feat(settings): 侧边栏设置声明式化 — 注册表驱动的开关清单 + 内置支持插头化

- SidebarPrefs 新增 tabsEnabled / viewersEnabled 开放 map（缺省 = 启用），
  PrefsSchema 用 z.dict 校验，旧文档零迁移
- TabDescriptor/FileViewerDescriptor 新增声明式设置面：viewer 补 title/icon，
  两者补 settings.toggles（子代理声明 autoOpenSubagent、终端声明 agentTerminalTools）
- 服务新增 isTabEnabled/isViewerEnabled；openTab 拒绝禁用类型、matchFileViewer
  跳过禁用 viewer
- SideCardSection 重写为注册表驱动清单：侧边栏内容（图标+类型id+开关+嵌套开关）
  + 文件预览（图标+标题+扩展名+开关），开关持久化 + 乐观提交回滚
- 消费点 gating：+ 菜单过滤、子代理自动展开、agent 终端 reconcile、
  产出文件拦截（editor 关闭时回落默认行）、新会话 explorer 预置
- 内置 viewer 补 6 个手绘 outline 图标；store 快照携带 prefs 使开关变更即时生效
- 测试：service gating / builtins 声明 / parsePrefs map 校验 / schema 断言 /
  新增 SideCardSection renderToString 规格
- 文档：README 设置小节、AGENTS.md 描述符与服务方法、新增设计文档；版本 0.5.0

src/client/SideCardSection.module.css

@@ -25,6 +25,43 @@
   cursor: pointer;
 }
 
+/* Nested declarative toggle (a tab's related setting): indented child row. */
+.subRow {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 16px;
+  padding: 10px 0 10px 28px;
+  border-bottom: 1px solid var(--dsw-alias-border-l2);
+  cursor: pointer;
+}
+
+/* Inventory section heading (侧边栏内容 / 文件预览). */
+.sectionHeading {
+  padding: 18px 0 6px;
+  font-size: 12px;
+  line-height: 17px;
+  font-weight: 600;
+  letter-spacing: 0.02em;
+  color: var(--dsw-alias-label-secondary);
+}
+
+/* Icon of one inventory row, inline with the title. */
+.rowIcon {
+  display: inline-flex;
+  align-items: center;
+  flex: none;
+  color: var(--dsw-alias-label-secondary);
+}
+
+/* Title with the icon beside it. */
+.titleLine {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  min-width: 0;
+}
+
 .rowText {
   display: flex;
   flex-direction: column;

src/client/SideCardSection.tsx

@@ -1,20 +1,30 @@
 /**
  * "Side card" settings section: the user-facing preferences for the sidebar
  * panel, rendered natively in the DSH Settings shell (nav label "Side card").
- * Three rows:
- *  - new conversations open the panel by default (native checkbox),
- *  - the default panel width as a percent of the window (number input + %),
- *  - auto-open the Subagent page when a new subagent appears (native checkbox,
- *    on by default).
+ *
+ * The section is DECLARATIVE — it renders the enable/disable inventory from
+ * the sidebar service's registries instead of hardcoding rows:
+ *  - 常规: new conversations open the panel by default (native checkbox),
+ *    and the default panel width as a percent of the window (number input).
+ *  - 侧边栏内容: one row per REGISTERED tab type (built-ins and external
+ *    plugins alike) — icon + title + type id + an on/off switch persisted in
+ *    `prefs.tabsEnabled[id]`. A tab's `settings.toggles` declaration renders
+ *    as nested switches under its row while the tab is enabled (e.g. the
+ *    Subagent page's "auto-open when a subagent appears").
+ *  - 文件预览: one row per REGISTERED file viewer — icon + title + the
+ *    extensions it covers + an on/off switch persisted in
+ *    `prefs.viewersEnabled[id]`.
  *
  * Writes ride the plugin's own fenced settings route (the host calls the
  * settings seam in-process — the DSH settings RPC domain does not serve
  * third-party namespaces to configuration clients); the shared SidebarStore
  * is refreshed on success so the very next brand-new session seeds from the
- * new values. Any failure reverts the optimistic UI and shows the wire error
- * inline — a broken settings surface never crashes the shell.
+ * new values and the sidebar's consumption points (the + menu, derived
+ * flows) re-render immediately. Any failure reverts the optimistic UI and
+ * shows the wire error inline — a broken settings surface never crashes the
+ * shell.
  */
-import { useEffect, useRef, useState } from 'react'
+import { Fragment, useEffect, useRef, useState, type ReactNode } from 'react'
 import { Input } from '@deepseek-ai/dsh-client-ui-primitives'
 // Type-only: pulls the settings shell's SlotMap merges ('settings.section').
 import type {} from '@deepseek-ai/dsh-client-ui-settings/client'
@@ -29,11 +39,18 @@ import { api } from './api.ts'
 import { parsePrefs } from './prefs.ts'
 import { t } from './locales.ts'
 import type { SidebarStore } from './state.ts'
+import type {
+  BetterSidebarService,
+  FileViewerDescriptor,
+  SidebarSettingToggle,
+  TabDescriptor,
+} from './service.ts'
 import css from './SideCardSection.module.css'
 
-/** Injected business face: the shared store (prefs cache). */
+/** Injected business face: the shared store (prefs cache) + the sidebar service (registries). */
 export interface SideCardSectionInjected {
   store: SidebarStore
+  service: BetterSidebarService
 }
 
 /** Full section props: the runtime share plus the injected face. */
@@ -47,16 +64,54 @@ function messageOf(error: unknown): string {
   return `${t('settingsSaveFailed')} ${error instanceof Error ? error.message : String(error)}`
 }
 
+/** Resolve an i18n-friendly string-or-function value. */
+function textOf(value: string | (() => string) | undefined): string {
+  if (value === undefined) return ''
+  return typeof value === 'function' ? value() : value
+}
+
+/** Resolve a descriptor icon (ReactNode or size function). */
+function iconOf(icon: ReactNode | ((size: number) => ReactNode) | undefined, size: number): ReactNode {
+  if (icon === undefined) return null
+  return typeof icon === 'function' ? icon(size) : icon
+}
+
+/** Tab inventory order: hidden types (editor/diff) last, then + menu order. */
+function tabOrder(a: TabDescriptor, b: TabDescriptor): number {
+  if (a.hidden !== b.hidden) return a.hidden === true ? 1 : -1
+  return (a.order ?? 100) - (b.order ?? 100)
+}
+
+/** Viewer inventory order: priority desc (the catch-all `code` comes last). */
+function viewerOrder(a: FileViewerDescriptor, b: FileViewerDescriptor): number {
+  return (b.priority ?? 0) - (a.priority ?? 0)
+}
+
+/** Read one boolean pref by declarative key (missing = false). */
+function prefBool(prefs: SidebarPrefs, key: string): boolean {
+  return (prefs as unknown as Record<string, boolean>)[key] === true
+}
+
 /**
  * Render the Side card preferences section.
- * @param props - composed slot props (runtime share + injected store).
+ * @param props - composed slot props (runtime share + injected store/service).
  * @returns the section element tree.
  */
-export function SideCardSection({ store }: SideCardSectionProps) {
+export function SideCardSection({ store, service }: SideCardSectionProps) {
   const [prefs, setPrefs] = useState<SidebarPrefs>(() => store.getPrefs())
   const [widthDraft, setWidthDraft] = useState<string>(String(store.getPrefs().defaultWidthPercent))
   const [error, setError] = useState<string | null>(null)
 
+  // The declarative inventory: the registered tab types and file viewers.
+  // Local state + service.subscribe (registry changes are rare — plugin
+  // load/unload — so a plain effect is enough; no external-store ceremony).
+  const [tabs, setTabs] = useState<TabDescriptor[]>(() => [...service.getTabs()].sort(tabOrder))
+  const [viewers, setViewers] = useState<FileViewerDescriptor[]>(() => [...service.getFileViewers()].sort(viewerOrder))
+  useEffect(() => service.subscribe(() => {
+    setTabs([...service.getTabs()].sort(tabOrder))
+    setViewers([...service.getFileViewers()].sort(viewerOrder))
+  }), [service])
+
   // The settings document revision (guards concurrent writes). A ref: commits
   // read the freshest value at execution time, no re-render needed.
   const revisionRef = useRef<number | undefined>(undefined)
@@ -84,7 +139,7 @@ export function SideCardSection({ store }: SideCardSectionProps) {
   }, [])
 
   /** Persist one patch through the settings route (serialized, revision-guarded). */
-  const commit = (patch: Partial<SidebarPrefs>): Promise<{ ok: boolean; prefs: SidebarPrefs }> => {
+  const commit = (patch: Record<string, unknown>): Promise<{ ok: boolean; prefs: SidebarPrefs }> => {
     dirtyRef.current = true
     const run = inFlightRef.current.then(async () => {
       const view = await api.settingsUpdate(
@@ -114,25 +169,31 @@ export function SideCardSection({ store }: SideCardSectionProps) {
     setWidthDraft(String(settled.defaultWidthPercent))
   }
 
+  /** Optimistically flip one boolean pref, then commit (revert on failure). */
+  const togglePref = (patch: Record<string, unknown>): void => {
+    const previous = prefs
+    setPrefs({ ...previous, ...patch } as SidebarPrefs)
+    setError(null)
+    void commit(patch).then(outcome => applyOutcome(previous, outcome))
+  }
+
   const onToggle = (next: boolean): void => {
-    const previous = prefs
-    setPrefs({ ...previous, openByDefault: next })
-    setError(null)
-    void commit({ openByDefault: next }).then(outcome => applyOutcome(previous, outcome))
+    togglePref({ openByDefault: next })
   }
 
-  const onToggleSubagent = (next: boolean): void => {
-    const previous = prefs
-    setPrefs({ ...previous, autoOpenSubagent: next })
-    setError(null)
-    void commit({ autoOpenSubagent: next }).then(outcome => applyOutcome(previous, outcome))
+  /** Flip one per-tab enable switch (merge into the tabsEnabled map). */
+  const onToggleTab = (id: string, next: boolean): void => {
+    togglePref({ tabsEnabled: { ...prefs.tabsEnabled, [id]: next } })
   }
 
-  const onToggleTools = (next: boolean): void => {
-    const previous = prefs
-    setPrefs({ ...previous, agentTerminalTools: next })
-    setError(null)
-    void commit({ agentTerminalTools: next }).then(outcome => applyOutcome(previous, outcome))
+  /** Flip one per-viewer enable switch (merge into the viewersEnabled map). */
+  const onToggleViewer = (id: string, next: boolean): void => {
+    togglePref({ viewersEnabled: { ...prefs.viewersEnabled, [id]: next } })
+  }
+
+  /** Flip one declaratively-declared toggle (a SidebarPrefs boolean field). */
+  const onToggleSetting = (toggle: SidebarSettingToggle, next: boolean): void => {
+    togglePref({ [toggle.key]: next })
   }
 
   const commitWidth = (): void => {
@@ -149,6 +210,34 @@ export function SideCardSection({ store }: SideCardSectionProps) {
     void commit({ defaultWidthPercent: clamped }).then(outcome => applyOutcome(previous, outcome))
   }
 
+  /** One enable/disable row: icon + title + desc + checkbox. */
+  const renderRow = (props: {
+    title: string
+    desc: string
+    icon?: ReactNode
+    checked: boolean
+    label: string
+    onToggle: (next: boolean) => void
+    sub?: boolean
+  }) => (
+    <label className={props.sub === true ? css.subRow : css.row}>
+      <span className={css.rowText}>
+        <span className={css.titleLine}>
+          {props.icon !== null && props.icon !== undefined && <span className={css.rowIcon}>{props.icon}</span>}
+          <span className={css.title}>{props.title}</span>
+        </span>
+        <span className={css.desc}>{props.desc}</span>
+      </span>
+      <input
+        type="checkbox"
+        className={css.toggle}
+        checked={props.checked}
+        aria-label={props.label}
+        onChange={event => { props.onToggle(event.currentTarget.checked) }}
+      />
+    </label>
+  )
+
   return (
     <div className={css.section}>
       <label className={css.row}>
@@ -187,32 +276,50 @@ export function SideCardSection({ store }: SideCardSectionProps) {
           <span className={css.suffix}>{t('settingsWidthSuffix')}</span>
         </span>
       </div>
-      <label className={css.row}>
-        <span className={css.rowText}>
-          <span className={css.title}>{t('settingsSubagentTitle')}</span>
-          <span className={css.desc}>{t('settingsSubagentDesc')}</span>
-        </span>
-        <input
-          type="checkbox"
-          className={css.toggle}
-          checked={prefs.autoOpenSubagent}
-          aria-label={t('settingsSubagentTitle')}
-          onChange={event => { onToggleSubagent(event.currentTarget.checked) }}
-        />
-      </label>
-      <label className={css.row}>
-        <span className={css.rowText}>
-          <span className={css.title}>{t('settingsToolsTitle')}</span>
-          <span className={css.desc}>{t('settingsToolsDesc')}</span>
-        </span>
-        <input
-          type="checkbox"
-          className={css.toggle}
-          checked={prefs.agentTerminalTools}
-          aria-label={t('settingsToolsTitle')}
-          onChange={event => { onToggleTools(event.currentTarget.checked) }}
-        />
-      </label>
+
+      {/* 侧边栏内容: one row per registered tab type, icon + type id + switch,
+          plus each tab's declaratively-declared nested toggles (shown only
+          while the tab itself is enabled). */}
+      <div className={css.sectionHeading}>{t('settingsTabsTitle')}</div>
+      {tabs.map(tab => (
+        <Fragment key={tab.id}>
+          {renderRow({
+            title: textOf(tab.title),
+            desc: tab.id,
+            icon: iconOf(tab.icon, 16),
+            checked: prefs.tabsEnabled[tab.id] !== false,
+            label: textOf(tab.title),
+            onToggle: (next) => { onToggleTab(tab.id, next) },
+          })}
+          {prefs.tabsEnabled[tab.id] !== false && (tab.settings?.toggles ?? []).map(toggle => (
+            <Fragment key={`${tab.id}:${toggle.key}`}>
+              {renderRow({
+                title: textOf(toggle.title),
+                desc: textOf(toggle.desc),
+                checked: prefBool(prefs, toggle.key),
+                label: textOf(toggle.title),
+                onToggle: (next) => { onToggleSetting(toggle, next) },
+                sub: true,
+              })}
+            </Fragment>
+          ))}
+        </Fragment>
+      ))}
+
+      {/* 文件预览: one row per registered file viewer, icon + title + exts + switch. */}
+      <div className={css.sectionHeading}>{t('settingsViewersTitle')}</div>
+      {viewers.map(viewer => (
+        <Fragment key={viewer.id}>
+          {renderRow({
+            title: textOf(viewer.title) || viewer.id,
+            desc: viewer.exts.length === 0 ? t('settingsViewerCatchAll') : viewer.exts.join(' · '),
+            icon: iconOf(viewer.icon, 16),
+            checked: prefs.viewersEnabled[viewer.id] !== false,
+            label: textOf(viewer.title) || viewer.id,
+            onToggle: (next) => { onToggleViewer(viewer.id, next) },
+          })}
+        </Fragment>
+      ))}
       {error !== null && (
         <div className={css.error} role="alert">
           {error}

src/client/Sidebar.tsx

@@ -65,12 +65,14 @@ function TabContent(props: {
 
 /** The + menu options for the current state, driven by the tab registry.
  * Hidden tabs (editor/diff) never show; `available` returning false shows
- * a disabled row (e.g. terminal at capacity) instead of hiding the option. */
+ * a disabled row (e.g. terminal at capacity) instead of hiding the option.
+ * Tabs the user disabled in the side card settings are filtered out
+ * entirely — re-enabling them is the settings page's job. */
 function buildNewTabOptions(state: SidebarState, ctx: Context, scope: SessionScope): NewTabOption[] {
   const service = ctx.betterSidebar
   if (service === undefined) return []
   return service.getTabs()
-    .filter(d => !d.hidden)
+    .filter(d => !d.hidden && service.isTabEnabled(d.id))
     .sort((a, b) => (a.order ?? 100) - (b.order ?? 100))
     .map(d => ({
       id: d.id,
@@ -127,6 +129,8 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
    * the same shell without losing the agent's work — capped like the
    * terminal view's own reconnect loop, so a refused endpoint never spins
    * forever (the next session switch restarts the loop).
+   * While the terminal tab type is disabled in settings, pushes are
+   * ignored (no auto-added tabs); re-enabling makes the next push converge.
    */
   useEffect(() => {
     if (sessionId === undefined) return
@@ -145,7 +149,9 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
         try {
           const list = JSON.parse(event.data) as Array<{ uuid: string; title: string; command: string; exited: boolean }>
           if (!Array.isArray(list)) return
-          store.reduce(s => reconcileAgentTerminals(s, list))
+          store.reduce(s => ctx.betterSidebar?.isTabEnabled('terminal') === false
+            ? s
+            : reconcileAgentTerminals(s, list))
         } catch {
           // Malformed push: ignore (the next push will reconcile).
         }
@@ -171,12 +177,13 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
 
   /**
    * Subagent auto-activation: the moment the current conversation spawns its
-   * FIRST direct subagent (a 0 → N transition on the list feed) and the
-   * "auto open" pref is on, open the panel (if collapsed) and focus the
-   * Subagent page (single-instance: an existing tab is focused, never
-   * duplicated). Switching to a session that already has subagents never
-   * triggers — its baseline starts at the current count — so a deliberate
-   * layout is never fought.
+   * FIRST direct subagent (a 0 → N transition on the list feed), the "auto
+   * open" pref is on, and the Subagent tab type is enabled in settings,
+   * open the panel (if collapsed) and focus the Subagent page
+   * (single-instance: an existing tab is focused, never duplicated).
+   * Switching to a session that already has subagents never triggers — its
+   * baseline starts at the current count — so a deliberate layout is never
+   * fought.
    */
   const listBaselineRef = useRef<SidebarSessionList | undefined>(undefined)
   useEffect(() => {
@@ -185,6 +192,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
     if (sessionId === undefined || prev === undefined) return
     if (!detectNewDirectSubagent(prev, sessionList, sessionId)) return
     if (!store.getPrefs().autoOpenSubagent) return
+    if (ctx.betterSidebar?.isTabEnabled('subagent') === false) return
     store.reduce(s => s.panelOpen ? s : togglePanel(s))
     ctx.betterSidebar?.openTab({ type: 'subagent', title: t('subagent') })
   }, [sessionList, sessionId, store, ctx])

src/client/builtins/tabs.tsx

@@ -80,6 +80,15 @@ export function builtinTabs(ctx: Context): readonly TabDescriptor[] {
       icon: (size: number) => <IconThinkOutline16 size={size} />,
       order: 30,
       single: true,
+      // Declarative settings: the auto-open switch renders under this row in
+      // the Side card settings page (the Subagent page's own related setting).
+      settings: {
+        toggles: [{
+          key: 'autoOpenSubagent',
+          title: () => t('settingsSubagentTitle'),
+          desc: () => t('settingsSubagentDesc'),
+        }],
+      },
       component: ({ ctx, scope, visible, onSubagentJump }) => (
         <SubagentView
           sessionId={scope.sessionId}
@@ -95,6 +104,16 @@ export function builtinTabs(ctx: Context): readonly TabDescriptor[] {
       icon: (size: number) => <IconTerminalOutline16 size={size} />,
       order: 40,
       available: (_ctx, _scope, state) => uiTerminalCount(state) < TERMINAL_LIMIT,
+      // Declarative settings: the model-facing terminal tools switch renders
+      // under this row in the Side card settings page (the Terminal page's
+      // own related setting; the host gates the toolset on it independently).
+      settings: {
+        toggles: [{
+          key: 'agentTerminalTools',
+          title: () => t('settingsToolsTitle'),
+          desc: () => t('settingsToolsDesc'),
+        }],
+      },
       createTab: (state) => {
         const count = uiTerminalCount(state)
         if (count >= TERMINAL_LIMIT) return null

src/client/builtins/viewers.tsx

@@ -5,13 +5,27 @@
  * `binary-download` viewer sniffs NUL bytes via `detect` for unknown
  * binaries and serves doc/xls/ppt by extension; `code` is the catch-all
  * (`exts: []`, lowest priority) that claims any file no other viewer did.
+ *
+ * Every viewer carries the declarative settings-surface fields — `title`
+ * and `icon` — so the Side card settings page can render the enable/disable
+ * inventory without hardcoding (eating our own dogfood).
  */
+import { IconCodeOutline16, IconDownloadOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
 import { DocxView, XlsxView } from '../office-view.tsx'
 import { PdfView } from '../PdfView.tsx'
 import { PptxView } from '../PptxView.tsx'
 import { TextEditor } from '../TextEditor.tsx'
 import { BinaryDownload } from '../binary-download.tsx'
+import {
+  IconImageOutline16,
+  IconMarkdownOutline16,
+  IconPdfOutline16,
+  IconDocxOutline16,
+  IconXlsxOutline16,
+  IconPptxOutline16,
+} from '../icons.tsx'
 import type { FileViewerDescriptor } from '../service.ts'
+import { t } from '../locales.ts'
 import css from '../sidebar.module.css'
 
 /** The 8 built-in file viewer descriptors. */
@@ -19,6 +33,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
   return [
     {
       id: 'image',
+      title: () => t('viewerImage'),
+      icon: (size: number) => <IconImageOutline16 size={size} />,
       exts: ['png', 'jpg', 'jpeg', 'gif', 'webp', 'svg', 'bmp', 'ico', 'avif'],
       fetchStrategy: 'mediaUrl',
       component: ({ mediaUrl: url, title }) => (
@@ -29,6 +45,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'pdf',
+      title: () => t('viewerPdf'),
+      icon: (size: number) => <IconPdfOutline16 size={size} />,
       exts: ['pdf'],
       fetchStrategy: 'mediaUrl',
       component: ({ scope, path, title }) => (
@@ -37,6 +55,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'docx',
+      title: () => t('viewerDocx'),
+      icon: (size: number) => <IconDocxOutline16 size={size} />,
       exts: ['docx'],
       fetchStrategy: 'mediaUrl',
       component: ({ scope, path, title }) => (
@@ -45,6 +65,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'xlsx',
+      title: () => t('viewerXlsx'),
+      icon: (size: number) => <IconXlsxOutline16 size={size} />,
       exts: ['xlsx'],
       fetchStrategy: 'mediaUrl',
       component: ({ scope, path, title }) => (
@@ -53,6 +75,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'pptx',
+      title: () => t('viewerPptx'),
+      icon: (size: number) => <IconPptxOutline16 size={size} />,
       exts: ['pptx'],
       fetchStrategy: 'mediaUrl',
       component: ({ scope, path, title }) => (
@@ -61,12 +85,16 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'markdown',
+      title: () => t('viewerMarkdown'),
+      icon: (size: number) => <IconMarkdownOutline16 size={size} />,
       exts: ['md', 'markdown'],
       fetchStrategy: 'fsRead',
       component: (props) => <TextEditor {...props} />,
     },
     {
       id: 'code',
+      title: () => t('viewerCode'),
+      icon: (size: number) => <IconCodeOutline16 size={size} />,
       exts: [],
       priority: -100,
       fetchStrategy: 'fsRead',
@@ -74,6 +102,8 @@ export function builtinViewers(): readonly FileViewerDescriptor[] {
     },
     {
       id: 'binary-download',
+      title: () => t('viewerBinary'),
+      icon: (size: number) => <IconDownloadOutline16 size={size} />,
       exts: ['doc', 'xls', 'ppt'],
       priority: -50,
       fetchStrategy: 'binary-download',

src/client/icons.tsx

@@ -26,3 +26,60 @@ export const IconDiffOutline16 = ({ size = 16, className }: IconProps) => (
     <path d="M9.5 12.5h2.5" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" />
   </svg>
 )
+
+// ── File-viewer inventory glyphs (Side card settings page) ────────────────
+
+/** Image viewer glyph: a picture frame with a sun and a mountain. */
+export const IconImageOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <rect x="1.5" y="2.5" width="13" height="11" rx="2" stroke="currentColor" strokeWidth="1.5" />
+    <circle cx="5.5" cy="6" r="1.2" stroke="currentColor" strokeWidth="1.5" />
+    <path d="m3.5 12 3-3 2.25 2.25L11.5 8.5 13 10.5" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" />
+  </svg>
+)
+
+/** PDF viewer glyph: a document frame with the "PDF" label. */
+export const IconPdfOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <path d="M3.5 1.5h6.5L13.5 5v9.5h-10z" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" />
+    <path d="M9.5 1.5V5h4" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" />
+    <path d="M5 13.5v-3h1.4c.75 0 1.1.32 1.1.85 0 .54-.35.85-1.1.85H5.3" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" strokeLinejoin="round" />
+    <path d="M8.3 13.5v-3h1.05c.8 0 1.35.5 1.35 1.5s-.55 1.5-1.35 1.5z" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" strokeLinejoin="round" />
+    <path d="M11.6 13.5v-3h1.3" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" />
+  </svg>
+)
+
+/** Word viewer glyph: a document frame with a "W". */
+export const IconDocxOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <path d="M3.5 1.5h6.5L13.5 5v9.5h-10z" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" />
+    <path d="M9.5 1.5V5h4" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" />
+    <path d="M6.2 13.4 7.4 10l1.2 3.4M7.4 10.6l-.35-1.1c-.2-.62.2-1.25.85-1.25h.2c.65 0 1.05.63.85 1.25l-.35 1.1" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" strokeLinejoin="round" />
+    <path d="M8.75 10.6 9.2 9.4" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" />
+  </svg>
+)
+
+/** Excel viewer glyph: a spreadsheet grid. */
+export const IconXlsxOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <rect x="1.5" y="2" width="13" height="12" rx="2" stroke="currentColor" strokeWidth="1.5" />
+    <path d="M1.5 6h13M1.5 9.5h13M6 6v8M10.5 6v8" stroke="currentColor" strokeWidth="1.25" />
+    <path d="m3.8 13.2 2-3M5.8 13.2l-2-3" stroke="currentColor" strokeWidth="1.25" strokeLinecap="round" />
+  </svg>
+)
+
+/** PowerPoint viewer glyph: a chart with rising bars. */
+export const IconPptxOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <rect x="1.5" y="2.5" width="13" height="11" rx="2" stroke="currentColor" strokeWidth="1.5" />
+    <path d="M4 12.5v-3M7 12.5V7M10 12.5V4.5M13 12.5v-1.5" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" />
+  </svg>
+)
+
+/** Markdown viewer glyph: the classic "M with a down arrow" badge. */
+export const IconMarkdownOutline16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+    <rect x="1.5" y="2.5" width="13" height="11" rx="2" stroke="currentColor" strokeWidth="1.5" />
+    <path d="M4 10.5V5.5l2 2.5 2-2.5v5M9.5 10.5v-5l2 2.5 2-2.5v5" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round" />
+  </svg>
+)

src/client/index.tsx

@@ -149,13 +149,14 @@ export function apply(ctx: Context): void {
     // The "Side card" settings section: appears in the DSH Settings shell
     // once the shell's declaration is on the ledger (slots.inject waits for
     // it); the section reads/writes the prefs through the plugin's own
-    // fenced settings route and keeps the shared store in sync.
+    // fenced settings route, keeps the shared store in sync, and renders the
+    // declarative enable/disable inventory from the tab/viewer registry.
     ctx.slots.inject('settings.section', () => ctx.slots.register({
       name: 'settings.section',
       id: 'better-sidebar',
       order: 100,
       label: () => t('settingsNav'),
-      inject: () => ({ store: sidebarStore }),
+      inject: () => ({ store: sidebarStore, service }),
     }, SideCardSection))
   } catch (error) {
     fail('load', error)

src/client/intercept.tsx

@@ -60,7 +60,13 @@ export function SidebarProducedFiles(props: {
 export function registerTurnTailInterception(ctx: Context, store: SidebarStore): () => void {
   return ctx.slots.register({
     name: 'conversation.chat.turnTail',
-    select: selectProducedFiles,
+    // Decline the takeover while the editor tab type is disabled in the side
+    // card settings: the produced-files row falls back to the default
+    // deliverables behavior instead of offering chips that cannot open.
+    select: (owner) => {
+      if (store.getPrefs().tabsEnabled['editor'] === false) return null
+      return selectProducedFiles(owner)
+    },
     priority: -1,
     registrant: 'dsh-better-sidebar',
     inject: (sessionId: string) => ({

src/client/locales.ts

@@ -121,6 +121,17 @@ const zh = {
   settingsSubagentDesc: '当前会话产生新的子代理时，自动展开侧边栏并打开子代理页面；关闭后需手动打开',
   settingsToolsTitle: '为模型注入终端工具',
   settingsToolsDesc: '开启后，模型可通过 terminal_create 等 8 个工具创建并操作侧边栏终端（默认关闭）',
+  settingsTabsTitle: '侧边栏内容',
+  settingsViewersTitle: '文件预览',
+  settingsViewerCatchAll: '兜底：任意文件',
+  viewerImage: '图片',
+  viewerPdf: 'PDF',
+  viewerDocx: 'Word 文档',
+  viewerXlsx: 'Excel 表格',
+  viewerPptx: 'PPT 演示',
+  viewerMarkdown: 'Markdown',
+  viewerCode: '代码',
+  viewerBinary: '二进制下载',
   subagent: '子代理',
   openSubagent: '子代理',
   subagentMainAgent: '主代理',
@@ -254,6 +265,17 @@ const en: Record<keyof typeof zh, string> = {
   settingsSubagentDesc: 'Expand the side card and open the Subagent page when the current conversation spawns a new subagent; turn off to open it manually',
   settingsToolsTitle: 'Inject terminal tools for the model',
   settingsToolsDesc: 'When enabled, the model can create and drive sidebar terminals through the 8 terminal_* tools (off by default)',
+  settingsTabsTitle: 'Sidebar content',
+  settingsViewersTitle: 'File viewers',
+  settingsViewerCatchAll: 'Catch-all: any file',
+  viewerImage: 'Image',
+  viewerPdf: 'PDF',
+  viewerDocx: 'Word',
+  viewerXlsx: 'Excel',
+  viewerPptx: 'PowerPoint',
+  viewerMarkdown: 'Markdown',
+  viewerCode: 'Code',
+  viewerBinary: 'Binary download',
   subagent: 'Subagents',
   openSubagent: 'Subagents',
   subagentMainAgent: 'Main agent',

src/client/prefs.ts

@@ -21,8 +21,7 @@ export type { SidebarPrefs }
 /** The settings wire face the preferences need (a subset of the plugin api). */
 export type SidebarSettingsClient = Pick<typeof api, 'settingsGet' | 'settingsUpdate'>
 
-/**
- * Validate one raw resolved value into {@link SidebarPrefs}. Used for the
+/** Validate one raw resolved value into {@link SidebarPrefs}. Used for the
  * settings.get payload AND the settings.update response (both carry the
  * layered resolved value); any malformed field falls back to its default.
  * @param value - the raw resolved section from the settings wire.
@@ -44,9 +43,25 @@ export function parsePrefs(value: unknown): SidebarPrefs {
     agentTerminalTools: typeof record.agentTerminalTools === 'boolean'
       ? record.agentTerminalTools
       : SIDEBAR_PREFS_DEFAULTS.agentTerminalTools,
+    tabsEnabled: booleanMapOf(record.tabsEnabled),
+    viewersEnabled: booleanMapOf(record.viewersEnabled),
   }
 }
 
+/**
+ * Validate one enable-switch map (per-tab / per-viewer). Only boolean values
+ * survive; a non-object or a non-boolean entry falls back to the empty map /
+ * drops the entry — an absent key means the feature stays enabled.
+ */
+function booleanMapOf(value: unknown): Record<string, boolean> {
+  if (value === null || typeof value !== 'object' || Array.isArray(value)) return {}
+  const out: Record<string, boolean> = {}
+  for (const [key, item] of Object.entries(value as Record<string, unknown>)) {
+    if (typeof item === 'boolean') out[key] = item
+  }
+  return out
+}
+
 /**
  * Read the resolved side card preferences through the plugin's settings route.
  * @param settings - the settings wire face (the plugin api by default).

src/client/service.ts

@@ -27,6 +27,29 @@ import {
 } from './state.ts'
 import type { SessionScope } from './api.ts'
 
+/** One declarative boolean setting of a tab/viewer, rendered as a nested
+ *  switch row in the Side card settings page (e.g. the Subagent page's
+ *  "auto-open when a subagent appears"). */
+export interface SidebarSettingToggle {
+  /** The SidebarPrefs field this toggle reads and writes ('autoOpenSubagent'). */
+  key: string
+  /** Row title (i18n friendly: string or () => string). */
+  title: string | (() => string)
+  /** Row description (i18n friendly). */
+  desc?: string | (() => string)
+}
+
+/** Declarative settings of one registered tab or file viewer. */
+export interface SidebarSettingsDeclaration {
+  /**
+   * Extra boolean toggles rendered under the feature's own row in the
+   * settings page (only while the feature is enabled). Keys must be fields
+   * of the host's PrefsSchema (built-ins: 'autoOpenSubagent',
+   * 'agentTerminalTools'); unknown keys are dropped by the settings seam.
+   */
+  toggles?: readonly SidebarSettingToggle[]
+}
+
 /** Props every tab component receives (builtins and external alike). */
 export interface TabComponentProps {
   ctx: Context
@@ -81,6 +104,13 @@ export interface TabDescriptor {
    * When omitted, a default `{ id, type, title }` tab is created.
    */
   createTab?: (state: SidebarState) => { tab: SidebarTab; patch?: Partial<SidebarState> } | null
+  /**
+   * Declarative settings shown in the Side card settings page: every
+   * registered tab gets an enable/disable switch (icon + title + id), and
+   * `settings.toggles` adds nested switches tied to SidebarPrefs fields
+   * (e.g. the subagent tab's 'autoOpenSubagent').
+   */
+  settings?: SidebarSettingsDeclaration
   component: (props: TabComponentProps) => ReactNode
 }
 
@@ -114,6 +144,10 @@ export interface FileViewerProps {
 export interface FileViewerDescriptor {
   /** Unique id (`'image'`, `'pdf'`, `'my-plugin:csv'`). */
   id: string
+  /** Display name for the settings inventory (falls back to `id` when absent). */
+  title?: string | (() => string)
+  /** Icon shown in the settings inventory. */
+  icon?: ReactNode | ((size: number) => ReactNode)
   /** Lowercase extensions without leading dot (`['png','jpg']`). `[]` = match any (catch-all). */
   exts: readonly string[]
   /** Higher wins; default 0. Builtins use 0; the catch-all `code` viewer uses -100. */
@@ -126,6 +160,11 @@ export interface FileViewerDescriptor {
   detect?: (path: string, head: Uint8Array) => boolean
   /** fetchStrategy='custom' loader. */
   load?: (path: string, scope: SessionScope) => Promise<unknown>
+  /**
+   * Declarative settings shown in the Side card settings page: every
+   * registered viewer gets an enable/disable switch (icon + title + exts).
+   */
+  settings?: SidebarSettingsDeclaration
   component: (props: FileViewerProps) => ReactNode
 }
 
@@ -137,13 +176,25 @@ export interface BetterSidebarService {
   getFileViewers(): readonly FileViewerDescriptor[]
   /** Find a tab descriptor by id (undefined if not registered). */
   getTab(id: string): TabDescriptor | undefined
-  /** Find a file viewer for a path (priority desc; detect first, then exts). */
+  /**
+   * Whether a tab type is enabled in the side card prefs. An absent
+   * `tabsEnabled[id]` entry means enabled — only an explicit `false`
+   * disables the type (hidden from the + menu, `openTab` refuses, and
+   * derived flows gate on it).
+   */
+  isTabEnabled(id: string): boolean
+  /** Whether a file viewer is enabled (absent `viewersEnabled[id]` = enabled). */
+  isViewerEnabled(id: string): boolean
+  /**
+   * Find a file viewer for a path (priority desc; detect first, then exts).
+   * Disabled viewers are skipped, so files fall through to the next match.
+   */
   matchFileViewer(path: string, head?: Uint8Array): FileViewerDescriptor | undefined
   /**
    * Open a tab (used by external tabs and the + menu). `title` overrides
    * the descriptor's title when given (the editor tab shows the file name);
    * when the descriptor provides `createTab` it mints the tab itself and
-   * `title`/`path`/`id` are ignored.
+   * `title`/`path`/`id` are ignored. A disabled tab type is a no-op.
    */
   openTab(seed: { type: string; title?: string; path?: string; diff?: SidebarTab['diff']; id?: string }): void
   /** Close a tab by id. */
@@ -211,6 +262,11 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
   const getFileViewers = (): readonly FileViewerDescriptor[] => Array.from(viewers.values())
   const getTab = (id: string): TabDescriptor | undefined => tabs.get(id)
 
+  // The enable switches come from the user's side card prefs (the shared
+  // store the service is bound to): an absent key means enabled.
+  const isTabEnabled = (id: string): boolean => store.getPrefs().tabsEnabled[id] !== false
+  const isViewerEnabled = (id: string): boolean => store.getPrefs().viewersEnabled[id] !== false
+
   const matchFileViewer = (path: string, head?: Uint8Array): FileViewerDescriptor | undefined => {
     const ext = extOfPath(path)
     // Single pass in priority order (descending; stable for equal
@@ -218,10 +274,11 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
     // its own turn: `detect` (when head bytes are available) beats its own
     // `exts`, and `exts: []` is a catch-all matching any path — so the
     // catch-all `code` viewer (-100) only sees paths no higher-priority
-    // descriptor claimed.
+    // descriptor claimed. Disabled viewers are skipped entirely.
     for (const v of Array.from(viewers.values()).sort(
       (a, b) => (b.priority ?? 0) - (a.priority ?? 0),
     )) {
+      if (!isViewerEnabled(v.id)) continue
       // Content sniff first (only when head bytes are available).
       if (head !== undefined && v.detect !== undefined) {
         if (v.detect(path, head)) return v
@@ -241,6 +298,13 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
   }
 
   const openTab = (seed: { type: string; title?: string; path?: string; diff?: SidebarTab['diff']; id?: string }): void => {
+    // A type the user disabled in settings never opens — neither from the
+    // + menu nor from derived flows (file opens, subagent auto-open,
+    // external plugins). Already-open tabs keep rendering.
+    if (!isTabEnabled(seed.type)) {
+      console.warn(`[dsh-better-sidebar] tab type "${seed.type}" is disabled in the side card settings`)
+      return
+    }
     store.reduce((state) => {
       const descriptor = tabs.get(seed.type)
       if (descriptor === undefined) return state
@@ -278,6 +342,8 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
     getTabs,
     getFileViewers,
     getTab,
+    isTabEnabled,
+    isViewerEnabled,
     matchFileViewer,
     openTab,
     closeTab,

src/client/state.ts

@@ -114,11 +114,16 @@ function maxCounterId(parsed: unknown): number {
 /** A fresh default state: one explorer tab in one pane, open per the caller's
  * preference. `width` is the caller's preferred panel width (default
  * PANEL_DEFAULT) and `panelOpen` whether the panel starts expanded (default
- * true); the store seeds new sessions from the user's side card prefs. */
-export function makeDefaultState(width = PANEL_DEFAULT, panelOpen = true): SidebarState {
+ * true); the store seeds new sessions from the user's side card prefs.
+ * `seedExplorer` places the default explorer tab — the store passes false
+ * when the user disabled the explorer tab type in settings, so a fresh
+ * session starts with an empty pane instead of a tab they turned off. */
+export function makeDefaultState(width = PANEL_DEFAULT, panelOpen = true, seedExplorer = true): SidebarState {
   const leaf: SidebarLeaf = { kind: 'leaf', id: uid('pane'), tabs: [], active: null }
-  leaf.tabs = [{ id: uid('tab'), type: 'explorer', title: 'Explorer' }]
-  leaf.active = leaf.tabs[0]!.id
+  if (seedExplorer) {
+    leaf.tabs = [{ id: uid('tab'), type: 'explorer', title: 'Explorer' }]
+    leaf.active = leaf.tabs[0]!.id
+  }
   return {
     panelOpen,
     width,
@@ -510,6 +515,12 @@ const STORAGE_PREFIX = 'dsh-sidebar:v1'
 export interface SidebarSnapshot {
   sessionId: string | undefined
   state: SidebarState | undefined
+  /**
+   * The current side card prefs. Carried IN the snapshot (not a separate
+   * subscription) so prefs changes re-render the consumers that gate on
+   * them — the + menu hides a tab type the moment its switch flips.
+   */
+  prefs: SidebarPrefs
 }
 
 /** Default panel width for one viewport: the prefs percent of the window,
@@ -535,13 +546,14 @@ function loadState(sessionId: string, prefs: SidebarPrefs): SidebarState {
   }
   // New sessions seed from the user's side card prefs: the width is the
   // chosen percent of the window (clamped to the panel floor and the
-  // viewport so a huge percent can never crush the app shell), and the
-  // panel starts open only when the preference says so.
+  // viewport so a huge percent can never crush the app shell), the panel
+  // starts open only when the preference says so, and the default explorer
+  // tab is skipped when the user disabled the explorer tab type.
   const viewport = typeof window !== 'undefined' ? window.innerWidth : undefined
   const width = viewport === undefined
     ? PANEL_DEFAULT
     : defaultWidthFor(viewport, prefs.defaultWidthPercent)
-  return makeDefaultState(width, prefs.openByDefault)
+  return makeDefaultState(width, prefs.openByDefault, prefs.tabsEnabled['explorer'] !== false)
 }
 
 /**
@@ -659,15 +671,26 @@ function sanitizeNode(node: unknown, seen: Set<string>, reid: Map<string, string
 /** The session-scoped store: one state per conversation, localStorage-backed. */
 export class SidebarStore {
   private readonly bySession = new Map<string, SidebarState>()
-  private snapshot: SidebarSnapshot = { sessionId: undefined, state: undefined }
+  private snapshot: SidebarSnapshot = {
+    sessionId: undefined,
+    state: undefined,
+    prefs: { ...SIDEBAR_PREFS_DEFAULTS },
+  }
   private readonly listeners = new Set<() => void>()
   private persistTimer: number | undefined
   /** User-facing side card prefs seeding brand-new session states (defaults until the settings RPC resolves). */
   private prefs: SidebarPrefs = { ...SIDEBAR_PREFS_DEFAULTS }
 
-  /** Replace the side card prefs (the settings RPC result / settings page write). */
+  /**
+   * Replace the side card prefs (the settings RPC result / settings page
+   * write). Notifies like any store change: the snapshot carries the prefs,
+   * so consumers that gate on enable switches (the + menu, derived flows)
+   * re-render with the new values immediately.
+   */
   setPrefs(prefs: SidebarPrefs): void {
     this.prefs = { ...prefs }
+    this.snapshot = { ...this.snapshot, prefs: this.prefs }
+    this.notify()
   }
 
   /** The current side card prefs (seeds new sessions; persisted states win). */
@@ -679,7 +702,7 @@ export class SidebarStore {
   setSession(sessionId: string | undefined): void {
     if (this.snapshot.sessionId === sessionId) return
     if (sessionId === undefined) {
-      this.snapshot = { sessionId: undefined, state: undefined }
+      this.snapshot = { sessionId: undefined, state: undefined, prefs: this.prefs }
     } else {
       let state = this.bySession.get(sessionId)
       if (state === undefined) {
@@ -691,7 +714,7 @@ export class SidebarStore {
         // pane/split ids can never collide with its tree.
         nextIdCounter = maxCounterId(state)
       }
-      this.snapshot = { sessionId, state }
+      this.snapshot = { sessionId, state, prefs: this.prefs }
     }
     this.notify()
   }
@@ -713,7 +736,7 @@ export class SidebarStore {
     const draft = structuredClone(state)
     mutator(draft)
     this.bySession.set(sessionId, draft)
-    this.snapshot = { sessionId, state: draft }
+    this.snapshot = { sessionId, state: draft, prefs: this.prefs }
     this.schedulePersist(sessionId, draft)
     this.notify()
   }
@@ -740,7 +763,7 @@ export class SidebarStore {
     if (sessionId === undefined || state === undefined) return
     const next = reducer(state)
     this.bySession.set(sessionId, next)
-    this.snapshot = { sessionId, state: next }
+    this.snapshot = { sessionId, state: next, prefs: this.prefs }
     this.schedulePersist(sessionId, next)
     this.notify()
   }

src/config.ts

@@ -80,4 +80,9 @@ export const PrefsSchema: z<SidebarPrefs> = z.object({
   defaultWidthPercent: z.number().step(1).min(WIDTH_PERCENT_MIN).max(WIDTH_PERCENT_MAX).default(WIDTH_PERCENT_DEFAULT),
   autoOpenSubagent: z.boolean().default(true),
   agentTerminalTools: z.boolean().default(false),
+  // Per-feature enable switches are OPEN maps (any tab/viewer id, built-in or
+  // external): an absent key means enabled, so old documents resolve to {}
+  // (everything on) with no migration. Non-boolean values fail validation.
+  tabsEnabled: z.dict(z.boolean()).default({}),
+  viewersEnabled: z.dict(z.boolean()).default({}),
 })

src/prefs-shared.ts

@@ -27,6 +27,23 @@ export interface SidebarPrefs {
    * user explicitly enables it in the side card settings.
    */
   agentTerminalTools: boolean
+  /**
+   * Per-tab enable switches, keyed by tab descriptor id (`'explorer'`,
+   * `'my-plugin:db'`). An ABSENT key means enabled — only an explicit
+   * `false` disables a tab type (hidden from the + menu, `openTab` refuses,
+   * and derived flows like subagent auto-open / agent-terminal tabs stop).
+   * Already-open tabs of a disabled type keep rendering (closing one
+   * prevents reopening), matching the "existing conversations keep their
+   * own layouts" rule.
+   */
+  tabsEnabled: Record<string, boolean>
+  /**
+   * Per-viewer enable switches, keyed by file viewer descriptor id
+   * (`'image'`, `'my-plugin:csv'`). An ABSENT key means enabled; a disabled
+   * viewer is skipped by `matchFileViewer` so files fall through to the
+   * next matching viewer (or the download button when none match).
+   */
+  viewersEnabled: Record<string, boolean>
 }
 
 /** Range contract of {@link SidebarPrefs.defaultWidthPercent}. */
@@ -40,6 +57,8 @@ export const SIDEBAR_PREFS_DEFAULTS: SidebarPrefs = {
   defaultWidthPercent: WIDTH_PERCENT_DEFAULT,
   autoOpenSubagent: true,
   agentTerminalTools: false,
+  tabsEnabled: {},
+  viewersEnabled: {},
 }
 
 /** Clamp one width percent into the contract range (shared by schema and client reads). */