feat: add reasoning_effort configuration support for Doubao/GPT-5 models (#947)

* feat: Add reasoning effort configuration support

* Add `reasoning_effort` parameter to model config and agent initialization
* Support reasoning effort levels (minimal/low/medium/high) for Doubao/GPT-5 models
* Add UI controls in input box for reasoning effort selection
* Update doubao-seed-1.8 example config with reasoning effort support

Fixes & Cleanup:
* Ensure UTF-8 encoding for file operations
* Remove unused imports

* fix: set reasoning_effort to None for unsupported models

* fix: unit test error

* Update frontend/src/components/workspace/input-box.tsx

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

frontend/src/app/workspace/chats/[thread_id]/page.tsx

@@ -177,6 +177,7 @@ export default function ChatPage() {
       is_plan_mode:
         settings.context.mode === "pro" || settings.context.mode === "ultra",
       subagent_enabled: settings.context.mode === "ultra",
+      reasoning_effort: settings.context.reasoning_effort,
     },
     afterSubmit() {
       router.push(pathOfThread(threadId!));
@@ -236,10 +237,9 @@ export default function ChatPage() {
                   className={cn("size-full", !isNewThread && "pt-10")}
                   threadId={threadId}
                   thread={thread}
-                  messagesOverride={
-                    !thread.isLoading && finalState?.messages
-                      ? (finalState.messages as Message[])
-                      : undefined
+                  messages={
+                    (finalState?.messages as Message[])
+                      ?? thread.messages
                   }
                   paddingBottom={todoListCollapsed ? 160 : 280}
                 />

frontend/src/components/workspace/input-box.tsx

@@ -106,6 +106,7 @@ export function InputBox({
     "thread_id" | "is_plan_mode" | "thinking_enabled" | "subagent_enabled"
   > & {
     mode: "flash" | "thinking" | "pro" | "ultra" | undefined;
+    reasoning_effort?: "minimal" | "low" | "medium" | "high";
   };
   extraHeader?: React.ReactNode;
   isNewThread?: boolean;
@@ -116,6 +117,7 @@ export function InputBox({
       "thread_id" | "is_plan_mode" | "thinking_enabled" | "subagent_enabled"
     > & {
       mode: "flash" | "thinking" | "pro" | "ultra" | undefined;
+      reasoning_effort?: "minimal" | "low" | "medium" | "high";
     },
   ) => void;
   onSubmit?: (message: PromptInputMessage) => void;
@@ -159,6 +161,11 @@ export function InputBox({
     [selectedModel],
   );
 
+  const supportReasoningEffort = useMemo(
+    () => selectedModel?.supports_reasoning_effort ?? false,
+    [selectedModel],
+  );
+
   const handleModelSelect = useCallback(
     (model_name: string) => {
       const model = models.find((m) => m.name === model_name);
@@ -169,6 +176,7 @@ export function InputBox({
         ...context,
         model_name,
         mode: getResolvedMode(context.mode, model.supports_thinking ?? false),
+        reasoning_effort: context.reasoning_effort,
       });
       setModelDialogOpen(false);
     },
@@ -180,10 +188,22 @@ export function InputBox({
       onContextChange?.({
         ...context,
         mode: getResolvedMode(mode, supportThinking),
+        reasoning_effort: mode === "ultra" ? "high" : mode === "pro" ? "medium" : mode === "thinking" ? "low" : "minimal",
       });
     },
     [onContextChange, context, supportThinking],
   );
+
+  const handleReasoningEffortSelect = useCallback(
+    (effort: "minimal" | "low" | "medium" | "high") => {
+      onContextChange?.({
+        ...context,
+        reasoning_effort: effort,
+      });
+    },
+    [onContextChange, context],
+  );
+
   const handleSubmit = useCallback(
     async (message: PromptInputMessage) => {
       if (status === "streaming") {
@@ -244,9 +264,9 @@ export function InputBox({
             <ModeHoverGuide
               mode={
                 context.mode === "flash" ||
-                context.mode === "thinking" ||
-                context.mode === "pro" ||
-                context.mode === "ultra"
+                  context.mode === "thinking" ||
+                  context.mode === "pro" ||
+                  context.mode === "ultra"
                   ? context.mode
                   : "flash"
               }
@@ -297,7 +317,7 @@ export function InputBox({
                           className={cn(
                             "mr-2 size-4",
                             context.mode === "flash" &&
-                              "text-accent-foreground",
+                            "text-accent-foreground",
                           )}
                         />
                         {t.inputBox.flashMode}
@@ -327,7 +347,7 @@ export function InputBox({
                             className={cn(
                               "mr-2 size-4",
                               context.mode === "thinking" &&
-                                "text-accent-foreground",
+                              "text-accent-foreground",
                             )}
                           />
                           {t.inputBox.reasoningMode}
@@ -409,6 +429,116 @@ export function InputBox({
               </DropdownMenuGroup>
             </PromptInputActionMenuContent>
           </PromptInputActionMenu>
+          {supportReasoningEffort && context.mode !== "flash" && (
+            <PromptInputActionMenu>
+              <PromptInputActionMenuTrigger className="gap-1! px-2!">
+                <div className="text-xs font-normal">
+                  {t.inputBox.reasoningEffort}:
+                  {context.reasoning_effort === "minimal" && " " + t.inputBox.reasoningEffortMinimal}
+                  {context.reasoning_effort === "low" && " " + t.inputBox.reasoningEffortLow}
+                  {context.reasoning_effort === "medium" && " " + t.inputBox.reasoningEffortMedium}
+                  {context.reasoning_effort === "high" && " " + t.inputBox.reasoningEffortHigh}
+                </div>
+              </PromptInputActionMenuTrigger>
+              <PromptInputActionMenuContent className="w-70">
+                <DropdownMenuGroup>
+                  <DropdownMenuLabel className="text-muted-foreground text-xs">
+                    {t.inputBox.reasoningEffort}
+                  </DropdownMenuLabel>
+                  <PromptInputActionMenu>
+                    <PromptInputActionMenuItem
+                      className={cn(
+                        context.reasoning_effort === "minimal"
+                          ? "text-accent-foreground"
+                          : "text-muted-foreground/65",
+                      )}
+                      onSelect={() => handleReasoningEffortSelect("minimal")}
+                    >
+                      <div className="flex flex-col gap-2">
+                        <div className="flex items-center gap-1 font-bold">
+                          {t.inputBox.reasoningEffortMinimal}
+                        </div>
+                        <div className="pl-2 text-xs">
+                          {t.inputBox.reasoningEffortMinimalDescription}
+                        </div>
+                      </div>
+                      {context.reasoning_effort === "minimal" ? (
+                        <CheckIcon className="ml-auto size-4" />
+                      ) : (
+                        <div className="ml-auto size-4" />
+                      )}
+                    </PromptInputActionMenuItem>
+                    <PromptInputActionMenuItem
+                      className={cn(
+                        context.reasoning_effort === "low"
+                          ? "text-accent-foreground"
+                          : "text-muted-foreground/65",
+                      )}
+                      onSelect={() => handleReasoningEffortSelect("low")}
+                    >
+                      <div className="flex flex-col gap-2">
+                        <div className="flex items-center gap-1 font-bold">
+                          {t.inputBox.reasoningEffortLow}
+                        </div>
+                        <div className="pl-2 text-xs">
+                          {t.inputBox.reasoningEffortLowDescription}
+                        </div>
+                      </div>
+                      {context.reasoning_effort === "low" ? (
+                        <CheckIcon className="ml-auto size-4" />
+                      ) : (
+                        <div className="ml-auto size-4" />
+                      )}
+                    </PromptInputActionMenuItem>
+                    <PromptInputActionMenuItem
+                      className={cn(
+                        context.reasoning_effort === "medium" || !context.reasoning_effort
+                          ? "text-accent-foreground"
+                          : "text-muted-foreground/65",
+                      )}
+                      onSelect={() => handleReasoningEffortSelect("medium")}
+                    >
+                      <div className="flex flex-col gap-2">
+                        <div className="flex items-center gap-1 font-bold">
+                          {t.inputBox.reasoningEffortMedium}
+                        </div>
+                        <div className="pl-2 text-xs">
+                          {t.inputBox.reasoningEffortMediumDescription}
+                        </div>
+                      </div>
+                      {context.reasoning_effort === "medium" || !context.reasoning_effort ? (
+                        <CheckIcon className="ml-auto size-4" />
+                      ) : (
+                        <div className="ml-auto size-4" />
+                      )}
+                    </PromptInputActionMenuItem>
+                    <PromptInputActionMenuItem
+                      className={cn(
+                        context.reasoning_effort === "high"
+                          ? "text-accent-foreground"
+                          : "text-muted-foreground/65",
+                      )}
+                      onSelect={() => handleReasoningEffortSelect("high")}
+                    >
+                      <div className="flex flex-col gap-2">
+                        <div className="flex items-center gap-1 font-bold">
+                          {t.inputBox.reasoningEffortHigh}
+                        </div>
+                        <div className="pl-2 text-xs">
+                          {t.inputBox.reasoningEffortHighDescription}
+                        </div>
+                      </div>
+                      {context.reasoning_effort === "high" ? (
+                        <CheckIcon className="ml-auto size-4" />
+                      ) : (
+                        <div className="ml-auto size-4" />
+                      )}
+                    </PromptInputActionMenuItem>
+                  </PromptInputActionMenu>
+                </DropdownMenuGroup>
+              </PromptInputActionMenuContent>
+            </PromptInputActionMenu>
+          )}
         </PromptInputTools>
         <PromptInputTools>
           <ModelSelector

frontend/src/components/workspace/messages/message-list.tsx

@@ -34,20 +34,18 @@ export function MessageList({
   className,
   threadId,
   thread,
-  messagesOverride,
+  messages,
   paddingBottom = 160,
 }: {
   className?: string;
   threadId: string;
   thread: UseStream<AgentThreadState>;
-  /** When set (e.g. from onFinish), use instead of thread.messages so SSE end shows complete state. */
-  messagesOverride?: Message[];
+  messages: Message[];
   paddingBottom?: number;
 }) {
   const { t } = useI18n();
   const rehypePlugins = useRehypeSplitWordsIntoSpans(thread.isLoading);
   const updateSubtask = useUpdateSubtask();
-  const messages = messagesOverride ?? thread.messages;
   if (thread.isThreadLoading) {
     return <MessageListSkeleton />;
   }

frontend/src/core/i18n/locales/en-US.ts

@@ -82,6 +82,15 @@ export const enUS: Translations = {
     ultraMode: "Ultra",
     ultraModeDescription:
       "Pro mode with subagents to divide work; best for complex multi-step tasks",
+    reasoningEffort: "Reasoning Effort",
+    reasoningEffortMinimal: "Minimal",
+    reasoningEffortMinimalDescription: "Retrieval + Direct Output",
+    reasoningEffortLow: "Low",
+    reasoningEffortLowDescription: "Simple Logic Check + Shallow Deduction",
+    reasoningEffortMedium: "Medium",
+    reasoningEffortMediumDescription: "Multi-layer Logic Analysis + Basic Verification",
+    reasoningEffortHigh: "High",
+    reasoningEffortHighDescription: "Full-dimensional Logic Deduction + Multi-path Verification + Backward Check",
     searchModels: "Search models...",
     surpriseMe: "Surprise",
     surpriseMePrompt: "Surprise me",

frontend/src/core/i18n/locales/types.ts

@@ -64,6 +64,15 @@ export interface Translations {
     proModeDescription: string;
     ultraMode: string;
     ultraModeDescription: string;
+    reasoningEffort: string;
+    reasoningEffortMinimal: string;
+    reasoningEffortMinimalDescription: string;
+    reasoningEffortLow: string;
+    reasoningEffortLowDescription: string;
+    reasoningEffortMedium: string;
+    reasoningEffortMediumDescription: string;
+    reasoningEffortHigh: string;
+    reasoningEffortHighDescription: string;
     searchModels: string;
     surpriseMe: string;
     surpriseMePrompt: string;

frontend/src/core/i18n/locales/zh-CN.ts

@@ -80,6 +80,15 @@ export const zhCN: Translations = {
     ultraMode: "Ultra",
     ultraModeDescription:
       "继承自 Pro 模式，可调用子代理分工协作，适合复杂多步骤任务，能力最强",
+    reasoningEffort: "推理深度",
+    reasoningEffortMinimal: "最低",
+    reasoningEffortMinimalDescription: "检索 + 直接输出",
+    reasoningEffortLow: "低",
+    reasoningEffortLowDescription: "简单逻辑校验 + 浅层推演",
+    reasoningEffortMedium: "中",
+    reasoningEffortMediumDescription: "多层逻辑分析 + 基础验证",
+    reasoningEffortHigh: "高",
+    reasoningEffortHighDescription: "全维度逻辑推演 + 多路径验证 + 反推校验",
     searchModels: "搜索模型...",
     surpriseMe: "小惊喜",
     surpriseMePrompt: "给我一个小惊喜吧",

frontend/src/core/models/types.ts

@@ -4,4 +4,5 @@ export interface Model {
   display_name: string;
   description?: string | null;
   supports_thinking?: boolean;
+  supports_reasoning_effort?: boolean;
 }

frontend/src/core/settings/local.ts

@@ -7,6 +7,7 @@ export const DEFAULT_LOCAL_SETTINGS: LocalSettings = {
   context: {
     model_name: undefined,
     mode: undefined,
+    reasoning_effort: undefined,
   },
   layout: {
     sidebar_collapsed: false,
@@ -24,6 +25,7 @@ export interface LocalSettings {
     "thread_id" | "is_plan_mode" | "thinking_enabled" | "subagent_enabled"
   > & {
     mode: "flash" | "thinking" | "pro" | "ultra" | undefined;
+    reasoning_effort?: "minimal" | "low" | "medium" | "high";
   };
   layout: {
     sidebar_collapsed: boolean;

frontend/src/core/threads/types.ts

@@ -18,4 +18,5 @@ export interface AgentThreadContext extends Record<string, unknown> {
   thinking_enabled: boolean;
   is_plan_mode: boolean;
   subagent_enabled: boolean;
+  reasoning_effort?: "minimal" | "low" | "medium" | "high";
 }