fix(openai): omit temperature for models that don't support it (#215)

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

@@ -391,6 +391,33 @@ describe("OpenAiHandler", () => {
 			expect(callArgs.reasoning_effort).toBeUndefined()
 		})
 
+		it("should omit temperature when the model sets supportsTemperature to false", async () => {
+			const noTempOptions: ApiHandlerOptions = {
+				...mockOptions,
+				openAiCustomModelInfo: {
+					contextWindow: 128_000,
+					supportsPromptCache: false,
+					supportsTemperature: false,
+				},
+			}
+			const noTempHandler = new OpenAiHandler(noTempOptions)
+			const stream = noTempHandler.createMessage(systemPrompt, messages)
+			for await (const _chunk of stream) {
+			}
+			expect(mockCreate).toHaveBeenCalled()
+			const callArgs = mockCreate.mock.calls[0][0]
+			expect(callArgs).not.toHaveProperty("temperature")
+		})
+
+		it("should include temperature by default when supportsTemperature is not set", async () => {
+			const stream = handler.createMessage(systemPrompt, messages)
+			for await (const _chunk of stream) {
+			}
+			expect(mockCreate).toHaveBeenCalled()
+			const callArgs = mockCreate.mock.calls[0][0]
+			expect(callArgs).toHaveProperty("temperature")
+		})
+
 		it("should include max_tokens when includeMaxTokens is true", async () => {
 			const optionsWithMaxTokens: ApiHandlerOptions = {
 				...mockOptions,

src/api/providers/openai.ts

@@ -154,7 +154,13 @@ export class OpenAiHandler extends BaseProvider implements SingleCompletionHandl
 
 			const requestOptions: OpenAI.Chat.Completions.ChatCompletionCreateParamsStreaming = {
 				model: modelId,
-				temperature: this.options.modelTemperature ?? (deepseekReasoner ? DEEP_SEEK_DEFAULT_TEMPERATURE : 0),
+				// Some OpenAI-Compatible models (e.g. claude-opus-4-7) reject `temperature` as
+				// deprecated/unsupported. Honor the model's `supportsTemperature` flag and omit it
+				// when explicitly set to false (undefined still sends temperature, preserving behavior).
+				...(modelInfo.supportsTemperature !== false && {
+					temperature:
+						this.options.modelTemperature ?? (deepseekReasoner ? DEEP_SEEK_DEFAULT_TEMPERATURE : 0),
+				}),
 				messages: convertedMessages,
 				stream: true as const,
 				...(isGrokXAI ? {} : { stream_options: { include_usage: true } }),