diff --git a/packages/desktop/src-tauri/src/commands/settings.rs b/packages/desktop/src-tauri/src/commands/settings.rs
index d8167d1e..0bfb2c4c 100644
--- a/packages/desktop/src-tauri/src/commands/settings.rs
+++ b/packages/desktop/src-tauri/src/commands/settings.rs
@@ -136,6 +136,21 @@ fn sanitize_settings_update(payload: &Value) -> Value {
         if let Some(Value::Bool(b)) = obj.get("showReasoningTraces") {
             result_obj.insert("showReasoningTraces".to_string(), json!(b));
         }
+        if let Some(Value::Bool(b)) = obj.get("autoDeleteEnabled") {
+            result_obj.insert("autoDeleteEnabled".to_string(), json!(b));
+        }
+
+        // Number fields
+        if let Some(Value::Number(n)) = obj.get("autoDeleteAfterDays") {
+            let parsed = n
+                .as_u64()
+                .or_else(|| n.as_i64().and_then(|value| if value >= 0 { Some(value as u64) } else { None }))
+                .or_else(|| n.as_f64().map(|value| value.round().max(0.0) as u64));
+            if let Some(value) = parsed {
+                let clamped = value.max(1).min(365);
+                result_obj.insert("autoDeleteAfterDays".to_string(), json!(clamped));
+            }
+        }
 
         // Array fields
         if let Some(arr) = obj.get("approvedDirectories") {
diff --git a/packages/ui/src/App.tsx b/packages/ui/src/App.tsx
index 15832a84..4e77adcb 100644
--- a/packages/ui/src/App.tsx
+++ b/packages/ui/src/App.tsx
@@ -10,6 +10,7 @@ import { useKeyboardShortcuts } from '@/hooks/useKeyboardShortcuts';
 import { useMenuActions } from '@/hooks/useMenuActions';
 import { useMessageSync } from '@/hooks/useMessageSync';
 import { useSessionStatusBootstrap } from '@/hooks/useSessionStatusBootstrap';
+import { useSessionAutoCleanup } from '@/hooks/useSessionAutoCleanup';
 import { GitPollingProvider } from '@/hooks/useGitPolling';
 import { useConfigStore } from '@/stores/useConfigStore';
 import { useSessionStore } from '@/stores/useSessionStore';
@@ -152,6 +153,7 @@ function App({ apis }: AppProps) {
   useMessageSync();
 
   useSessionStatusBootstrap();
+  useSessionAutoCleanup();
 
   React.useEffect(() => {
     const handleKeyDown = (e: KeyboardEvent) => {
diff --git a/packages/ui/src/components/sections/settings/SessionRetentionSettings.tsx b/packages/ui/src/components/sections/settings/SessionRetentionSettings.tsx
new file mode 100644
index 00000000..884f8a18
--- /dev/null
+++ b/packages/ui/src/components/sections/settings/SessionRetentionSettings.tsx
@@ -0,0 +1,136 @@
+import React from 'react';
+import { toast } from 'sonner';
+import { RiInformationLine } from '@remixicon/react';
+import { NumberInput } from '@/components/ui/number-input';
+import { ButtonSmall } from '@/components/ui/button-small';
+import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip';
+import { useDeviceInfo } from '@/lib/device';
+import { useUIStore } from '@/stores/useUIStore';
+import { useSessionAutoCleanup } from '@/hooks/useSessionAutoCleanup';
+
+const MIN_DAYS = 1;
+const MAX_DAYS = 365;
+
+export const SessionRetentionSettings: React.FC = () => {
+  const { isMobile } = useDeviceInfo();
+  const autoDeleteEnabled = useUIStore((state) => state.autoDeleteEnabled);
+  const autoDeleteAfterDays = useUIStore((state) => state.autoDeleteAfterDays);
+  const setAutoDeleteEnabled = useUIStore((state) => state.setAutoDeleteEnabled);
+  const setAutoDeleteAfterDays = useUIStore((state) => state.setAutoDeleteAfterDays);
+
+  const [mobileDraftDays, setMobileDraftDays] = React.useState(String(autoDeleteAfterDays));
+
+  React.useEffect(() => {
+    setMobileDraftDays(String(autoDeleteAfterDays));
+  }, [autoDeleteAfterDays]);
+
+  const { candidates, isRunning, runCleanup, keepRecentCount } = useSessionAutoCleanup({ autoRun: false });
+  const pendingCount = candidates.length;
+
+  const handleRunCleanup = React.useCallback(async () => {
+    const result = await runCleanup({ force: true });
+    if (result.deletedIds.length === 0 && result.failedIds.length === 0) {
+      toast.message('No sessions eligible for deletion');
+      return;
+    }
+    if (result.deletedIds.length > 0) {
+      toast.success(`Deleted ${result.deletedIds.length} session${result.deletedIds.length === 1 ? '' : 's'}`);
+    }
+    if (result.failedIds.length > 0) {
+      toast.error(`Failed to delete ${result.failedIds.length} session${result.failedIds.length === 1 ? '' : 's'}`);
+    }
+  }, [runCleanup]);
+
+  return (
+    <div className="space-y-4">
+      <div className="space-y-1">
+        <div className="flex items-center gap-2">
+          <h3 className="typography-ui-header font-semibold text-foreground">Session retention</h3>
+          <Tooltip delayDuration={1000}>
+            <TooltipTrigger asChild>
+              <RiInformationLine className="h-3.5 w-3.5 text-muted-foreground/60 cursor-help" />
+            </TooltipTrigger>
+            <TooltipContent sideOffset={8} className="max-w-xs">
+              Automatically delete inactive sessions based on their last activity.<br />
+              You can also run a one-time cleanup without enabling auto-cleanup.<br />
+              Keeps the most recent 5 sessions, and never deletes shared sessions.
+            </TooltipContent>
+          </Tooltip>
+        </div>
+      </div>
+
+      <label className="flex items-center gap-2 cursor-pointer">
+        <input
+          type="checkbox"
+          className="h-3.5 w-3.5 accent-primary"
+          checked={autoDeleteEnabled}
+          onChange={(event) => setAutoDeleteEnabled(event.target.checked)}
+        />
+        <span className="typography-ui-header font-semibold text-foreground">Enable auto-cleanup</span>
+      </label>
+
+      <div className="flex flex-wrap items-center gap-3">
+        <div className="flex items-center gap-3">
+          {isMobile ? (
+            <input
+              type="number"
+              inputMode="numeric"
+              value={mobileDraftDays}
+              onChange={(event) => {
+                const nextValue = event.target.value;
+                setMobileDraftDays(nextValue);
+                if (nextValue.trim() === '') {
+                  return;
+                }
+                const parsed = Number(nextValue);
+                if (!Number.isFinite(parsed)) {
+                  return;
+                }
+                const clamped = Math.min(MAX_DAYS, Math.max(MIN_DAYS, Math.round(parsed)));
+                setAutoDeleteAfterDays(clamped);
+              }}
+              onBlur={() => {
+                if (mobileDraftDays.trim() === '') {
+                  setMobileDraftDays(String(autoDeleteAfterDays));
+                  return;
+                }
+                const parsed = Number(mobileDraftDays);
+                if (!Number.isFinite(parsed)) {
+                  setMobileDraftDays(String(autoDeleteAfterDays));
+                  return;
+                }
+                const clamped = Math.min(MAX_DAYS, Math.max(MIN_DAYS, Math.round(parsed)));
+                setAutoDeleteAfterDays(clamped);
+                setMobileDraftDays(String(clamped));
+              }}
+              aria-label="Retention period in days"
+              className="h-8 w-16 rounded-lg border border-border bg-background px-2 text-center typography-ui-label text-foreground focus:border-ring focus:outline-none focus:ring-2 focus:ring-ring/50"
+            />
+          ) : (
+            <NumberInput
+              value={autoDeleteAfterDays}
+              onValueChange={setAutoDeleteAfterDays}
+              min={MIN_DAYS}
+              max={MAX_DAYS}
+              step={1}
+              aria-label="Retention period in days"
+            />
+          )}
+          <span className="typography-ui-label text-muted-foreground">days since last activity</span>
+        </div>
+        <ButtonSmall
+          type="button"
+          variant="outline"
+          onClick={handleRunCleanup}
+          disabled={isRunning}
+        >
+          {isRunning ? 'Cleaning up...' : 'Run cleanup now'}
+        </ButtonSmall>
+      </div>
+
+      <div className="typography-meta text-muted-foreground">
+        Eligible for deletion right now: {pendingCount}
+      </div>
+    </div>
+  );
+};
diff --git a/packages/ui/src/components/sections/settings/SettingsPage.tsx b/packages/ui/src/components/sections/settings/SettingsPage.tsx
index 1f46b963..cced594c 100644
--- a/packages/ui/src/components/sections/settings/SettingsPage.tsx
+++ b/packages/ui/src/components/sections/settings/SettingsPage.tsx
@@ -1,6 +1,7 @@
 import React from 'react';
 import { AppearanceSettings } from './AppearanceSettings';
 import { AboutSettings } from './AboutSettings';
+import { SessionRetentionSettings } from './SessionRetentionSettings';
 import { ScrollableOverlay } from '@/components/ui/ScrollableOverlay';
 import { useDeviceInfo } from '@/lib/device';
 import { isWebRuntime } from '@/lib/desktop';
@@ -15,6 +16,9 @@ export const SettingsPage: React.FC = () => {
             className="settings-page-body mx-auto max-w-3xl space-y-3 p-3 sm:space-y-6 sm:p-6"
         >
             <AppearanceSettings />
+            <div className="border-t border-border/40 pt-6">
+                <SessionRetentionSettings />
+            </div>
             {showAbout && (
                 <div className="border-t border-border/40 pt-6">
                     <AboutSettings />
diff --git a/packages/ui/src/hooks/useSessionAutoCleanup.ts b/packages/ui/src/hooks/useSessionAutoCleanup.ts
new file mode 100644
index 00000000..41e131c9
--- /dev/null
+++ b/packages/ui/src/hooks/useSessionAutoCleanup.ts
@@ -0,0 +1,179 @@
+import React from 'react';
+import type { Session } from '@opencode-ai/sdk';
+import { useSessionStore } from '@/stores/useSessionStore';
+import { useUIStore } from '@/stores/useUIStore';
+
+const DAY_MS = 24 * 60 * 60 * 1000;
+const AUTO_DELETE_KEEP_RECENT = 5;
+const AUTO_DELETE_INTERVAL_MS = 24 * 60 * 60 * 1000;
+
+const getSessionLastActivity = (session: Session): number => {
+  return session.time?.updated ?? session.time?.created ?? 0;
+};
+
+type BuildAutoDeleteCandidatesOptions = {
+  sessions: Session[];
+  currentSessionId: string | null;
+  cutoffDays: number;
+  keepRecent?: number;
+  now?: number;
+};
+
+export const buildAutoDeleteCandidates = ({
+  sessions,
+  currentSessionId,
+  cutoffDays,
+  keepRecent = AUTO_DELETE_KEEP_RECENT,
+  now = Date.now(),
+}: BuildAutoDeleteCandidatesOptions): string[] => {
+  if (!Array.isArray(sessions) || cutoffDays <= 0) {
+    return [];
+  }
+
+  const cutoffTime = now - cutoffDays * DAY_MS;
+  const sorted = [...sessions].sort(
+    (a, b) => getSessionLastActivity(b) - getSessionLastActivity(a)
+  );
+  const protectedIds = new Set(sorted.slice(0, keepRecent).map((session) => session.id));
+
+  return sorted
+    .filter((session) => {
+      if (!session?.id) return false;
+      if (protectedIds.has(session.id)) return false;
+      if (session.id === currentSessionId) return false;
+      if (session.share) return false;
+      const lastActivity = getSessionLastActivity(session);
+      if (!lastActivity) return false;
+      return lastActivity < cutoffTime;
+    })
+    .map((session) => session.id);
+};
+
+type CleanupResult = {
+  deletedIds: string[];
+  failedIds: string[];
+  skippedReason?: 'disabled' | 'loading' | 'cooldown' | 'no-candidates' | 'running';
+};
+
+type CleanupOptions = {
+  autoRun?: boolean;
+};
+
+export const useSessionAutoCleanup = (options?: CleanupOptions) => {
+  const autoRun = options?.autoRun !== false;
+
+  const sessions = useSessionStore((state) => state.sessions);
+  const currentSessionId = useSessionStore((state) => state.currentSessionId);
+  const isLoading = useSessionStore((state) => state.isLoading);
+  const deleteSessions = useSessionStore((state) => state.deleteSessions);
+
+  const autoDeleteEnabled = useUIStore((state) => state.autoDeleteEnabled);
+  const autoDeleteAfterDays = useUIStore((state) => state.autoDeleteAfterDays);
+  const autoDeleteLastRunAt = useUIStore((state) => state.autoDeleteLastRunAt);
+  const setAutoDeleteLastRunAt = useUIStore((state) => state.setAutoDeleteLastRunAt);
+
+  const [isRunning, setIsRunning] = React.useState(false);
+  const runningRef = React.useRef(false);
+
+  const candidates = React.useMemo(() => {
+    if (autoDeleteAfterDays <= 0) {
+      return [];
+    }
+    return buildAutoDeleteCandidates({
+      sessions,
+      currentSessionId,
+      cutoffDays: autoDeleteAfterDays,
+    });
+  }, [autoDeleteAfterDays, currentSessionId, sessions]);
+
+  const runCleanup = React.useCallback(
+    async ({ force = false }: { force?: boolean } = {}): Promise<CleanupResult> => {
+      if (runningRef.current) {
+        return { deletedIds: [], failedIds: [], skippedReason: 'running' };
+      }
+
+      if (!autoDeleteEnabled || autoDeleteAfterDays <= 0) {
+        if (!force) {
+          return { deletedIds: [], failedIds: [], skippedReason: 'disabled' };
+        }
+      }
+
+      if (isLoading) {
+        return { deletedIds: [], failedIds: [], skippedReason: 'loading' };
+      }
+
+      const now = Date.now();
+      if (!force && autoDeleteLastRunAt && now - autoDeleteLastRunAt < AUTO_DELETE_INTERVAL_MS) {
+        return { deletedIds: [], failedIds: [], skippedReason: 'cooldown' };
+      }
+
+      if (sessions.length === 0) {
+        return { deletedIds: [], failedIds: [], skippedReason: 'no-candidates' };
+      }
+
+      const candidateIds = buildAutoDeleteCandidates({
+        sessions,
+        currentSessionId,
+        cutoffDays: autoDeleteAfterDays,
+        now,
+      });
+
+      if (candidateIds.length === 0) {
+        setAutoDeleteLastRunAt(now);
+        return { deletedIds: [], failedIds: [], skippedReason: 'no-candidates' };
+      }
+
+      runningRef.current = true;
+      setIsRunning(true);
+      try {
+        const result = await deleteSessions(candidateIds, { silent: true });
+        return result;
+      } finally {
+        runningRef.current = false;
+        setIsRunning(false);
+        setAutoDeleteLastRunAt(Date.now());
+      }
+    },
+    [
+      autoDeleteAfterDays,
+      autoDeleteEnabled,
+      autoDeleteLastRunAt,
+      currentSessionId,
+      deleteSessions,
+      isLoading,
+      sessions,
+      setAutoDeleteLastRunAt,
+    ]
+  );
+
+  React.useEffect(() => {
+    if (!autoRun) {
+      return;
+    }
+    if (!autoDeleteEnabled || autoDeleteAfterDays <= 0) {
+      return;
+    }
+    if (isLoading || sessions.length === 0) {
+      return;
+    }
+    const now = Date.now();
+    if (autoDeleteLastRunAt && now - autoDeleteLastRunAt < AUTO_DELETE_INTERVAL_MS) {
+      return;
+    }
+    void runCleanup();
+  }, [
+    autoDeleteAfterDays,
+    autoDeleteEnabled,
+    autoDeleteLastRunAt,
+    autoRun,
+    isLoading,
+    runCleanup,
+  ]);
+
+  return {
+    candidates,
+    isRunning,
+    runCleanup,
+    keepRecentCount: AUTO_DELETE_KEEP_RECENT,
+  };
+};
diff --git a/packages/ui/src/lib/api/types.ts b/packages/ui/src/lib/api/types.ts
index ca938c97..0f520976 100644
--- a/packages/ui/src/lib/api/types.ts
+++ b/packages/ui/src/lib/api/types.ts
@@ -330,6 +330,8 @@ export interface SettingsPayload {
   securityScopedBookmarks?: string[];
   pinnedDirectories?: string[];
   showReasoningTraces?: boolean;
+  autoDeleteEnabled?: boolean;
+  autoDeleteAfterDays?: number;
 
   [key: string]: unknown;
 }
diff --git a/packages/ui/src/lib/appearanceAutoSave.ts b/packages/ui/src/lib/appearanceAutoSave.ts
index 23ce4a2e..6ac79ad7 100644
--- a/packages/ui/src/lib/appearanceAutoSave.ts
+++ b/packages/ui/src/lib/appearanceAutoSave.ts
@@ -4,6 +4,8 @@ import type { DesktopSettings } from '@/lib/desktop';
 
 type AppearanceSlice = {
   showReasoningTraces: boolean;
+  autoDeleteEnabled: boolean;
+  autoDeleteAfterDays: number;
 };
 
 let initialized = false;
@@ -17,6 +19,8 @@ export const startAppearanceAutoSave = (): void => {
 
   let previous: AppearanceSlice = {
     showReasoningTraces: useUIStore.getState().showReasoningTraces,
+    autoDeleteEnabled: useUIStore.getState().autoDeleteEnabled,
+    autoDeleteAfterDays: useUIStore.getState().autoDeleteAfterDays,
   };
 
   let pending: Partial<DesktopSettings> | null = null;
@@ -42,6 +46,8 @@ export const startAppearanceAutoSave = (): void => {
   useUIStore.subscribe((state) => {
     const current: AppearanceSlice = {
       showReasoningTraces: state.showReasoningTraces,
+      autoDeleteEnabled: state.autoDeleteEnabled,
+      autoDeleteAfterDays: state.autoDeleteAfterDays,
     };
 
     const diff: Partial<DesktopSettings> = {};
@@ -49,6 +55,12 @@ export const startAppearanceAutoSave = (): void => {
     if (current.showReasoningTraces !== previous.showReasoningTraces) {
       diff.showReasoningTraces = current.showReasoningTraces;
     }
+    if (current.autoDeleteEnabled !== previous.autoDeleteEnabled) {
+      diff.autoDeleteEnabled = current.autoDeleteEnabled;
+    }
+    if (current.autoDeleteAfterDays !== previous.autoDeleteAfterDays) {
+      diff.autoDeleteAfterDays = current.autoDeleteAfterDays;
+    }
 
     previous = current;
 
diff --git a/packages/ui/src/lib/desktop.ts b/packages/ui/src/lib/desktop.ts
index 7616f254..b4d8751b 100644
--- a/packages/ui/src/lib/desktop.ts
+++ b/packages/ui/src/lib/desktop.ts
@@ -39,6 +39,8 @@ export type DesktopSettings = {
   securityScopedBookmarks?: string[];
   pinnedDirectories?: string[];
   showReasoningTraces?: boolean;
+  autoDeleteEnabled?: boolean;
+  autoDeleteAfterDays?: number;
 };
 
 export type DesktopSettingsApi = {
diff --git a/packages/ui/src/lib/persistence.ts b/packages/ui/src/lib/persistence.ts
index 7a5483f9..cbb83e9a 100644
--- a/packages/ui/src/lib/persistence.ts
+++ b/packages/ui/src/lib/persistence.ts
@@ -59,6 +59,15 @@ const applyDesktopUiPreferences = (settings: DesktopSettings) => {
   if (typeof settings.showReasoningTraces === 'boolean' && settings.showReasoningTraces !== store.showReasoningTraces) {
     store.setShowReasoningTraces(settings.showReasoningTraces);
   }
+  if (typeof settings.autoDeleteEnabled === 'boolean' && settings.autoDeleteEnabled !== store.autoDeleteEnabled) {
+    store.setAutoDeleteEnabled(settings.autoDeleteEnabled);
+  }
+  if (typeof settings.autoDeleteAfterDays === 'number' && Number.isFinite(settings.autoDeleteAfterDays)) {
+    const normalized = Math.max(1, Math.min(365, settings.autoDeleteAfterDays));
+    if (normalized !== store.autoDeleteAfterDays) {
+      store.setAutoDeleteAfterDays(normalized);
+    }
+  }
 };
 
 const sanitizeWebSettings = (payload: unknown): DesktopSettings | null => {
@@ -110,6 +119,12 @@ const sanitizeWebSettings = (payload: unknown): DesktopSettings | null => {
   if (typeof candidate.showReasoningTraces === 'boolean') {
     result.showReasoningTraces = candidate.showReasoningTraces;
   }
+  if (typeof candidate.autoDeleteEnabled === 'boolean') {
+    result.autoDeleteEnabled = candidate.autoDeleteEnabled;
+  }
+  if (typeof candidate.autoDeleteAfterDays === 'number' && Number.isFinite(candidate.autoDeleteAfterDays)) {
+    result.autoDeleteAfterDays = candidate.autoDeleteAfterDays;
+  }
 
   return result;
 };
diff --git a/packages/ui/src/stores/sessionStore.ts b/packages/ui/src/stores/sessionStore.ts
index 4bae2cef..a849b060 100644
--- a/packages/ui/src/stores/sessionStore.ts
+++ b/packages/ui/src/stores/sessionStore.ts
@@ -653,13 +653,19 @@ export const useSessionStore = create<SessionStore>()(
                     }
                 },
 
-                deleteSessions: async (ids: string[], options) => {
+                deleteSessions: async (
+                    ids: string[],
+                    options?: { archiveWorktree?: boolean; deleteRemoteBranch?: boolean; remoteName?: string; silent?: boolean }
+                ) => {
                     const uniqueIds = Array.from(new Set(ids.filter((id): id is string => typeof id === "string" && id.length > 0)));
                     if (uniqueIds.length === 0) {
                         return { deletedIds: [], failedIds: [] };
                     }
 
-                    set({ isLoading: true, error: null });
+                    const silent = options?.silent === true;
+                    if (!silent) {
+                        set({ isLoading: true, error: null });
+                    }
                     const deletedIds: string[] = [];
                     const failedIds: string[] = [];
                     const archivedIds = new Set<string>();
@@ -743,10 +749,9 @@ export const useSessionStore = create<SessionStore>()(
                         return {
                             sessions: filteredSessions,
                             currentSessionId: nextCurrentId,
-                            isLoading: false,
+                            ...(silent ? {} : { isLoading: false, error: errorMessage }),
                             worktreeMetadata: nextMetadata,
                             availableWorktrees: nextAvailableWorktrees,
-                            error: errorMessage,
                         };
                     });
 
diff --git a/packages/ui/src/stores/types/sessionTypes.ts b/packages/ui/src/stores/types/sessionTypes.ts
index 3e677f5e..37c3f9e5 100644
--- a/packages/ui/src/stores/types/sessionTypes.ts
+++ b/packages/ui/src/stores/types/sessionTypes.ts
@@ -104,7 +104,7 @@ export interface SessionStore {
     createSessionFromAssistantMessage: (sourceMessageId: string) => Promise<void>;
 
     deleteSession: (id: string, options?: { archiveWorktree?: boolean; deleteRemoteBranch?: boolean; remoteName?: string }) => Promise<boolean>;
-    deleteSessions: (ids: string[], options?: { archiveWorktree?: boolean; deleteRemoteBranch?: boolean; remoteName?: string }) => Promise<{ deletedIds: string[]; failedIds: string[] }>;
+    deleteSessions: (ids: string[], options?: { archiveWorktree?: boolean; deleteRemoteBranch?: boolean; remoteName?: string; silent?: boolean }) => Promise<{ deletedIds: string[]; failedIds: string[] }>;
     updateSessionTitle: (id: string, title: string) => Promise<void>;
     shareSession: (id: string) => Promise<Session | null>;
     unshareSession: (id: string) => Promise<Session | null>;
diff --git a/packages/ui/src/stores/useUIStore.ts b/packages/ui/src/stores/useUIStore.ts
index efdd4cf9..877d90ea 100644
--- a/packages/ui/src/stores/useUIStore.ts
+++ b/packages/ui/src/stores/useUIStore.ts
@@ -33,6 +33,9 @@ interface UIStore {
   eventStreamStatus: EventStreamStatus;
   eventStreamHint: string | null;
   showReasoningTraces: boolean;
+  autoDeleteEnabled: boolean;
+  autoDeleteAfterDays: number;
+  autoDeleteLastRunAt: number | null;
 
   toolCallExpansion: 'collapsed' | 'activity' | 'detailed';
   fontSize: number;
@@ -66,6 +69,9 @@ interface UIStore {
   setSidebarSection: (section: SidebarSection) => void;
   setEventStreamStatus: (status: EventStreamStatus, hint?: string | null) => void;
   setShowReasoningTraces: (value: boolean) => void;
+  setAutoDeleteEnabled: (value: boolean) => void;
+  setAutoDeleteAfterDays: (days: number) => void;
+  setAutoDeleteLastRunAt: (timestamp: number | null) => void;
   setToolCallExpansion: (value: 'collapsed' | 'activity' | 'detailed') => void;
   setFontSize: (size: number) => void;
   setPadding: (size: number) => void;
@@ -102,6 +108,9 @@ export const useUIStore = create<UIStore>()(
         eventStreamStatus: 'idle',
         eventStreamHint: null,
         showReasoningTraces: false,
+        autoDeleteEnabled: false,
+        autoDeleteAfterDays: 30,
+        autoDeleteLastRunAt: null,
         toolCallExpansion: 'collapsed',
         fontSize: 100,
         padding: 100,
@@ -222,6 +231,19 @@ export const useUIStore = create<UIStore>()(
           set({ showReasoningTraces: value });
         },
 
+        setAutoDeleteEnabled: (value) => {
+          set({ autoDeleteEnabled: value });
+        },
+
+        setAutoDeleteAfterDays: (days) => {
+          const clampedDays = Math.max(1, Math.min(365, days));
+          set({ autoDeleteAfterDays: clampedDays });
+        },
+
+        setAutoDeleteLastRunAt: (timestamp) => {
+          set({ autoDeleteLastRunAt: timestamp });
+        },
+
         setToolCallExpansion: (value) => {
           set({ toolCallExpansion: value });
         },
@@ -399,6 +421,9 @@ export const useUIStore = create<UIStore>()(
           isSessionCreateDialogOpen: state.isSessionCreateDialogOpen,
           isSettingsDialogOpen: state.isSettingsDialogOpen,
           showReasoningTraces: state.showReasoningTraces,
+          autoDeleteEnabled: state.autoDeleteEnabled,
+          autoDeleteAfterDays: state.autoDeleteAfterDays,
+          autoDeleteLastRunAt: state.autoDeleteLastRunAt,
           toolCallExpansion: state.toolCallExpansion,
           fontSize: state.fontSize,
           padding: state.padding,
diff --git a/packages/vscode/webview/stores/chatStore.ts b/packages/vscode/webview/stores/chatStore.ts
index eda72532..9a00d0cd 100644
--- a/packages/vscode/webview/stores/chatStore.ts
+++ b/packages/vscode/webview/stores/chatStore.ts
@@ -5,6 +5,65 @@ import type { Session, Message, Part } from '@opencode-ai/sdk';
 const getApiUrl = () => window.__VSCODE_CONFIG__?.apiUrl || 'http://localhost:47339';
 const getWorkspaceFolder = () => window.__VSCODE_CONFIG__?.workspaceFolder || '';
 
+const AUTO_DELETE_STORAGE_KEY = 'oc.vscode.autoDeleteLastRunAt';
+const AUTO_DELETE_DEFAULT_DAYS = 30;
+const AUTO_DELETE_KEEP_RECENT = 5;
+const AUTO_DELETE_INTERVAL_MS = 24 * 60 * 60 * 1000;
+
+let autoDeleteRunning = false;
+
+const getLastActivity = (session: Session): number => {
+  return session.time?.updated ?? session.time?.created ?? 0;
+};
+
+const readAutoDeleteLastRunAt = (): number | null => {
+  if (typeof window === 'undefined') return null;
+  try {
+    const value = window.localStorage.getItem(AUTO_DELETE_STORAGE_KEY);
+    if (!value) return null;
+    const parsed = Number(value);
+    return Number.isFinite(parsed) ? parsed : null;
+  } catch {
+    return null;
+  }
+};
+
+const writeAutoDeleteLastRunAt = (timestamp: number) => {
+  if (typeof window === 'undefined') return;
+  try {
+    window.localStorage.setItem(AUTO_DELETE_STORAGE_KEY, String(timestamp));
+  } catch {
+    // ignore storage errors
+  }
+};
+
+const buildAutoDeleteCandidates = (
+  sessions: Session[],
+  currentSessionId: string | null,
+  cutoffDays: number,
+  now = Date.now()
+): string[] => {
+  if (!Array.isArray(sessions) || cutoffDays <= 0) {
+    return [];
+  }
+
+  const cutoffTime = now - cutoffDays * 24 * 60 * 60 * 1000;
+  const sorted = [...sessions].sort((a, b) => getLastActivity(b) - getLastActivity(a));
+  const protectedIds = new Set(sorted.slice(0, AUTO_DELETE_KEEP_RECENT).map((session) => session.id));
+
+  return sorted
+    .filter((session) => {
+      if (!session?.id) return false;
+      if (protectedIds.has(session.id)) return false;
+      if (session.id === currentSessionId) return false;
+      if (session.share) return false;
+      const lastActivity = getLastActivity(session);
+      if (!lastActivity) return false;
+      return lastActivity < cutoffTime;
+    })
+    .map((session) => session.id);
+};
+
 interface MessageRecord {
   info: Message;
   parts: Part[];
@@ -19,6 +78,9 @@ interface ChatState {
   sessions: Session[];
   currentSessionId: string | null;
   isLoadingSessions: boolean;
+  autoDeleteEnabled: boolean;
+  autoDeleteAfterDays: number;
+  autoDeleteLastRunAt: number | null;
 
   // Messages
   messages: Map<string, MessageRecord[]>;
@@ -28,6 +90,8 @@ interface ChatState {
 
   // Actions
   initialize: () => Promise<void>;
+  loadAutoDeleteSettings: () => Promise<void>;
+  runAutoCleanup: (sessionsOverride?: Session[]) => Promise<void>;
   loadSessions: () => Promise<void>;
   createSession: () => Promise<string | null>;
   selectSession: (sessionId: string) => Promise<void>;
@@ -42,6 +106,9 @@ export const useChatStore = create<ChatState>((set, get) => ({
   sessions: [],
   currentSessionId: null,
   isLoadingSessions: false,
+  autoDeleteEnabled: false,
+  autoDeleteAfterDays: AUTO_DELETE_DEFAULT_DAYS,
+  autoDeleteLastRunAt: readAutoDeleteLastRunAt(),
   messages: new Map(),
   isLoadingMessages: false,
   isSending: false,
@@ -55,6 +122,7 @@ export const useChatStore = create<ChatState>((set, get) => ({
     try {
       await client.session.list({ query: { directory: getWorkspaceFolder() } });
       set({ client, isConnected: true });
+      await get().loadAutoDeleteSettings();
       await get().loadSessions();
     } catch (error) {
       console.error('Failed to connect to OpenCode API:', error);
@@ -62,6 +130,99 @@ export const useChatStore = create<ChatState>((set, get) => ({
     }
   },
 
+  loadAutoDeleteSettings: async () => {
+    try {
+      const response = await fetch('/api/config/settings', {
+        method: 'GET',
+        headers: { Accept: 'application/json' },
+      });
+
+      if (!response.ok) {
+        const lastRunAt = readAutoDeleteLastRunAt();
+        set({ autoDeleteLastRunAt: lastRunAt });
+        return;
+      }
+
+      const payload = await response.json().catch(() => ({}));
+      const enabled = typeof payload.autoDeleteEnabled === 'boolean' ? payload.autoDeleteEnabled : false;
+      const daysRaw = typeof payload.autoDeleteAfterDays === 'number'
+        ? payload.autoDeleteAfterDays
+        : Number(payload.autoDeleteAfterDays);
+      const normalizedDays = Number.isFinite(daysRaw)
+        ? Math.max(1, Math.min(365, daysRaw))
+        : AUTO_DELETE_DEFAULT_DAYS;
+      const lastRunAt = readAutoDeleteLastRunAt();
+
+      set({
+        autoDeleteEnabled: enabled,
+        autoDeleteAfterDays: normalizedDays,
+        autoDeleteLastRunAt: lastRunAt,
+      });
+    } catch {
+      const lastRunAt = readAutoDeleteLastRunAt();
+      set({ autoDeleteLastRunAt: lastRunAt });
+    }
+  },
+
+  runAutoCleanup: async (sessionsOverride) => {
+    const { client, autoDeleteEnabled, autoDeleteAfterDays, currentSessionId } = get();
+    if (!client || !autoDeleteEnabled || autoDeleteAfterDays <= 0) {
+      return;
+    }
+    if (autoDeleteRunning) {
+      return;
+    }
+
+    const now = Date.now();
+    const lastRunAt = readAutoDeleteLastRunAt();
+    if (lastRunAt && now - lastRunAt < AUTO_DELETE_INTERVAL_MS) {
+      set({ autoDeleteLastRunAt: lastRunAt });
+      return;
+    }
+
+    const sessions = sessionsOverride ?? get().sessions;
+    if (!sessions.length) {
+      return;
+    }
+
+    const candidateIds = buildAutoDeleteCandidates(sessions, currentSessionId, autoDeleteAfterDays, now);
+    if (candidateIds.length === 0) {
+      writeAutoDeleteLastRunAt(now);
+      set({ autoDeleteLastRunAt: now });
+      return;
+    }
+
+    autoDeleteRunning = true;
+    const deletedIds: string[] = [];
+
+    try {
+      for (const id of candidateIds) {
+        try {
+          const response = await client.session.delete({
+            path: { id },
+            query: { directory: getWorkspaceFolder() },
+          });
+          if (response.data) {
+            deletedIds.push(id);
+          }
+        } catch {
+          // ignore individual delete failures
+        }
+      }
+    } finally {
+      autoDeleteRunning = false;
+      const finishedAt = Date.now();
+      writeAutoDeleteLastRunAt(finishedAt);
+      set({ autoDeleteLastRunAt: finishedAt });
+    }
+
+    if (deletedIds.length > 0) {
+      set((state) => ({
+        sessions: state.sessions.filter((session) => !deletedIds.includes(session.id)),
+      }));
+    }
+  },
+
   loadSessions: async () => {
     const { client } = get();
     if (!client) return;
@@ -74,6 +235,7 @@ export const useChatStore = create<ChatState>((set, get) => ({
         (a, b) => (b.time?.created || 0) - (a.time?.created || 0)
       );
       set({ sessions, isLoadingSessions: false });
+      void get().runAutoCleanup(sessions);
     } catch (error) {
       console.error('Failed to load sessions:', error);
       set({ isLoadingSessions: false });
diff --git a/packages/web/server/index.js b/packages/web/server/index.js
index 866ec667..85c5dac8 100644
--- a/packages/web/server/index.js
+++ b/packages/web/server/index.js
@@ -281,6 +281,13 @@ const sanitizeSettingsUpdate = (payload) => {
   if (typeof candidate.showReasoningTraces === 'boolean') {
     result.showReasoningTraces = candidate.showReasoningTraces;
   }
+  if (typeof candidate.autoDeleteEnabled === 'boolean') {
+    result.autoDeleteEnabled = candidate.autoDeleteEnabled;
+  }
+  if (typeof candidate.autoDeleteAfterDays === 'number' && Number.isFinite(candidate.autoDeleteAfterDays)) {
+    const normalizedDays = Math.max(1, Math.min(365, Math.round(candidate.autoDeleteAfterDays)));
+    result.autoDeleteAfterDays = normalizedDays;
+  }
 
   const typography = sanitizeTypographySizesPartial(candidate.typographySizes);
   if (typography) {