From 27e16944808cf43210d4505993c9846fdd7309e4 Mon Sep 17 00:00:00 2001
From: "Kai (Tam Nhu) Tran" <61256810+kaitranntt@users.noreply.github.com>
Date: Sat, 30 May 2026 14:57:04 -0400
Subject: [PATCH] fix(cliproxy): prefer explicit Codex free fallbacks

---
 .../__tests__/codex-plan-compatibility.test.ts    | 15 +++++++++++++++
 .../ai-providers/codex-plan-compatibility.ts      |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/cliproxy/ai-providers/__tests__/codex-plan-compatibility.test.ts b/src/cliproxy/ai-providers/__tests__/codex-plan-compatibility.test.ts
index 28201039..45548c1d 100644
--- a/src/cliproxy/ai-providers/__tests__/codex-plan-compatibility.test.ts
+++ b/src/cliproxy/ai-providers/__tests__/codex-plan-compatibility.test.ts
@@ -78,6 +78,21 @@ describe('codex plan compatibility', () => {
     ).toBe('gpt-5.4-mini');
   });
 
+  it('prefers a rejected model explicit free-plan fallback over saved paid-only models', () => {
+    expect(
+      resolveRuntimeCodexFallbackModel({
+        requestedModel: 'gpt-5.3-codex-spark',
+        modelMap: {
+          defaultModel: 'gpt-5.3-codex',
+          opusModel: 'gpt-5.3-codex',
+          sonnetModel: 'gpt-5.3-codex',
+          haikuModel: 'gpt-5.3-codex-spark',
+        },
+        excludeModels: ['gpt-5.3-codex-spark'],
+      })
+    ).toBe('gpt-5.4-mini');
+  });
+
   it('tracks Codex thinking caps for current safe defaults, paid models, and legacy aliases', () => {
     expect(getModelMaxLevel('codex', 'gpt-5.5')).toBe('xhigh');
     expect(getModelMaxLevel('codex', 'gpt-5.4')).toBe('xhigh');
diff --git a/src/cliproxy/ai-providers/codex-plan-compatibility.ts b/src/cliproxy/ai-providers/codex-plan-compatibility.ts
index 291b396e..dad29a02 100644
--- a/src/cliproxy/ai-providers/codex-plan-compatibility.ts
+++ b/src/cliproxy/ai-providers/codex-plan-compatibility.ts
@@ -114,8 +114,8 @@ export function resolveRuntimeCodexFallbackModel(options: {
     (options.excludeModels ?? []).map((model) => normalizeCodexModelId(model)).filter(Boolean)
   );
   const candidates = [
-    options.modelMap.defaultModel,
     getFreePlanFallbackCodexModel(requestedModel),
+    options.modelMap.defaultModel,
     options.modelMap.opusModel,
     options.modelMap.sonnetModel,
     options.modelMap.haikuModel,