diff --git a/packages/cli/src/config/settings.test.ts b/packages/cli/src/config/settings.test.ts
index 9db17b7d3..a8ebcffe5 100644
--- a/packages/cli/src/config/settings.test.ts
+++ b/packages/cli/src/config/settings.test.ts
@@ -55,6 +55,7 @@ import { disableExtension } from './extension.js';
 
 // These imports will get the versions from the vi.mock('./settings.js', ...) factory.
 import {
+  getSettingsWarnings,
   loadSettings,
   USER_SETTINGS_PATH, // This IS the mocked path.
   getSystemSettingsPath,
@@ -418,6 +419,84 @@ describe('Settings Loading and Merging', () => {
       });
     });
 
+    it('should warn about deprecated legacy keys in a v2 settings file', () => {
+      (mockFsExistsSync as Mock).mockImplementation(
+        (p: fs.PathLike) => p === USER_SETTINGS_PATH,
+      );
+      const userSettingsContent = {
+        [SETTINGS_VERSION_KEY]: SETTINGS_VERSION,
+        usageStatisticsEnabled: false,
+      };
+      (fs.readFileSync as Mock).mockImplementation(
+        (p: fs.PathOrFileDescriptor) => {
+          if (p === USER_SETTINGS_PATH)
+            return JSON.stringify(userSettingsContent);
+          return '{}';
+        },
+      );
+
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+
+      expect(getSettingsWarnings(settings)).toEqual(
+        expect.arrayContaining([
+          expect.stringContaining(
+            "Deprecated setting 'usageStatisticsEnabled'",
+          ),
+        ]),
+      );
+      expect(getSettingsWarnings(settings)).toEqual(
+        expect.arrayContaining([
+          expect.stringContaining("'privacy.usageStatisticsEnabled'"),
+        ]),
+      );
+    });
+
+    it('should warn about unknown top-level keys in a v2 settings file', () => {
+      (mockFsExistsSync as Mock).mockImplementation(
+        (p: fs.PathLike) => p === USER_SETTINGS_PATH,
+      );
+      const userSettingsContent = {
+        [SETTINGS_VERSION_KEY]: SETTINGS_VERSION,
+        someUnknownKey: 'value',
+      };
+      (fs.readFileSync as Mock).mockImplementation(
+        (p: fs.PathOrFileDescriptor) => {
+          if (p === USER_SETTINGS_PATH)
+            return JSON.stringify(userSettingsContent);
+          return '{}';
+        },
+      );
+
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+
+      expect(getSettingsWarnings(settings)).toEqual(
+        expect.arrayContaining([
+          expect.stringContaining("Unknown setting 'someUnknownKey'"),
+        ]),
+      );
+    });
+
+    it('should not warn for valid v2 container keys', () => {
+      (mockFsExistsSync as Mock).mockImplementation(
+        (p: fs.PathLike) => p === USER_SETTINGS_PATH,
+      );
+      const userSettingsContent = {
+        [SETTINGS_VERSION_KEY]: SETTINGS_VERSION,
+        model: { name: 'qwen-coder' },
+      };
+      (fs.readFileSync as Mock).mockImplementation(
+        (p: fs.PathOrFileDescriptor) => {
+          if (p === USER_SETTINGS_PATH)
+            return JSON.stringify(userSettingsContent);
+          return '{}';
+        },
+      );
+
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+
+      expect(getSettingsWarnings(settings)).toEqual([]);
+    });
+
     it('should rewrite allowedTools to tools.allowed during migration', () => {
       (mockFsExistsSync as Mock).mockImplementation(
         (p: fs.PathLike) => p === USER_SETTINGS_PATH,
diff --git a/packages/cli/src/config/settings.ts b/packages/cli/src/config/settings.ts
index ae29074b2..5c8fec3cb 100644
--- a/packages/cli/src/config/settings.ts
+++ b/packages/cli/src/config/settings.ts
@@ -344,6 +344,97 @@ const KNOWN_V2_CONTAINERS = new Set(
   Object.values(MIGRATION_MAP).map((path) => path.split('.')[0]),
 );
 
+function getSettingsFileKeyWarnings(
+  settings: Record<string, unknown>,
+  settingsFilePath: string,
+): string[] {
+  const version = settings[SETTINGS_VERSION_KEY];
+  if (typeof version !== 'number' || version < SETTINGS_VERSION) {
+    return [];
+  }
+
+  const warnings: string[] = [];
+  const deprecatedKeys = new Set<string>();
+
+  // Deprecated keys (V1 top-level keys that moved to a nested V2 path).
+  for (const [oldKey, newPath] of Object.entries(MIGRATION_MAP)) {
+    if (oldKey === newPath) {
+      continue;
+    }
+    if (!(oldKey in settings)) {
+      continue;
+    }
+
+    const oldValue = settings[oldKey];
+
+    // If this key is a V2 container (like 'model') and it's already an object,
+    // it's likely already in V2 format. Don't warn.
+    if (
+      KNOWN_V2_CONTAINERS.has(oldKey) &&
+      typeof oldValue === 'object' &&
+      oldValue !== null &&
+      !Array.isArray(oldValue)
+    ) {
+      continue;
+    }
+
+    deprecatedKeys.add(oldKey);
+    warnings.push(
+      `⚠️  Warning: Deprecated setting '${oldKey}' in ${settingsFilePath}. Please use '${newPath}' instead.`,
+    );
+  }
+
+  // Unknown top-level keys.
+  const schemaKeys = new Set(Object.keys(getSettingsSchema()));
+  for (const key of Object.keys(settings)) {
+    if (key === SETTINGS_VERSION_KEY) {
+      continue;
+    }
+    if (deprecatedKeys.has(key)) {
+      continue;
+    }
+    if (schemaKeys.has(key)) {
+      continue;
+    }
+
+    warnings.push(
+      `⚠️  Warning: Unknown setting '${key}' in ${settingsFilePath}. This setting will be ignored.`,
+    );
+  }
+
+  return warnings;
+}
+
+/**
+ * Collects warnings for deprecated and unknown settings keys.
+ *
+ * For `$version: 2` settings files, we do not apply implicit migrations.
+ * Instead, we surface actionable, de-duplicated warnings in the terminal UI.
+ */
+export function getSettingsWarnings(loadedSettings: LoadedSettings): string[] {
+  const warningSet = new Set<string>();
+
+  for (const scope of [SettingScope.User, SettingScope.Workspace]) {
+    const settingsFile = loadedSettings.forScope(scope);
+    if (settingsFile.rawJson === undefined) {
+      continue; // File not present / not loaded.
+    }
+    const settingsObject = settingsFile.originalSettings as unknown as Record<
+      string,
+      unknown
+    >;
+
+    for (const warning of getSettingsFileKeyWarnings(
+      settingsObject,
+      settingsFile.path,
+    )) {
+      warningSet.add(warning);
+    }
+  }
+
+  return [...warningSet];
+}
+
 export function migrateSettingsToV1(
   v2Settings: Record<string, unknown>,
 ): Record<string, unknown> {
diff --git a/packages/cli/src/gemini.tsx b/packages/cli/src/gemini.tsx
index b05f12453..4591cf1d1 100644
--- a/packages/cli/src/gemini.tsx
+++ b/packages/cli/src/gemini.tsx
@@ -17,7 +17,11 @@ import * as cliConfig from './config/config.js';
 import { loadCliConfig, parseArguments } from './config/config.js';
 import { ExtensionStorage, loadExtensions } from './config/extension.js';
 import type { DnsResolutionOrder, LoadedSettings } from './config/settings.js';
-import { loadSettings, migrateDeprecatedSettings } from './config/settings.js';
+import {
+  getSettingsWarnings,
+  loadSettings,
+  migrateDeprecatedSettings,
+} from './config/settings.js';
 import {
   initializeApp,
   type InitializationResult,
@@ -400,12 +404,15 @@ export async function main() {
 
     let input = config.getQuestion();
     const startupWarnings = [
-      ...(await getStartupWarnings()),
-      ...(await getUserStartupWarnings({
-        workspaceRoot: process.cwd(),
-        useRipgrep: settings.merged.tools?.useRipgrep ?? true,
-        useBuiltinRipgrep: settings.merged.tools?.useBuiltinRipgrep ?? true,
-      })),
+      ...new Set([
+        ...(await getStartupWarnings()),
+        ...(await getUserStartupWarnings({
+          workspaceRoot: process.cwd(),
+          useRipgrep: settings.merged.tools?.useRipgrep ?? true,
+          useBuiltinRipgrep: settings.merged.tools?.useBuiltinRipgrep ?? true,
+        })),
+        ...getSettingsWarnings(settings),
+      ]),
     ];
 
     // Render UI, passing necessary config values. Check that there is no command line question.