diff --git a/packages/ui/src/App.tsx b/packages/ui/src/App.tsx
index b02861c1..5ad213a6 100644
--- a/packages/ui/src/App.tsx
+++ b/packages/ui/src/App.tsx
@@ -72,6 +72,7 @@ const App: Component = () => {
     setToolOutputExpansion,
     setDiagnosticsExpansion,
     setThinkingBlocksExpansion,
+    setToolInputsVisibility,
   } = useConfig()
   const [escapeInDebounce, setEscapeInDebounce] = createSignal(false)
   interface LaunchErrorState {
@@ -402,6 +403,7 @@ const App: Component = () => {
     setToolOutputExpansion,
     setDiagnosticsExpansion,
     setThinkingBlocksExpansion,
+    setToolInputsVisibility,
     handleNewInstanceRequest,
     handleCloseInstance,
     handleNewSession,
diff --git a/packages/ui/src/components/tool-call.tsx b/packages/ui/src/components/tool-call.tsx
index 458de294..445a1250 100644
--- a/packages/ui/src/components/tool-call.tsx
+++ b/packages/ui/src/components/tool-call.tsx
@@ -84,7 +84,7 @@ interface ToolCallProps {
 
 
 export default function ToolCall(props: ToolCallProps) {
-  const { preferences, setDiffViewMode } = useConfig()
+  const { preferences, setDiffViewMode, setToolInputsVisibility } = useConfig()
   const { isDark } = useTheme()
   const { t } = useI18n()
   const toolCallMemo = createMemo(() => props.toolCall)
@@ -172,9 +172,21 @@ export default function ToolCall(props: ToolCallProps) {
   })
 
   const [userExpanded, setUserExpanded] = createSignal<boolean | null>(null)
-  const [inputVisible, setInputVisible] = createSignal(false)
-  const [inputSectionExpanded, setInputSectionExpanded] = createSignal(false)
-  const [outputSectionExpanded, setOutputSectionExpanded] = createSignal(true)
+  const toolInputsVisibility = createMemo(() => preferences().toolInputsVisibility || "hidden")
+  const isToolInputVisible = createMemo(() => toolInputsVisibility() !== "hidden")
+  const inputDefaultExpanded = createMemo(() => toolInputsVisibility() === "expanded")
+  const [inputSectionOverride, setInputSectionOverride] = createSignal<boolean | null>(null)
+  const [outputSectionOverride, setOutputSectionOverride] = createSignal<boolean | null>(null)
+  const inputSectionExpanded = () => {
+    const override = inputSectionOverride()
+    if (override !== null) return override
+    return inputDefaultExpanded()
+  }
+  const outputSectionExpanded = () => {
+    const override = outputSectionOverride()
+    if (override !== null) return override
+    return true
+  }
 
   const isPermissionActive = createMemo(() => {
     const pending = pendingPermission()
@@ -591,22 +603,24 @@ export default function ToolCall(props: ToolCallProps) {
     })
   }
 
+  createEffect(() => {
+    // When global preference changes, reset per-tool-call overrides so palette changes apply.
+    toolInputsVisibility()
+    setInputSectionOverride(null)
+    setOutputSectionOverride(null)
+  })
+
   const handleToggleInputVisibility = (event: MouseEvent) => {
     event.preventDefault()
     event.stopPropagation()
     if (!expanded()) {
       toggle()
     }
-    setInputVisible((prev) => {
-      const next = !prev
-      if (!next) {
-        setInputSectionExpanded(false)
-      } else {
-        setInputSectionExpanded(true)
-        setOutputSectionExpanded(true)
-      }
-      return next
-    })
+    if (isToolInputVisible()) {
+      setToolInputsVisibility("hidden")
+      return
+    }
+    setToolInputsVisibility("expanded")
   }
 
   const renderer = createMemo(() => resolveToolRenderer(toolName()))
@@ -855,13 +869,13 @@ export default function ToolCall(props: ToolCallProps) {
             type="button"
             class="tool-call-header-input"
             onClick={handleToggleInputVisibility}
-            aria-pressed={inputVisible()}
+            aria-pressed={isToolInputVisible()}
             aria-label={
-              inputVisible()
+              isToolInputVisible()
                 ? t("toolCall.header.hideInputAriaLabel")
                 : t("toolCall.header.showInputAriaLabel")
             }
-            title={inputVisible() ? t("toolCall.header.hideInputTitle") : t("toolCall.header.showInputTitle")}
+            title={isToolInputVisible() ? t("toolCall.header.hideInputTitle") : t("toolCall.header.showInputTitle")}
           >
             <ArrowRightSquare class="w-3.5 h-3.5" />
           </button>
@@ -885,7 +899,7 @@ export default function ToolCall(props: ToolCallProps) {
       {expanded() && (
         <div class="tool-call-details">
           <Show
-            when={inputVisible() && hasToolInput()}
+            when={isToolInputVisible() && hasToolInput()}
             fallback={
               <>
                 {renderToolBody()}
@@ -906,7 +920,10 @@ export default function ToolCall(props: ToolCallProps) {
                   type="button"
                   class="tool-call-io-toggle"
                   aria-expanded={inputSectionExpanded()}
-                  onClick={() => setInputSectionExpanded((prev) => !prev)}
+                  onClick={() => setInputSectionOverride((prev) => {
+                    const current = prev === null ? inputSectionExpanded() : prev
+                    return !current
+                  })}
                 >
                   <span class="tool-call-io-title">{t("toolCall.io.input")}</span>
                 </button>
@@ -927,7 +944,10 @@ export default function ToolCall(props: ToolCallProps) {
                   type="button"
                   class="tool-call-io-toggle"
                   aria-expanded={outputSectionExpanded()}
-                  onClick={() => setOutputSectionExpanded((prev) => !prev)}
+                  onClick={() => setOutputSectionOverride((prev) => {
+                    const current = prev === null ? outputSectionExpanded() : prev
+                    return !current
+                  })}
                 >
                   <span class="tool-call-io-title">{t("toolCall.io.output")}</span>
                 </button>
diff --git a/packages/ui/src/lib/hooks/use-commands.ts b/packages/ui/src/lib/hooks/use-commands.ts
index c89a95d4..4105e274 100644
--- a/packages/ui/src/lib/hooks/use-commands.ts
+++ b/packages/ui/src/lib/hooks/use-commands.ts
@@ -1,6 +1,6 @@
 import { createSignal, onMount } from "solid-js"
 import type { Accessor } from "solid-js"
-import type { Preferences, ExpansionPreference } from "../../stores/preferences"
+import type { Preferences, ExpansionPreference, ToolInputsVisibilityPreference } from "../../stores/preferences"
 import { createCommandRegistry, type Command } from "../commands"
 import { instances, activeInstanceId, setActiveInstanceId } from "../../stores/instances"
 import type { ClientPart, MessageInfo } from "../../types/message"
@@ -38,6 +38,7 @@ export interface UseCommandsOptions {
   setToolOutputExpansion: (mode: ExpansionPreference) => void
   setDiagnosticsExpansion: (mode: ExpansionPreference) => void
   setThinkingBlocksExpansion: (mode: ExpansionPreference) => void
+  setToolInputsVisibility: (mode: ToolInputsVisibilityPreference) => void
   handleNewInstanceRequest: () => void
   handleCloseInstance: (instanceId: string) => Promise<void>
   handleNewSession: (instanceId: string) => Promise<void>
@@ -551,6 +552,29 @@ export function useCommands(options: UseCommandsOptions) {
       },
     })
 
+    commandRegistry.register({
+      id: "tool-inputs-visibility",
+      label: () => {
+        const mode = options.preferences().toolInputsVisibility || "hidden"
+        const state =
+          mode === "expanded"
+            ? tGlobal("commands.common.expanded")
+            : mode === "collapsed"
+              ? tGlobal("commands.common.collapsed")
+              : tGlobal("commands.common.hidden")
+        return tGlobal("commands.toolInputsVisibility.label", { state })
+      },
+      description: () => tGlobal("commands.toolInputsVisibility.description"),
+      category: "System",
+      keywords: () => splitKeywords("commands.toolInputsVisibility.keywords"),
+      action: () => {
+        const mode = options.preferences().toolInputsVisibility || "hidden"
+        const next: ToolInputsVisibilityPreference =
+          mode === "hidden" ? "collapsed" : mode === "collapsed" ? "expanded" : "hidden"
+        options.setToolInputsVisibility(next)
+      },
+    })
+
     commandRegistry.register({
       id: "token-usage-visibility",
       label: () => {
diff --git a/packages/ui/src/lib/i18n/messages/en/commands.ts b/packages/ui/src/lib/i18n/messages/en/commands.ts
index dd0d12f7..b396200c 100644
--- a/packages/ui/src/lib/i18n/messages/en/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/en/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "Toggle default expansion for diagnostics output",
   "commands.diagnosticsDefault.keywords": "diagnostics, expand, collapse",
 
+  "commands.toolInputsVisibility.label": "Tool Inputs Visibility · {state}",
+  "commands.toolInputsVisibility.description": "Set default visibility for tool call input arguments",
+  "commands.toolInputsVisibility.keywords": "tool, inputs, arguments, visibility, hide, show, expand, collapse",
+
   "commands.tokenUsageDisplay.label": "Token Usage Display · {state}",
   "commands.tokenUsageDisplay.description": "Show or hide token and cost stats for assistant messages",
   "commands.tokenUsageDisplay.keywords": "token, usage, cost, stats",
diff --git a/packages/ui/src/lib/i18n/messages/es/commands.ts b/packages/ui/src/lib/i18n/messages/es/commands.ts
index c6a75e7e..43e1fbb1 100644
--- a/packages/ui/src/lib/i18n/messages/es/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/es/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "Alternar la expansión por defecto de la salida de diagnósticos",
   "commands.diagnosticsDefault.keywords": "diagnósticos, expandir, colapsar",
 
+  "commands.toolInputsVisibility.label": "Visibilidad de entradas de herramientas · {state}",
+  "commands.toolInputsVisibility.description": "Configurar la visibilidad por defecto de los argumentos de entrada de llamadas de herramienta",
+  "commands.toolInputsVisibility.keywords": "herramienta, entradas, argumentos, visibilidad, ocultar, mostrar, expandir, colapsar",
+
   "commands.tokenUsageDisplay.label": "Mostrar uso de tokens · {state}",
   "commands.tokenUsageDisplay.description": "Mostrar u ocultar estadísticas de tokens y costo en los mensajes del asistente",
   "commands.tokenUsageDisplay.keywords": "token, uso, costo, estadísticas",
diff --git a/packages/ui/src/lib/i18n/messages/fr/commands.ts b/packages/ui/src/lib/i18n/messages/fr/commands.ts
index 63e7c666..505baa19 100644
--- a/packages/ui/src/lib/i18n/messages/fr/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/fr/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "Choisir l'ouverture par défaut de la sortie des diagnostics",
   "commands.diagnosticsDefault.keywords": "diagnostics, développer, réduire",
 
+  "commands.toolInputsVisibility.label": "Visibilité des entrées d'outil · {state}",
+  "commands.toolInputsVisibility.description": "Définir la visibilité par défaut des arguments d'entrée des appels d'outil",
+  "commands.toolInputsVisibility.keywords": "outil, entrées, arguments, visibilité, masquer, afficher, développer, réduire",
+
   "commands.tokenUsageDisplay.label": "Affichage de l'usage des tokens · {state}",
   "commands.tokenUsageDisplay.description": "Afficher ou masquer les stats de tokens et de coût pour les messages de l'assistant",
   "commands.tokenUsageDisplay.keywords": "token, usage, coût, stats",
diff --git a/packages/ui/src/lib/i18n/messages/ja/commands.ts b/packages/ui/src/lib/i18n/messages/ja/commands.ts
index 75c1c5f3..de21f94c 100644
--- a/packages/ui/src/lib/i18n/messages/ja/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/ja/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "診断出力を既定で展開するか切り替え",
   "commands.diagnosticsDefault.keywords": "診断, 展開, 折りたたみ, diagnostics, expand, collapse",
 
+  "commands.toolInputsVisibility.label": "ツール入力の表示 · {state}",
+  "commands.toolInputsVisibility.description": "ツール呼び出しの入力引数の既定の表示状態を設定します",
+  "commands.toolInputsVisibility.keywords": "ツール, 入力, 引数, 表示, 非表示, 展開, 折りたたみ, tool, inputs, arguments, visibility, hide, show, expand, collapse",
+
   "commands.tokenUsageDisplay.label": "トークン使用量表示 · {state}",
   "commands.tokenUsageDisplay.description": "アシスタントメッセージのトークン/コスト統計を表示/非表示",
   "commands.tokenUsageDisplay.keywords": "トークン, 使用量, コスト, 統計, token, usage, cost, stats",
diff --git a/packages/ui/src/lib/i18n/messages/ru/commands.ts b/packages/ui/src/lib/i18n/messages/ru/commands.ts
index 068f020d..55d2a791 100644
--- a/packages/ui/src/lib/i18n/messages/ru/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/ru/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "Переключить, разворачивать ли вывод диагностики по умолчанию",
   "commands.diagnosticsDefault.keywords": "diagnostics, развернуть, свернуть",
 
+  "commands.toolInputsVisibility.label": "Видимость входных данных инструмента · {state}",
+  "commands.toolInputsVisibility.description": "Установить видимость аргументов входа вызовов инструментов по умолчанию",
+  "commands.toolInputsVisibility.keywords": "инструмент, вход, аргументы, видимость, скрыть, показать, раскрыть, свернуть, tool, inputs, arguments, visibility, hide, show, expand, collapse",
+
   "commands.tokenUsageDisplay.label": "Отображение token-статистики · {state}",
   "commands.tokenUsageDisplay.description": "Показать или скрыть статистику token и стоимости для сообщений ассистента",
   "commands.tokenUsageDisplay.keywords": "token, usage, cost, статистика",
diff --git a/packages/ui/src/lib/i18n/messages/zh-Hans/commands.ts b/packages/ui/src/lib/i18n/messages/zh-Hans/commands.ts
index 85997488..69eba72f 100644
--- a/packages/ui/src/lib/i18n/messages/zh-Hans/commands.ts
+++ b/packages/ui/src/lib/i18n/messages/zh-Hans/commands.ts
@@ -130,6 +130,10 @@ export const commandMessages = {
   "commands.diagnosticsDefault.description": "切换诊断输出是否默认展开",
   "commands.diagnosticsDefault.keywords": "diagnostics, expand, collapse, 诊断, 展开, 折叠",
 
+  "commands.toolInputsVisibility.label": "工具输入可见性 · {state}",
+  "commands.toolInputsVisibility.description": "设置工具调用输入参数的默认可见性",
+  "commands.toolInputsVisibility.keywords": "工具, 输入, 参数, 可见性, 隐藏, 显示, 展开, 折叠, tool, inputs, arguments, visibility, hide, show, expand, collapse",
+
   "commands.tokenUsageDisplay.label": "Token 使用显示 · {state}",
   "commands.tokenUsageDisplay.description": "显示或隐藏助手消息的 token 和费用统计",
   "commands.tokenUsageDisplay.keywords": "token, usage, cost, stats, 令牌, 用量, 费用, 统计",
diff --git a/packages/ui/src/stores/preferences.tsx b/packages/ui/src/stores/preferences.tsx
index 00b0a04e..520e6726 100644
--- a/packages/ui/src/stores/preferences.tsx
+++ b/packages/ui/src/stores/preferences.tsx
@@ -25,6 +25,7 @@ export interface ModelPreference {
 
 export type DiffViewMode = "split" | "unified"
 export type ExpansionPreference = "expanded" | "collapsed"
+export type ToolInputsVisibilityPreference = "hidden" | "collapsed" | "expanded"
 export type ListeningMode = "local" | "all"
 
 export interface UiSettings {
@@ -37,6 +38,7 @@ export interface UiSettings {
   diffViewMode: DiffViewMode
   toolOutputExpansion: ExpansionPreference
   diagnosticsExpansion: ExpansionPreference
+  toolInputsVisibility: ToolInputsVisibilityPreference
   showUsageMetrics: boolean
   autoCleanupBlankSessions: boolean
 
@@ -108,6 +110,7 @@ const defaultUiSettings: UiSettings = {
   diffViewMode: "split",
   toolOutputExpansion: "expanded",
   diagnosticsExpansion: "expanded",
+  toolInputsVisibility: "hidden",
   showUsageMetrics: true,
   autoCleanupBlankSessions: true,
 
@@ -130,6 +133,10 @@ function normalizeUiSettings(input?: Partial<UiSettings> | null): UiSettings {
     diffViewMode: sanitized.diffViewMode ?? defaultUiSettings.diffViewMode,
     toolOutputExpansion: sanitized.toolOutputExpansion ?? defaultUiSettings.toolOutputExpansion,
     diagnosticsExpansion: sanitized.diagnosticsExpansion ?? defaultUiSettings.diagnosticsExpansion,
+    toolInputsVisibility:
+      sanitized.toolInputsVisibility === "collapsed" || sanitized.toolInputsVisibility === "expanded"
+        ? sanitized.toolInputsVisibility
+        : defaultUiSettings.toolInputsVisibility,
     showUsageMetrics: sanitized.showUsageMetrics ?? defaultUiSettings.showUsageMetrics,
     autoCleanupBlankSessions: sanitized.autoCleanupBlankSessions ?? defaultUiSettings.autoCleanupBlankSessions,
     osNotificationsEnabled: sanitized.osNotificationsEnabled ?? defaultUiSettings.osNotificationsEnabled,
@@ -439,6 +446,11 @@ function setDiagnosticsExpansion(mode: ExpansionPreference): void {
   updateUiSettings({ diagnosticsExpansion: mode })
 }
 
+function setToolInputsVisibility(mode: ToolInputsVisibilityPreference): void {
+  if (preferences().toolInputsVisibility === mode) return
+  updateUiSettings({ toolInputsVisibility: mode })
+}
+
 function setThinkingBlocksExpansion(mode: ExpansionPreference): void {
   if (preferences().thinkingBlocksExpansion === mode) return
   updateUiSettings({ thinkingBlocksExpansion: mode })
@@ -536,6 +548,7 @@ interface ConfigContextValue {
   setToolOutputExpansion: typeof setToolOutputExpansion
   setDiagnosticsExpansion: typeof setDiagnosticsExpansion
   setThinkingBlocksExpansion: typeof setThinkingBlocksExpansion
+  setToolInputsVisibility: typeof setToolInputsVisibility
 
   // instance scoped
   setAgentModelPreference: typeof setAgentModelPreference
@@ -579,6 +592,7 @@ const configContextValue: ConfigContextValue = {
   setToolOutputExpansion,
   setDiagnosticsExpansion,
   setThinkingBlocksExpansion,
+  setToolInputsVisibility,
   setAgentModelPreference,
   getAgentModelPreference,
 }