diff --git a/src/auth/profile-detector.ts b/src/auth/profile-detector.ts
index 16accd5f..a3fad69b 100644
--- a/src/auth/profile-detector.ts
+++ b/src/auth/profile-detector.ts
@@ -39,6 +39,8 @@ export interface ProfileDetectionResult {
   message?: string;
   /** For cliproxy variants: the underlying provider (gemini, codex, agy, qwen) */
   provider?: CLIProxyProfileName;
+  /** For cliproxy variants: dedicated port for isolation (8318-8417) */
+  port?: number;
   /** For unified config profiles: merged env vars (config + secrets) */
   env?: Record<string, string>;
   /** For copilot profile: the copilot config */
@@ -110,6 +112,8 @@ class ProfileDetector {
         type: 'cliproxy',
         name: profileName,
         provider: variant.provider as CLIProxyProfileName,
+        settingsPath: variant.settings,
+        port: variant.port,
       };
     }
 
@@ -250,6 +254,7 @@ class ProfileDetector {
         name: profileName,
         provider: variant.provider as CLIProxyProfileName,
         settingsPath: variant.settings,
+        port: variant.port,
       };
     }
 
diff --git a/src/ccs.ts b/src/ccs.ts
index dc2df697..fc1d1d83 100644
--- a/src/ccs.ts
+++ b/src/ccs.ts
@@ -511,7 +511,11 @@ async function main(): Promise<void> {
       // CLIPROXY FLOW: OAuth-based profiles (gemini, codex, agy, qwen) or user-defined variants
       const provider = profileInfo.provider || (profileInfo.name as CLIProxyProvider);
       const customSettingsPath = profileInfo.settingsPath; // undefined for hardcoded profiles
-      await execClaudeWithCLIProxy(claudeCli, provider, remainingArgs, { customSettingsPath });
+      const variantPort = profileInfo.port; // variant-specific port for isolation
+      await execClaudeWithCLIProxy(claudeCli, provider, remainingArgs, {
+        customSettingsPath,
+        port: variantPort,
+      });
     } else if (profileInfo.type === 'copilot') {
       // COPILOT FLOW: GitHub Copilot subscription via copilot-api proxy
       const { executeCopilotProfile } = await import('./copilot');
diff --git a/src/cliproxy/cliproxy-executor.ts b/src/cliproxy/cliproxy-executor.ts
index f8ebbf20..d23e3506 100644
--- a/src/cliproxy/cliproxy-executor.ts
+++ b/src/cliproxy/cliproxy-executor.ts
@@ -154,7 +154,17 @@ export async function execClaudeWithCLIProxy(
   });
 
   // Use resolved port from proxy config (overrides ExecutorConfig)
-  if (proxyConfig.port !== CLIPROXY_DEFAULT_PORT) {
+  // Priority: CLI flags > Variant port (cfg.port) > config.yaml > default
+  // cfg.port is set if variant has dedicated port; proxyConfig.port comes from CLI/ENV/config.yaml
+  if (cfg.port && cfg.port !== CLIPROXY_DEFAULT_PORT) {
+    // Variant port already set via config param - keep it (highest priority after CLI flags)
+    // CLI flags would have been parsed in resolveProxyConfig and set proxyConfig.port
+    // So if proxyConfig.port differs from default AND cfg.port differs, CLI wins
+    if (proxyConfig.port !== CLIPROXY_DEFAULT_PORT) {
+      cfg.port = proxyConfig.port; // CLI/ENV override variant port
+    }
+    // else: keep cfg.port (variant port)
+  } else if (proxyConfig.port !== CLIPROXY_DEFAULT_PORT) {
     cfg.port = proxyConfig.port;
   }
 
diff --git a/ui/src/components/cliproxy/provider-editor/index.tsx b/ui/src/components/cliproxy/provider-editor/index.tsx
index 17aa3e7d..7e79ffaf 100644
--- a/ui/src/components/cliproxy/provider-editor/index.tsx
+++ b/ui/src/components/cliproxy/provider-editor/index.tsx
@@ -94,8 +94,9 @@ export function ProviderEditor({
   const accounts = authStatus.accounts || [];
 
   const handleApplyPreset = (updates: Record<string, string>) => {
+    const effectivePort = port ?? CLIPROXY_PORT;
     updateEnvValues({
-      ANTHROPIC_BASE_URL: `http://127.0.0.1:${CLIPROXY_PORT}/api/provider/${provider}`,
+      ANTHROPIC_BASE_URL: `http://127.0.0.1:${effectivePort}/api/provider/${provider}`,
       ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
       ...updates,
     });
@@ -103,8 +104,9 @@ export function ProviderEditor({
   };
 
   const handleCustomPresetApply = (values: ModelMappingValues, presetName?: string) => {
+    const effectivePort = port ?? CLIPROXY_PORT;
     updateEnvValues({
-      ANTHROPIC_BASE_URL: `http://127.0.0.1:${CLIPROXY_PORT}/api/provider/${provider}`,
+      ANTHROPIC_BASE_URL: `http://127.0.0.1:${effectivePort}/api/provider/${provider}`,
       ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
       ANTHROPIC_MODEL: values.default,
       ANTHROPIC_DEFAULT_OPUS_MODEL: values.opus,
diff --git a/ui/src/lib/preset-utils.ts b/ui/src/lib/preset-utils.ts
index 7b74ed6b..80ce9673 100644
--- a/ui/src/lib/preset-utils.ts
+++ b/ui/src/lib/preset-utils.ts
@@ -13,10 +13,12 @@ export const CLIPROXY_PORT = 8317;
  * Uses the first model's presetMapping or falls back to using defaultModel for all tiers
  *
  * @param provider - The provider ID (e.g., 'gemini', 'codex', 'agy')
+ * @param port - Optional custom port (defaults to CLIPROXY_PORT)
  * @returns Object with success status and applied preset name
  */
 export async function applyDefaultPreset(
-  provider: string
+  provider: string,
+  port?: number
 ): Promise<{ success: boolean; presetName?: string }> {
   const catalog = MODEL_CATALOGS[provider];
   if (!catalog) return { success: false };
@@ -30,9 +32,10 @@ export async function applyDefaultPreset(
     haiku: catalog.defaultModel,
   };
 
+  const effectivePort = port ?? CLIPROXY_PORT;
   const settings = {
     env: {
-      ANTHROPIC_BASE_URL: `http://127.0.0.1:${CLIPROXY_PORT}/api/provider/${provider}`,
+      ANTHROPIC_BASE_URL: `http://127.0.0.1:${effectivePort}/api/provider/${provider}`,
       ANTHROPIC_AUTH_TOKEN: 'ccs-internal-managed',
       ANTHROPIC_MODEL: mapping.default,
       ANTHROPIC_DEFAULT_OPUS_MODEL: mapping.opus,