fix: handle empty responses from Chutes AI API

- Add content tracking in ChutesHandler.createMessage() for both DeepSeek and non-DeepSeek models
- Throw descriptive error when API returns no content
- Add test coverage for empty response scenarios
- Fixes #7322

src/api/providers/__tests__/chutes.spec.ts

@@ -341,7 +341,10 @@ describe("ChutesHandler", () => {
 		mockCreate.mockClear()
 		mockCreate.mockImplementationOnce(async () => ({
 			[Symbol.asyncIterator]: async function* () {
-				// Empty stream for this test
+				// Yield minimal content to avoid triggering the empty response error
+				yield {
+					choices: [{ delta: { content: "test" } }],
+				}
 			},
 		}))
 
@@ -376,11 +379,22 @@ describe("ChutesHandler", () => {
 
 		mockCreate.mockImplementationOnce(() => {
 			return {
-				[Symbol.asyncIterator]: () => ({
-					async next() {
-						return { done: true }
-					},
-				}),
+				[Symbol.asyncIterator]: () => {
+					let called = false
+					return {
+						async next() {
+							if (!called) {
+								called = true
+								// Return minimal content to avoid triggering the empty response error
+								return {
+									done: false,
+									value: { choices: [{ delta: { content: "test" } }] },
+								}
+							}
+							return { done: true }
+						},
+					}
+				},
 			}
 		})
 
@@ -421,4 +435,86 @@ describe("ChutesHandler", () => {
 		const model = handlerWithModel.getModel()
 		expect(model.info.temperature).toBe(0.5)
 	})
+
+	it("should throw an error when API returns no content", async () => {
+		// Mock a stream that returns no content chunks
+		const mockStream = {
+			async *[Symbol.asyncIterator]() {
+				// Only yield usage data, no content
+				yield {
+					choices: [{ delta: {} }],
+					usage: {
+						prompt_tokens: 100,
+						completion_tokens: 0,
+					},
+				}
+			},
+		}
+
+		mockCreate.mockResolvedValueOnce(mockStream)
+
+		const systemPrompt = "Test system prompt"
+		const messages: Anthropic.Messages.MessageParam[] = [{ role: "user", content: "Test message" }]
+
+		const generator = handler.createMessage(systemPrompt, messages)
+		const chunks: any[] = []
+
+		await expect(async () => {
+			for await (const chunk of generator) {
+				chunks.push(chunk)
+			}
+		}).rejects.toThrow("Chutes API did not return any content")
+
+		// Should have yielded usage before throwing
+		expect(chunks).toHaveLength(1)
+		expect(chunks[0]).toEqual({
+			type: "usage",
+			inputTokens: 100,
+			outputTokens: 0,
+		})
+	})
+
+	it("should throw an error for DeepSeek R1 models when API returns no content", async () => {
+		const modelId: ChutesModelId = "deepseek-ai/DeepSeek-R1"
+		const handlerWithModel = new ChutesHandler({
+			apiModelId: modelId,
+			chutesApiKey: "test-chutes-api-key",
+		})
+
+		// Mock a stream that returns no content chunks
+		const mockStream = {
+			async *[Symbol.asyncIterator]() {
+				// Only yield usage data, no content
+				yield {
+					choices: [{ delta: {} }],
+					usage: {
+						prompt_tokens: 100,
+						completion_tokens: 0,
+					},
+				}
+			},
+		}
+
+		mockCreate.mockResolvedValueOnce(mockStream)
+
+		const systemPrompt = "Test system prompt"
+		const messages: Anthropic.Messages.MessageParam[] = [{ role: "user", content: "Test message" }]
+
+		const generator = handlerWithModel.createMessage(systemPrompt, messages)
+		const chunks: any[] = []
+
+		await expect(async () => {
+			for await (const chunk of generator) {
+				chunks.push(chunk)
+			}
+		}).rejects.toThrow("Chutes API did not return any content")
+
+		// Should have yielded usage before throwing
+		expect(chunks).toHaveLength(1)
+		expect(chunks[0]).toEqual({
+			type: "usage",
+			inputTokens: 100,
+			outputTokens: 0,
+		})
+	})
 })

src/api/providers/chutes.ts

@@ -46,6 +46,7 @@ export class ChutesHandler extends BaseOpenAiCompatibleProvider<ChutesModelId> {
 
 	override async *createMessage(systemPrompt: string, messages: Anthropic.Messages.MessageParam[]): ApiStream {
 		const model = this.getModel()
+		let hasContent = false
 
 		if (model.id.includes("DeepSeek-R1")) {
 			const stream = await this.client.chat.completions.create({
@@ -66,6 +67,7 @@ export class ChutesHandler extends BaseOpenAiCompatibleProvider<ChutesModelId> {
 				const delta = chunk.choices[0]?.delta
 
 				if (delta?.content) {
+					hasContent = true
 					for (const processedChunk of matcher.update(delta.content)) {
 						yield processedChunk
 					}
@@ -82,10 +84,46 @@ export class ChutesHandler extends BaseOpenAiCompatibleProvider<ChutesModelId> {
 
 			// Process any remaining content
 			for (const processedChunk of matcher.final()) {
+				hasContent = true
 				yield processedChunk
 			}
+
+			// If no content was received, throw an error
+			if (!hasContent) {
+				throw new Error(
+					`${this.providerName} API did not return any content. This may indicate an issue with the API, model configuration, or request parameters.`,
+				)
+			}
 		} else {
-			yield* super.createMessage(systemPrompt, messages)
+			// For non-DeepSeek models, track content and handle empty responses
+			const stream = await this.createStream(systemPrompt, messages)
+
+			for await (const chunk of stream) {
+				const delta = chunk.choices[0]?.delta
+
+				if (delta?.content) {
+					hasContent = true
+					yield {
+						type: "text",
+						text: delta.content,
+					}
+				}
+
+				if (chunk.usage) {
+					yield {
+						type: "usage",
+						inputTokens: chunk.usage.prompt_tokens || 0,
+						outputTokens: chunk.usage.completion_tokens || 0,
+					}
+				}
+			}
+
+			// If no content was received, throw an error
+			if (!hasContent) {
+				throw new Error(
+					`${this.providerName} API did not return any content. This may indicate an issue with the API, model configuration, or request parameters.`,
+				)
+			}
 		}
 	}