diff --git a/src/ui/components/settings/sections/BudgetSection.tsx b/src/ui/components/settings/sections/BudgetSection.tsx
index 7b329f1..f645942 100644
--- a/src/ui/components/settings/sections/BudgetSection.tsx
+++ b/src/ui/components/settings/sections/BudgetSection.tsx
@@ -1,3 +1,4 @@
+import { useState, useEffect } from "react";
 import { Switch } from "@ui/components/ui/switch";
 import { Slider } from "@ui/components/ui/slider";
 import { SettingsRow } from "../SettingsRow";
@@ -5,14 +6,25 @@ import {
     useGlobalSettings,
     useUpdateGlobalSetting,
 } from "@core/api/useSettings";
+import { undoToast } from "@ui/lib/toast";
 
 export function BudgetSection() {
     const { data: settings } = useGlobalSettings();
     const { mutate: updateSetting } = useUpdateGlobalSetting();
 
-    if (!settings) return null;
+    // Local slider state — only persisted on mouse-up / touch-end
+    const [localCeiling, setLocalCeiling] = useState<number | undefined>(
+        undefined,
+    );
+
+    // Sync from server when settings load or change externally
+    useEffect(() => {
+        if (settings) setLocalCeiling(settings.budgetCeilingPercent);
+    }, [settings]);
+
+    if (!settings || localCeiling === undefined) return null;
 
-    const ceiling = settings.budgetCeilingPercent;
+    const ceiling = localCeiling;
     const reserved = 100 - ceiling;
 
     return (
@@ -44,11 +56,26 @@ export function BudgetSection() {
                             <Slider
                                 value={[ceiling]}
                                 onValueChange={([value]) =>
+                                    setLocalCeiling(value)
+                                }
+                                onValueCommit={([value]) => {
+                                    const prev = settings.budgetCeilingPercent;
+                                    if (prev === value) return;
                                     updateSetting({
                                         key: "budgetCeilingPercent",
                                         value,
-                                    })
-                                }
+                                    });
+                                    undoToast(
+                                        `Budget ceiling → ${value}%`,
+                                        () => {
+                                            setLocalCeiling(prev);
+                                            updateSetting({
+                                                key: "budgetCeilingPercent",
+                                                value: prev,
+                                            });
+                                        },
+                                    );
+                                }}
                                 min={10}
                                 max={100}
                                 step={5}
diff --git a/src/ui/components/settings/sections/ProjectSection.tsx b/src/ui/components/settings/sections/ProjectSection.tsx
index a68b194..ac95230 100644
--- a/src/ui/components/settings/sections/ProjectSection.tsx
+++ b/src/ui/components/settings/sections/ProjectSection.tsx
@@ -1,4 +1,4 @@
-import { useState, useEffect, useRef, useCallback } from "react";
+import { useState, useEffect, useRef, useCallback, useMemo } from "react";
 import { useRepositories, useGitBranches } from "@core/api/useRepositories";
 import {
     useGlobalSettings,
@@ -19,6 +19,7 @@ import { Slider } from "@ui/components/ui/slider";
 import type { BranchPrefixMode } from "@core/types/settings";
 import type { ScheduleMode } from "@core/types/agent";
 import { Trash2, Clock, Zap, Hand } from "lucide-react";
+import { undoToast } from "@ui/lib/toast";
 
 interface ProjectSectionProps {
     repositoryId: string;
@@ -53,6 +54,22 @@ export function ProjectSection({
     const agentPrefsDirty = useRef(false);
     const scanPrefsDirty = useRef(false);
 
+    // Local slider state for project budget — only persisted on mouse-up
+    const [localBudget, setLocalBudget] = useState<number | undefined>(
+        undefined,
+    );
+    const serverBudget = useMemo(
+        () =>
+            overrides && globalSettings
+                ? (overrides.overrideBudgetCeilingPercent ??
+                  globalSettings.budgetCeilingPercent)
+                : undefined,
+        [overrides, globalSettings],
+    );
+    useEffect(() => {
+        if (serverBudget !== undefined) setLocalBudget(serverBudget);
+    }, [serverBudget]);
+
     const repo = repositories?.find((r) => r.id === repositoryId);
     const { data: branches } = useGitBranches(repo?.path);
 
@@ -124,6 +141,7 @@ export function ProjectSection({
     const effectiveSchedule =
         agentConfig?.scheduleMode ?? (globalSettings.agentMode as ScheduleMode);
     const effectiveBudget =
+        localBudget ??
         overrides.overrideBudgetCeilingPercent ??
         globalSettings.budgetCeilingPercent;
 
@@ -421,13 +439,23 @@ export function ProjectSection({
                                 <button
                                     key={mode.value}
                                     type="button"
-                                    onClick={() =>
+                                    onClick={() => {
+                                        const prev = effectiveSchedule;
+                                        if (prev === mode.value) return;
                                         updateAgentConfig({
                                             repositoryId,
                                             scheduleMode:
                                                 mode.value as ScheduleMode,
-                                        })
-                                    }
+                                        });
+                                        undoToast(
+                                            `Schedule → ${mode.label}`,
+                                            () =>
+                                                updateAgentConfig({
+                                                    repositoryId,
+                                                    scheduleMode: prev,
+                                                }),
+                                        );
+                                    }}
                                     className={`group flex items-center gap-1.5 rounded-md px-2.5 py-1.5 text-xs transition-all duration-200 ${
                                         isSelected
                                             ? "bg-foreground text-background shadow-sm"
@@ -495,13 +523,35 @@ export function ProjectSection({
                     <div className="flex shrink-0 items-center gap-3">
                         <Slider
                             value={[effectiveBudget]}
-                            onValueChange={([value]) =>
+                            onValueChange={([value]) => setLocalBudget(value)}
+                            onValueCommit={([value]) => {
+                                const prev = serverBudget;
+                                if (prev === undefined || prev === value)
+                                    return;
+                                const hadOverride =
+                                    overrides.overrideBudgetCeilingPercent !==
+                                    undefined;
                                 updateOverride({
                                     repositoryId,
                                     field: "overrideBudgetCeilingPercent",
                                     value,
-                                })
-                            }
+                                });
+                                undoToast(`Project budget → ${value}%`, () => {
+                                    setLocalBudget(prev);
+                                    if (!hadOverride) {
+                                        clearOverride({
+                                            repositoryId,
+                                            field: "overrideBudgetCeilingPercent",
+                                        });
+                                    } else {
+                                        updateOverride({
+                                            repositoryId,
+                                            field: "overrideBudgetCeilingPercent",
+                                            value: prev,
+                                        });
+                                    }
+                                });
+                            }}
                             min={10}
                             max={100}
                             step={5}
diff --git a/src/ui/components/settings/sections/SchedulingSection.tsx b/src/ui/components/settings/sections/SchedulingSection.tsx
index ea3f12a..16e3208 100644
--- a/src/ui/components/settings/sections/SchedulingSection.tsx
+++ b/src/ui/components/settings/sections/SchedulingSection.tsx
@@ -16,6 +16,7 @@ import type {
     ScanFrequency,
 } from "@core/types/settings";
 import { Clock, Zap, Hand } from "lucide-react";
+import { undoToast } from "@ui/lib/toast";
 
 const AGENT_MODES: {
     value: AgentMode;
@@ -112,12 +113,22 @@ export function SchedulingSection() {
                                     <button
                                         key={mode.value}
                                         type="button"
-                                        onClick={() =>
+                                        onClick={() => {
+                                            const prev = settings.agentMode;
+                                            if (prev === mode.value) return;
                                             updateSetting({
                                                 key: "agentMode",
                                                 value: mode.value,
-                                            })
-                                        }
+                                            });
+                                            undoToast(
+                                                `Agent mode → ${mode.label}`,
+                                                () =>
+                                                    updateSetting({
+                                                        key: "agentMode",
+                                                        value: prev,
+                                                    }),
+                                            );
+                                        }}
                                         className={`group flex flex-1 flex-col items-start gap-1.5 rounded-md px-3 py-2.5 text-left transition-all duration-200 ${
                                             isSelected
                                                 ? "bg-foreground text-background shadow-sm"
diff --git a/src/ui/lib/toast.tsx b/src/ui/lib/toast.tsx
index cfb9a5c..3bd6054 100644
--- a/src/ui/lib/toast.tsx
+++ b/src/ui/lib/toast.tsx
@@ -1,7 +1,64 @@
 import { toast } from "sonner";
-import { Check, Clock } from "lucide-react";
+import { Check, Clock, Undo2 } from "lucide-react";
+
+/**
+ * When an undo toast is visible we suppress the normal "Saved" toast so the
+ * two don't fight for the user's attention. The flag is set when `undoToast`
+ * fires and cleared after the undo window expires or the user clicks Undo.
+ */
+let undoActive = false;
+let undoTimer: ReturnType<typeof setTimeout> | undefined;
+
+const UNDO_DURATION = 5000;
+
+function markUndoActive() {
+    undoActive = true;
+    clearTimeout(undoTimer);
+    undoTimer = setTimeout(() => {
+        undoActive = false;
+    }, UNDO_DURATION + 500); // small buffer past toast duration
+}
+
+/**
+ * Shows a toast with an "Undo" button. If the user clicks Undo within the
+ * duration window, `onUndo` fires and the toast is dismissed. Otherwise the
+ * toast disappears and the change sticks.
+ *
+ * While the undo toast is visible, `savedToast()` calls are suppressed so the
+ * two toasts don't overlap or replace each other.
+ */
+export function undoToast(message: string, onUndo: () => void) {
+    const id = "settings-undo";
+    markUndoActive();
+    toast.custom(
+        () => (
+            <div className="flex items-center gap-2 rounded-full bg-foreground pl-2.5 pr-1 py-1 shadow-md animate-fade-in-up">
+                <span className="text-[12px] font-medium text-background">
+                    {message}
+                </span>
+                <button
+                    type="button"
+                    onClick={() => {
+                        markUndoActive(); // suppress savedToast from the undo mutation too
+                        onUndo();
+                        toast.dismiss(id);
+                    }}
+                    className="flex items-center gap-1 rounded-full bg-background/15 px-2 py-0.5 text-[11px] font-medium text-background hover:bg-background/25 transition-colors"
+                >
+                    <Undo2 className="h-2.5 w-2.5" />
+                    Undo
+                </button>
+            </div>
+        ),
+        { id, duration: UNDO_DURATION },
+    );
+}
 
 export function savedToast() {
+    // Don't show "Saved" while an undo toast is active — the undo toast
+    // already communicates that the change was applied.
+    if (undoActive) return;
+
     toast.custom(
         () => (
             <div className="flex items-center gap-1.5 rounded-full bg-foreground pl-2 pr-2.5 py-1 shadow-md animate-fade-in-up">