonStreamingCompletion(
 
 	// Use Responses API for OpenAI and Azure OpenAI
 	if (provider === 'openai' || provider === 'azure_openai') {
-		return getNonStreamingOpenAIResponsesCompletion(messages, abortController, testOptions)
+		try {
+			const response = await getNonStreamingOpenAIResponsesCompletion(
+				messages,
+				abortController,
+				testOptions
+			)
+			return response
+		} catch (error) {
+			console.error('Error using Responses API:', error)
+		}
 	}
 
 	const fetchOptions: {
@@ -793,13 +802,21 @@ export async function getFimCompletion(
 export async function getCompletion(
 	messages: ChatCompletionMessageParam[],
 	abortController: AbortController,
-	tools?: OpenAI.Chat.Completions.ChatCompletionTool[]
+	tools?: OpenAI.Chat.Completions.ChatCompletionTool[],
+	options?: {
+		forceCompletions?: boolean
+	}
 ): Promise<Stream<ChatCompletionChunk>> {
 	const { provider, config } = getProviderAndCompletionConfig({ messages, stream: true, tools })
 
 	// Use Responses API for OpenAI and Azure OpenAI
-	if (provider === 'openai' || provider === 'azure_openai') {
-		return getOpenAIResponsesCompletionStream(messages, abortController, tools) as any
+	if ((provider === 'openai' || provider === 'azure_openai') && !options?.forceCompletions) {
+		try {
+			const stream = getOpenAIResponsesCompletionStream(messages, abortController, tools) as any
+			return stream
+		} catch (error) {
+			console.error('Error using Responses API:', error)
+		}
 	}
 
 	// Use Completions API for other providers