feat(ui): add model thinking selector

packages/server/src/config/schema.ts

@@ -15,6 +15,7 @@ const PreferencesSchema = z.object({
   lastUsedBinary: z.string().optional(),
   environmentVariables: z.record(z.string()).default({}),
   modelRecents: z.array(ModelPreferenceSchema).default([]),
+  modelThinkingSelections: z.record(z.string(), z.string()).default({}),
   diffViewMode: z.enum(["split", "unified"]).default("split"),
   toolOutputExpansion: z.enum(["expanded", "collapsed"]).default("expanded"),
   diagnosticsExpansion: z.enum(["expanded", "collapsed"]).default("expanded"),

packages/ui/src/components/instance/instance-shell2.tsx

@@ -53,6 +53,7 @@ import InfoView from "../info-view"
 import InstanceServiceStatus from "../instance-service-status"
 import AgentSelector from "../agent-selector"
 import ModelSelector from "../model-selector"
+import ThinkingSelector from "../thinking-selector"
 import CommandPalette from "../command-palette"
 import PermissionNotificationBanner from "../permission-notification-banner"
 import PermissionApprovalModal from "../permission-approval-modal"
@@ -432,6 +433,14 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
     return true
   }
 
+  const focusVariantSelectorControl = () => {
+    const input = leftDrawerContentEl()?.querySelector<HTMLInputElement>("[data-thinking-selector]")
+    if (!input) return false
+    input.focus()
+    setTimeout(() => triggerKeyboardEvent(input, { key: "ArrowDown", code: "ArrowDown", keyCode: 40 }), 10)
+    return true
+  }
+
   createEffect(() => {
     const pending = pendingSidebarAction()
     if (!pending) return
@@ -444,7 +453,12 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
       setPendingSidebarAction(null)
       return
     }
-    const handled = action === "focus-agent-selector" ? focusAgentSelectorControl() : focusModelSelectorControl()
+    const handled =
+      action === "focus-agent-selector"
+        ? focusAgentSelectorControl()
+        : action === "focus-model-selector"
+          ? focusModelSelectorControl()
+          : focusVariantSelectorControl()
     if (handled) {
       setPendingSidebarAction(null)
     }
@@ -905,9 +919,12 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
                   <span class="hint sidebar-selector-hint sidebar-selector-hint--left">
                     <Kbd shortcut="cmd+shift+a" />
                   </span>
-                  <span class="hint sidebar-selector-hint sidebar-selector-hint--right">
+                  <span class="hint sidebar-selector-hint sidebar-selector-hint--center">
                     <Kbd shortcut="cmd+shift+m" />
                   </span>
+                  <span class="hint sidebar-selector-hint sidebar-selector-hint--right">
+                    <Kbd shortcut="cmd+shift+t" />
+                  </span>
                 </div>
 
                 <ModelSelector
@@ -916,6 +933,8 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
                   currentModel={activeSession().model}
                   onModelChange={(model) => props.handleSidebarModelChange(activeSession().id, model)}
                 />
+
+                <ThinkingSelector instanceId={props.instance.id} currentModel={activeSession().model} />
               </div>
             </>
           )}

packages/ui/src/components/thinking-selector.tsx

@@ -0,0 +1,103 @@
+import { Combobox } from "@kobalte/core/combobox"
+import { createEffect, createMemo } from "solid-js"
+import { providers, fetchProviders } from "../stores/sessions"
+import { ChevronDown } from "lucide-solid"
+import { getLogger } from "../lib/logger"
+import { getModelThinkingSelection, setModelThinkingSelection } from "../stores/preferences"
+
+const log = getLogger("session")
+
+interface ThinkingSelectorProps {
+  instanceId: string
+  currentModel: { providerId: string; modelId: string }
+}
+
+type ThinkingOption = {
+  key: string
+  label: string
+  value: string | undefined
+}
+
+export default function ThinkingSelector(props: ThinkingSelectorProps) {
+  const instanceProviders = () => providers().get(props.instanceId) || []
+
+  createEffect(() => {
+    if (instanceProviders().length === 0) {
+      fetchProviders(props.instanceId).catch((error) => log.error("Failed to fetch providers", error))
+    }
+  })
+
+  const variantKeys = createMemo(() => {
+    const { providerId, modelId } = props.currentModel
+    const provider = instanceProviders().find((p) => p.id === providerId)
+    const model = provider?.models.find((m) => m.id === modelId)
+    return model?.variantKeys ?? []
+  })
+
+  const options = createMemo<ThinkingOption[]>(() => {
+    const keys = variantKeys()
+    return [{ key: "__default__", label: "Default", value: undefined }, ...keys.map((k) => ({ key: k, label: k, value: k }))]
+  })
+
+  const currentValue = createMemo(() => {
+    const selected = getModelThinkingSelection(props.currentModel)
+    const keys = variantKeys()
+    if (selected && keys.includes(selected)) {
+      return options().find((opt) => opt.value === selected)
+    }
+    return options()[0]
+  })
+
+  const handleChange = (value: ThinkingOption | null) => {
+    if (!value) return
+    setModelThinkingSelection(props.currentModel, value.value)
+  }
+
+  const triggerPrimary = createMemo(() => {
+    const selected = currentValue()?.value
+    return selected ? `Thinking: ${selected}` : "Thinking: Default"
+  })
+
+  return (
+    <div class="sidebar-selector">
+      <Combobox<ThinkingOption>
+        value={currentValue()}
+        onChange={handleChange}
+        options={options()}
+        optionValue="key"
+        optionLabel="label"
+        placeholder="Thinking: Default"
+        itemComponent={(itemProps) => (
+          <Combobox.Item item={itemProps.item} class="selector-option">
+            <div class="selector-option-content">
+              <Combobox.ItemLabel class="selector-option-label">{itemProps.item.rawValue.label}</Combobox.ItemLabel>
+            </div>
+            <Combobox.ItemIndicator class="selector-option-indicator">
+              <svg class="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M5 13l4 4L19 7" />
+              </svg>
+            </Combobox.ItemIndicator>
+          </Combobox.Item>
+        )}
+      >
+        <Combobox.Control class="relative w-full" data-thinking-selector-control>
+          <Combobox.Input class="sr-only" data-thinking-selector />
+          <Combobox.Trigger class="selector-trigger">
+            <div class="selector-trigger-label selector-trigger-label--stacked">
+              <span class="selector-trigger-primary selector-trigger-primary--align-left">{triggerPrimary()}</span>
+            </div>
+            <Combobox.Icon class="selector-trigger-icon">
+              <ChevronDown class="w-3 h-3" />
+            </Combobox.Icon>
+          </Combobox.Trigger>
+        </Combobox.Control>
+
+        <Combobox.Portal>
+          <Combobox.Content class="selector-popover">
+            <Combobox.Listbox class="selector-listbox" />
+          </Combobox.Content>
+        </Combobox.Portal>
+      </Combobox>
+    </div>
+  )
+}

packages/ui/src/lib/hooks/use-app-lifecycle.ts

@@ -69,6 +69,11 @@ export function useAppLifecycle(options: UseAppLifecycleOptions) {
         if (!instance) return
         emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-agent-selector" })
       },
+      () => {
+        const instance = options.getActiveInstance()
+        if (!instance) return
+        emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-variant-selector" })
+      },
     )
 
     registerEscapeShortcut(

packages/ui/src/lib/hooks/use-commands.ts

@@ -374,6 +374,20 @@ export function useCommands(options: UseCommandsOptions) {
       },
     })
 
+    commandRegistry.register({
+      id: "open-variant-selector",
+      label: "Select Model Variant",
+      description: "Choose a thinking effort for the current model",
+      category: "Agent & Model",
+      keywords: ["variant", "thinking", "reasoning", "effort"],
+      shortcut: { key: "T", meta: true, shift: true },
+      action: () => {
+        const instance = activeInstance()
+        if (!instance) return
+        emitSessionSidebarRequest({ instanceId: instance.id, action: "focus-variant-selector" })
+      },
+    })
+
     commandRegistry.register({
       id: "open-agent-selector",
       label: "Open Agent Selector",

packages/ui/src/lib/session-sidebar-events.ts

@@ -1,4 +1,8 @@
-export type SessionSidebarRequestAction = "focus-agent-selector" | "focus-model-selector" | "show-session-list"
+export type SessionSidebarRequestAction =
+  | "focus-agent-selector"
+  | "focus-model-selector"
+  | "focus-variant-selector"
+  | "show-session-list"
 
 export interface SessionSidebarRequestDetail {
   instanceId: string

packages/ui/src/lib/shortcuts/agent.ts

@@ -1,6 +1,10 @@
 import { keyboardRegistry } from "../keyboard-registry"
 
-export function registerAgentShortcuts(focusModelSelector: () => void, openAgentSelector: () => void) {
+export function registerAgentShortcuts(
+  focusModelSelector: () => void,
+  openAgentSelector: () => void,
+  focusVariantSelector: () => void,
+) {
   const isMac = () => navigator.platform.toLowerCase().includes("mac")
 
   keyboardRegistry.register({
@@ -20,4 +24,13 @@ export function registerAgentShortcuts(focusModelSelector: () => void, openAgent
     description: "open agent",
     context: "global",
   })
+
+  keyboardRegistry.register({
+    id: "focus-variant",
+    key: "T",
+    modifiers: { ctrl: !isMac(), meta: isMac(), shift: true },
+    handler: focusVariantSelector,
+    description: "focus thinking",
+    context: "global",
+  })
 }

packages/ui/src/stores/preferences.tsx

@@ -39,6 +39,7 @@ export interface Preferences {
   lastUsedBinary?: string
   environmentVariables: Record<string, string>
   modelRecents: ModelPreference[]
+  modelThinkingSelections: Record<string, string>
   diffViewMode: DiffViewMode
   toolOutputExpansion: ExpansionPreference
   diagnosticsExpansion: ExpansionPreference
@@ -71,6 +72,7 @@ const defaultPreferences: Preferences = {
   showTimelineTools: true,
   environmentVariables: {},
   modelRecents: [],
+  modelThinkingSelections: {},
   diffViewMode: "split",
   toolOutputExpansion: "expanded",
   diagnosticsExpansion: "expanded",
@@ -102,6 +104,11 @@ function normalizePreferences(pref?: Partial<Preferences> & { agentModelSelectio
   const sourceModelRecents = sanitized.modelRecents ?? defaultPreferences.modelRecents
   const modelRecents = sourceModelRecents.map((item) => ({ ...item }))
 
+  const modelThinkingSelections = {
+    ...defaultPreferences.modelThinkingSelections,
+    ...(sanitized.modelThinkingSelections ?? {}),
+  }
+
   return {
     showThinkingBlocks: sanitized.showThinkingBlocks ?? defaultPreferences.showThinkingBlocks,
     thinkingBlocksExpansion: sanitized.thinkingBlocksExpansion ?? defaultPreferences.thinkingBlocksExpansion,
@@ -109,6 +116,7 @@ function normalizePreferences(pref?: Partial<Preferences> & { agentModelSelectio
     lastUsedBinary: sanitized.lastUsedBinary ?? defaultPreferences.lastUsedBinary,
     environmentVariables,
     modelRecents,
+    modelThinkingSelections,
     diffViewMode: sanitized.diffViewMode ?? defaultPreferences.diffViewMode,
     toolOutputExpansion: sanitized.toolOutputExpansion ?? defaultPreferences.toolOutputExpansion,
     diagnosticsExpansion: sanitized.diagnosticsExpansion ?? defaultPreferences.diagnosticsExpansion,
@@ -118,6 +126,35 @@ function normalizePreferences(pref?: Partial<Preferences> & { agentModelSelectio
   }
 }
 
+function getModelKey(model: { providerId: string; modelId: string }): string {
+  return `${model.providerId}/${model.modelId}`
+}
+
+function getModelThinkingSelection(model: { providerId: string; modelId: string }): string | undefined {
+  if (!model.providerId || !model.modelId) return undefined
+  return preferences().modelThinkingSelections?.[getModelKey(model)]
+}
+
+function setModelThinkingSelection(model: { providerId: string; modelId: string }, value: string | undefined): void {
+  if (!model.providerId || !model.modelId) return
+  const key = getModelKey(model)
+  const current = preferences().modelThinkingSelections?.[key]
+  if (current === value) return
+
+  updateConfig((draft) => {
+    const selections = { ...(draft.preferences.modelThinkingSelections ?? {}) }
+    if (!value) {
+      delete selections[key]
+    } else {
+      selections[key] = value
+    }
+    draft.preferences = normalizePreferences({
+      ...draft.preferences,
+      modelThinkingSelections: selections,
+    })
+  })
+}
+
 const [internalConfig, setInternalConfig] = createSignal<ConfigData>(buildFallbackConfig())
 
 const config = createMemo<DeepReadonly<ConfigData>>(() => internalConfig())
@@ -527,6 +564,8 @@ export {
   addEnvironmentVariable,
   removeEnvironmentVariable,
   addRecentModelPreference,
+  getModelThinkingSelection,
+  setModelThinkingSelection,
   setAgentModelPreference,
   getAgentModelPreference,
   setDiffViewMode,
@@ -540,4 +579,3 @@ export {
  }
  
 
-

packages/ui/src/stores/session-actions.ts

@@ -1,8 +1,8 @@
 import { resolvePastedPlaceholders } from "../lib/prompt-placeholders"
 import { instances } from "./instances"
 
-import { addRecentModelPreference, setAgentModelPreference } from "./preferences"
-import { sessions, withSession } from "./session-state"
+import { addRecentModelPreference, getModelThinkingSelection, setAgentModelPreference } from "./preferences"
+import { providers, sessions, withSession } from "./session-state"
 import { getDefaultModel, isModelValid } from "./session-models"
 import { updateSessionInfo } from "./message-v2/session-info"
 import { messageStoreBus } from "./message-v2/bus"
@@ -11,6 +11,22 @@ import { requestData } from "../lib/opencode-api"
 
 const log = getLogger("actions")
 
+function getVariantKeysForModel(instanceId: string, model: { providerId: string; modelId: string }): string[] {
+  if (!model.providerId || !model.modelId) return []
+  const instanceProviders = providers().get(instanceId) || []
+  const provider = instanceProviders.find((p) => p.id === model.providerId)
+  const match = provider?.models.find((m) => m.id === model.modelId)
+  return match?.variantKeys ?? []
+}
+
+function getThinkingVariantToSend(instanceId: string, model: { providerId: string; modelId: string }): string | undefined {
+  const selected = getModelThinkingSelection(model)
+  if (!selected) return undefined
+  const keys = getVariantKeysForModel(instanceId, model)
+  if (keys.length === 0) return undefined
+  return keys.includes(selected) ? selected : undefined
+}
+
 const ID_LENGTH = 26
 const BASE62_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
 
@@ -170,6 +186,12 @@ async function sendMessage(
           modelID: session.model.modelId,
         },
       }),
+    ...(session.model.providerId &&
+      session.model.modelId &&
+      (() => {
+        const variant = getThinkingVariantToSend(instanceId, session.model)
+        return variant ? { variant } : {}
+      })()),
   }
 
   log.info("sendMessage", {
@@ -215,6 +237,7 @@ async function executeCustomCommand(
     messageID: string
     agent?: string
     model?: string
+    variant?: string
   } = {
     command: commandName,
     arguments: args,
@@ -227,6 +250,8 @@ async function executeCustomCommand(
 
   if (session.model.providerId && session.model.modelId) {
     body.model = `${session.model.providerId}/${session.model.modelId}`
+    const variant = getThinkingVariantToSend(instanceId, session.model)
+    if (variant) body.variant = variant
   }
 
   await requestData(

packages/ui/src/stores/session-api.ts

@@ -483,6 +483,7 @@ async function fetchProviders(instanceId: string): Promise<void> {
         providerId: provider.id,
         limit: model.limit,
         cost: model.cost,
+        variantKeys: Object.keys(model.variants ?? {}),
       })),
     }))
 

packages/ui/src/styles/panels/session-layout.css

@@ -121,21 +121,26 @@ session-sidebar-controls .selector-trigger-primary {
 }
 
 .sidebar-selector-hints {
-  @apply flex items-center gap-2 w-full;
-  justify-content: space-between;
+  @apply grid gap-2 w-full;
+  grid-template-columns: repeat(3, minmax(0, 1fr));
 }
 
 .sidebar-selector-hint--left,
+.sidebar-selector-hint--center,
 .sidebar-selector-hint--right {
-  @apply flex-1;
+  justify-content: center;
 }
 
-.sidebar-selector-hint--left {
-  justify-content: flex-start;
+@media (max-width: 520px) {
+  .sidebar-selector-hints {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+  }
 }
 
-.sidebar-selector-hint--right {
-  justify-content: flex-end;
+@media (max-width: 360px) {
+  .sidebar-selector-hints {
+    grid-template-columns: 1fr;
+  }
 }
 
 .session-header-hints {

packages/ui/src/types/session.ts

@@ -85,6 +85,7 @@ export interface Model {
   id: string
   name: string
   providerId: string
+  variantKeys?: string[]
   limit?: {
     context?: number
     output?: number