🤖 feat: add Fast/Slow service-tier control to chat input

src/browser/components/ServiceTierPicker/ServiceTierPicker.test.tsx

@@ -0,0 +1,114 @@
+import { afterEach, beforeEach, describe, expect, test } from "bun:test";
+import { cleanup, fireEvent, render, waitFor } from "@testing-library/react";
+import { installDom } from "../../../../tests/ui/dom";
+
+import { TooltipProvider } from "@/browser/components/Tooltip/Tooltip";
+import { getServiceTierKey } from "@/common/constants/storage";
+import { ServiceTierPicker } from "./ServiceTierPicker";
+
+const OPENAI_MODEL = "openai:gpt-5.5";
+const ANTHROPIC_MODEL = "anthropic:claude-haiku-4-5";
+const SCOPE = "ws-service-tier-test";
+
+let cleanupDom: (() => void) | null = null;
+
+function renderPicker(modelString: string) {
+  return render(
+    <TooltipProvider>
+      <ServiceTierPicker modelString={modelString} scopeId={SCOPE} />
+    </TooltipProvider>
+  );
+}
+
+describe("ServiceTierPicker", () => {
+  beforeEach(() => {
+    cleanupDom = installDom();
+    globalThis.window.localStorage.clear();
+  });
+
+  afterEach(() => {
+    cleanup();
+    cleanupDom?.();
+    cleanupDom = null;
+  });
+
+  test("renders nothing for models without service-tier support", () => {
+    const { queryByTestId } = renderPicker(ANTHROPIC_MODEL);
+    expect(queryByTestId("service-tier-trigger")).toBeNull();
+  });
+
+  test("shows the neutral (default) state for a supported model with no override", () => {
+    const { getByTestId } = renderPicker(OPENAI_MODEL);
+    const trigger = getByTestId("service-tier-trigger");
+    expect(trigger.getAttribute("data-service-tier")).toBe("default");
+  });
+
+  test("opens a menu and applies the Fast override", async () => {
+    const { getByTestId, queryByTestId, getAllByTestId } = renderPicker(OPENAI_MODEL);
+
+    // Menu is closed initially.
+    expect(queryByTestId("service-tier-option")).toBeNull();
+
+    fireEvent.click(getByTestId("service-tier-trigger"));
+
+    await waitFor(() => {
+      expect(getAllByTestId("service-tier-option").length).toBe(3);
+    });
+
+    const fast = getAllByTestId("service-tier-option").find(
+      (el) => el.getAttribute("data-speed") === "fast"
+    );
+    expect(fast).toBeTruthy();
+    fireEvent.click(fast!);
+
+    await waitFor(() => {
+      expect(getByTestId("service-tier-trigger").getAttribute("data-service-tier")).toBe("fast");
+    });
+
+    // Override is persisted under the scoped key as the provider wire value.
+    expect(globalThis.window.localStorage.getItem(getServiceTierKey(SCOPE))).toBe(
+      JSON.stringify("priority")
+    );
+    // Menu closes after selection.
+    expect(queryByTestId("service-tier-option")).toBeNull();
+  });
+
+  test("applies the Slow override", async () => {
+    const { getByTestId, getAllByTestId } = renderPicker(OPENAI_MODEL);
+    fireEvent.click(getByTestId("service-tier-trigger"));
+
+    await waitFor(() => expect(getAllByTestId("service-tier-option").length).toBe(3));
+    const slow = getAllByTestId("service-tier-option").find(
+      (el) => el.getAttribute("data-speed") === "slow"
+    );
+    fireEvent.click(slow!);
+
+    await waitFor(() => {
+      expect(getByTestId("service-tier-trigger").getAttribute("data-service-tier")).toBe("slow");
+    });
+    expect(globalThis.window.localStorage.getItem(getServiceTierKey(SCOPE))).toBe(
+      JSON.stringify("flex")
+    );
+  });
+
+  test("selecting Auto clears an existing override", async () => {
+    // Seed an existing Fast override.
+    globalThis.window.localStorage.setItem(getServiceTierKey(SCOPE), JSON.stringify("priority"));
+
+    const { getByTestId, getAllByTestId } = renderPicker(OPENAI_MODEL);
+    expect(getByTestId("service-tier-trigger").getAttribute("data-service-tier")).toBe("fast");
+
+    fireEvent.click(getByTestId("service-tier-trigger"));
+    await waitFor(() => expect(getAllByTestId("service-tier-option").length).toBe(3));
+    const auto = getAllByTestId("service-tier-option").find(
+      (el) => el.getAttribute("data-speed") === "default"
+    );
+    fireEvent.click(auto!);
+
+    await waitFor(() => {
+      expect(getByTestId("service-tier-trigger").getAttribute("data-service-tier")).toBe("default");
+    });
+    // Auto clears the override entirely (key removed), so the provider/global default applies.
+    expect(globalThis.window.localStorage.getItem(getServiceTierKey(SCOPE))).toBeNull();
+  });
+});

src/browser/components/ServiceTierPicker/ServiceTierPicker.tsx

@@ -0,0 +1,225 @@
+import React, { useCallback, useEffect, useRef, useState } from "react";
+import { Check, Zap } from "lucide-react";
+
+import { cn } from "@/common/lib/utils";
+import { type ServiceTier } from "@/common/config/schemas/providersConfig";
+import {
+  getServiceTierSpeed,
+  SERVICE_TIER_FAST,
+  SERVICE_TIER_SLOW,
+  supportsServiceTier,
+  type ServiceTierSpeed,
+} from "@/common/utils/ai/serviceTier";
+import { useServiceTier } from "@/browser/hooks/useServiceTier";
+import { Tooltip, TooltipContent, TooltipTrigger } from "../Tooltip/Tooltip";
+import { stopKeyboardPropagation } from "@/browser/utils/events";
+
+interface ServiceTierPickerProps {
+  /** Canonical model string used to gate visibility (only shown for supporting models). */
+  modelString: string;
+  /** Workspace id (workspace view) or project scope id (creation view). */
+  scopeId: string;
+  className?: string;
+}
+
+interface ServiceTierOption {
+  speed: ServiceTierSpeed;
+  /** null clears the override (falls back to the provider/global default). */
+  tier: ServiceTier | null;
+  label: string;
+  description: string;
+}
+
+// "Fast"/"Slow"/"Auto" wording keeps the control provider-agnostic even though
+// only OpenAI honors service_tier today.
+const OPTIONS: readonly ServiceTierOption[] = [
+  { speed: "default", tier: null, label: "Auto", description: "Provider default speed" },
+  {
+    speed: "fast",
+    tier: SERVICE_TIER_FAST,
+    label: "Fast",
+    description: "Prioritize low latency (higher cost)",
+  },
+  {
+    speed: "slow",
+    tier: SERVICE_TIER_SLOW,
+    label: "Slow",
+    description: "Prioritize lower cost (higher latency)",
+  },
+];
+
+/** CSS variable for the active speed, or undefined for the neutral (grey) state. */
+function getSpeedColorVar(speed: ServiceTierSpeed): string | undefined {
+  if (speed === "fast") return "var(--color-service-tier-fast)";
+  if (speed === "slow") return "var(--color-service-tier-slow)";
+  return undefined;
+}
+
+/**
+ * Lightning-bolt control for the chat-specific service-tier (speed) override.
+ *
+ * - Fast → bolt glows orange, Slow → bolt turns blue, Auto/default → neutral grey.
+ * - Clicking opens a small keyboard-navigable menu that sets the per-chat override.
+ *
+ * Rendered only for models that support service tiers (OpenAI/GPT today). Uses
+ * conditional rendering (not a Radix portal) so it stays testable under happy-dom.
+ */
+export const ServiceTierPicker: React.FC<ServiceTierPickerProps> = (props) => {
+  const [serviceTier, setServiceTier] = useServiceTier(props.scopeId);
+  const [isOpen, setIsOpen] = useState(false);
+  const [highlightedIndex, setHighlightedIndex] = useState(-1);
+
+  const containerRef = useRef<HTMLDivElement>(null);
+  const dropdownRef = useRef<HTMLDivElement>(null);
+
+  const currentSpeed = getServiceTierSpeed(serviceTier);
+
+  const closePicker = useCallback(() => {
+    setIsOpen(false);
+    setHighlightedIndex(-1);
+  }, []);
+
+  const openPicker = useCallback(() => {
+    setIsOpen(true);
+    const currentIndex = OPTIONS.findIndex((opt) => opt.speed === currentSpeed);
+    setHighlightedIndex(currentIndex >= 0 ? currentIndex : 0);
+    requestAnimationFrame(() => dropdownRef.current?.focus());
+  }, [currentSpeed]);
+
+  const handleSelect = useCallback(
+    (option: ServiceTierOption) => {
+      setServiceTier(option.tier);
+      closePicker();
+    },
+    [closePicker, setServiceTier]
+  );
+
+  // Close when clicking outside the control.
+  useEffect(() => {
+    if (!isOpen) {
+      return;
+    }
+    const handleClickOutside = (e: MouseEvent) => {
+      if (containerRef.current?.contains(e.target as Node)) {
+        return;
+      }
+      closePicker();
+    };
+    document.addEventListener("mousedown", handleClickOutside);
+    return () => document.removeEventListener("mousedown", handleClickOutside);
+  }, [closePicker, isOpen]);
+
+  const handleDropdownKeyDown = (e: React.KeyboardEvent<HTMLDivElement>) => {
+    if (e.key === "Escape") {
+      e.preventDefault();
+      stopKeyboardPropagation(e);
+      closePicker();
+      return;
+    }
+    if (e.key === "Enter") {
+      e.preventDefault();
+      const option = OPTIONS[highlightedIndex >= 0 ? highlightedIndex : 0];
+      if (option) {
+        handleSelect(option);
+      }
+      return;
+    }
+    if (e.key === "ArrowDown") {
+      e.preventDefault();
+      setHighlightedIndex((prev) => Math.min(prev + 1, OPTIONS.length - 1));
+      return;
+    }
+    if (e.key === "ArrowUp") {
+      e.preventDefault();
+      setHighlightedIndex((prev) => Math.max(prev - 1, 0));
+      return;
+    }
+  };
+
+  // Only models that honor service tiers expose this affordance.
+  if (!supportsServiceTier(props.modelString)) {
+    return null;
+  }
+
+  const activeColor = getSpeedColorVar(currentSpeed);
+  const activeLabel = OPTIONS.find((opt) => opt.speed === currentSpeed)?.label ?? "Auto";
+
+  return (
+    <div ref={containerRef} className={cn("relative flex items-center", props.className)}>
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <button
+            type="button"
+            onClick={() => (isOpen ? closePicker() : openPicker())}
+            data-testid="service-tier-trigger"
+            data-service-tier={currentSpeed}
+            aria-haspopup="menu"
+            aria-expanded={isOpen}
+            aria-label={`Service tier: ${activeLabel}. Click to change.`}
+            className={cn(
+              "flex h-4 w-4 items-center justify-center rounded-sm transition-colors",
+              activeColor ? "" : "text-muted hover:text-foreground hover:bg-hover"
+            )}
+            style={
+              activeColor
+                ? {
+                    color: activeColor,
+                    // Orange "glow" for Fast; a softer halo for Slow.
+                    filter: `drop-shadow(0 0 ${currentSpeed === "fast" ? "5px" : "3px"} ${activeColor})`,
+                  }
+                : undefined
+            }
+          >
+            <Zap className="h-3 w-3" />
+          </button>
+        </TooltipTrigger>
+        <TooltipContent align="center">
+          Service tier: <span className="font-medium">{activeLabel}</span>. Sets request speed for
+          this chat. Saved per workspace.
+        </TooltipContent>
+      </Tooltip>
+
+      {isOpen && (
+        <div
+          ref={dropdownRef}
+          tabIndex={-1}
+          role="menu"
+          onKeyDown={handleDropdownKeyDown}
+          className="bg-separator border-border-light absolute bottom-full left-0 z-[1020] mb-1 min-w-48 overflow-hidden rounded border shadow-[0_4px_12px_rgba(0,0,0,0.3)] outline-none"
+        >
+          <div className="py-1">
+            {OPTIONS.map((option, index) => {
+              const isHighlighted = index === highlightedIndex;
+              const isSelected = option.speed === currentSpeed;
+              const color = getSpeedColorVar(option.speed);
+              return (
+                <div
+                  key={option.speed}
+                  role="menuitemradio"
+                  aria-checked={isSelected}
+                  tabIndex={-1}
+                  data-testid="service-tier-option"
+                  data-speed={option.speed}
+                  className={cn(
+                    "flex cursor-pointer items-center gap-2.5 px-2.5 py-1.5 transition-colors duration-100",
+                    isHighlighted ? "bg-hover text-foreground" : "bg-transparent hover:bg-hover",
+                    isSelected ? "text-foreground" : "text-light hover:text-foreground"
+                  )}
+                  onMouseEnter={() => setHighlightedIndex(index)}
+                  onClick={() => handleSelect(option)}
+                >
+                  <Zap className="h-3.5 w-3.5 shrink-0" style={color ? { color } : undefined} />
+                  <div className="min-w-0 flex-1">
+                    <div className="text-[11px] font-medium">{option.label}</div>
+                    <div className="text-muted-light text-[10px]">{option.description}</div>
+                  </div>
+                  {isSelected && <Check className="text-accent h-3.5 w-3.5 shrink-0" />}
+                </div>
+              );
+            })}
+          </div>
+        </div>
+      )}
+    </div>
+  );
+};

src/browser/features/ChatInput/index.tsx

@@ -31,6 +31,7 @@ import { useWorkspaceContext } from "@/browser/contexts/WorkspaceContext";
 import { useProjectContext } from "@/browser/contexts/ProjectContext";
 import { useAgent } from "@/browser/contexts/AgentContext";
 import { ThinkingSliderComponent } from "@/browser/components/ThinkingSlider/ThinkingSlider";
+import { ServiceTierPicker } from "@/browser/components/ServiceTierPicker/ServiceTierPicker";
 import {
   getAllowedRuntimeModesForUi,
   isParsedRuntimeAllowedByPolicy,
@@ -713,10 +714,11 @@ const ChatInputInner: React.FC<ChatInputProps> = (props) => {
   }, [variant, startTutorial]);
 
   // Get current send message options from shared hook (must be at component top level)
-  // For creation variant, use project-scoped key; for workspace, use workspace ID
-  const sendMessageOptions = useSendMessageOptions(
-    variant === "workspace" ? props.workspaceId : getProjectScopeId(creationParentProjectPath)
-  );
+  // For creation variant, use project-scoped key; for workspace, use workspace ID.
+  // Shared so the service-tier override and send options resolve the same scope.
+  const sendOptionsScopeId =
+    variant === "workspace" ? props.workspaceId : getProjectScopeId(creationParentProjectPath);
+  const sendMessageOptions = useSendMessageOptions(sendOptionsScopeId);
   const additionalSystemContext = useAdditionalSystemContextSnapshot(
     variant === "workspace" ? props.workspaceId : ""
   );
@@ -3212,6 +3214,11 @@ const ChatInputInner: React.FC<ChatInputProps> = (props) => {
                 >
                   <ThinkingSliderComponent modelString={baseModel} />
                 </div>
+
+                {/* Service-tier (Fast/Slow) speed override. Renders its own root only for
+                    models that support service tiers (OpenAI/GPT today); otherwise it returns
+                    null and occupies no layout space (no stray flex gap). */}
+                <ServiceTierPicker modelString={baseModel} scopeId={sendOptionsScopeId} />
               </div>
 
               <div