diff --git a/src/commands/setup-command.ts b/src/commands/setup-command.ts
index 5b7acf5a..bd17af07 100644
--- a/src/commands/setup-command.ts
+++ b/src/commands/setup-command.ts
@@ -113,12 +113,14 @@ async function selectOption(
 }
 
 /**
- * Check if this is a first-time install (config exists but is empty/unconfigured)
- * Returns true if user should be prompted to run setup wizard
+ * Check if this is a first-time install (config exists but is empty/unconfigured).
+ * Returns true if user should be prompted to run setup wizard.
  *
- * IMPORTANT: Also checks legacy config.json for existing profiles to avoid
- * treating users with existing GLM/Kimi setups as "first-time installs"
- * (Fix for issue #195 - GLM auth persistence regression)
+ * Detection priority:
+ * 1. setup_completed flag (explicit wizard completion)
+ * 2. Unified config content (profiles, accounts, variants, oauth_accounts, remote proxy)
+ * 3. Legacy config.json profiles (GLM, Kimi)
+ * 4. Legacy profiles.json accounts
  */
 export function isFirstTimeInstall(): boolean {
   // Check unified config first (config.yaml)
@@ -132,6 +134,11 @@ export function isFirstTimeInstall(): boolean {
       return false;
     }
 
+    // If setup wizard was completed, NOT first-time install
+    if (loaded.setup_completed) {
+      return false;
+    }
+
     // Check for any meaningful configuration in unified config
     const hasProfiles = Object.keys(loaded.profiles || {}).length > 0;
     const hasAccounts = Object.keys(loaded.accounts || {}).length > 0;
@@ -370,6 +377,7 @@ async function runSetupWizard(force: boolean = false): Promise<void> {
     }
 
     // Save config
+    config.setup_completed = true;
     saveUnifiedConfig(config);
 
     // Final summary
diff --git a/src/config/unified-config-loader.ts b/src/config/unified-config-loader.ts
index a495b7e3..4cf39d60 100644
--- a/src/config/unified-config-loader.ts
+++ b/src/config/unified-config-loader.ts
@@ -139,6 +139,7 @@ function mergeWithDefaults(partial: Partial<UnifiedConfig>): UnifiedConfig {
   const defaults = createEmptyUnifiedConfig();
   return {
     version: partial.version ?? defaults.version,
+    setup_completed: partial.setup_completed,
     default: partial.default ?? defaults.default,
     accounts: partial.accounts ?? defaults.accounts,
     profiles: partial.profiles ?? defaults.profiles,
@@ -326,6 +327,9 @@ function generateYamlWithComments(config: UnifiedConfig): string {
 
   // Version
   lines.push(`version: ${config.version}`);
+  if (config.setup_completed !== undefined) {
+    lines.push(`setup_completed: ${config.setup_completed}`);
+  }
   lines.push('');
 
   // Default
diff --git a/src/config/unified-config-types.ts b/src/config/unified-config-types.ts
index 2315f67d..f2d3618e 100644
--- a/src/config/unified-config-types.ts
+++ b/src/config/unified-config-types.ts
@@ -521,6 +521,8 @@ export const DEFAULT_DASHBOARD_AUTH_CONFIG: DashboardAuthConfig = {
 export interface UnifiedConfig {
   /** Config version (7 for quota management) */
   version: number;
+  /** Flag indicating setup wizard has been completed */
+  setup_completed?: boolean;
   /** Default profile name to use when none specified */
   default?: string;
   /** Account-based profiles (isolated Claude instances) */
diff --git a/tests/unit/commands/setup-command.test.ts b/tests/unit/commands/setup-command.test.ts
index e4bb37b4..8277aefb 100644
--- a/tests/unit/commands/setup-command.test.ts
+++ b/tests/unit/commands/setup-command.test.ts
@@ -115,6 +115,51 @@ cliproxy_server:
     });
   });
 
+  describe('setup_completed flag detection', () => {
+    it('should detect setup_completed flag in unified config', () => {
+      createConfigYaml(`
+version: 8
+setup_completed: true
+profiles: {}
+accounts: {}
+`);
+
+      const content = fs.readFileSync(path.join(testDir, 'config.yaml'), 'utf8');
+      const hasSetupCompleted = content.includes('setup_completed: true');
+
+      expect(hasSetupCompleted).toBe(true);
+    });
+
+    it('should treat missing setup_completed as first-time eligible', () => {
+      createConfigYaml(`
+version: 8
+profiles: {}
+accounts: {}
+`);
+
+      const content = fs.readFileSync(path.join(testDir, 'config.yaml'), 'utf8');
+      const hasSetupCompleted = content.includes('setup_completed: true');
+
+      expect(hasSetupCompleted).toBe(false);
+    });
+
+    it('should treat setup_completed: false as first-time eligible', () => {
+      createConfigYaml(`
+version: 8
+setup_completed: false
+profiles: {}
+accounts: {}
+`);
+
+      const content = fs.readFileSync(path.join(testDir, 'config.yaml'), 'utf8');
+      const hasSetupCompletedTrue = content.includes('setup_completed: true');
+      const hasSetupCompletedFalse = content.includes('setup_completed: false');
+
+      expect(hasSetupCompletedTrue).toBe(false);
+      expect(hasSetupCompletedFalse).toBe(true);
+    });
+  });
+
   describe('corrupted config handling', () => {
     it('should handle corrupted config.json gracefully', () => {
       fs.writeFileSync(path.join(testDir, 'config.json'), 'not valid json{{{', 'utf8');