fix(auth): order the ChatGPT model list as the Codex backend does

gpt-6.1-terra sat third, ahead of gpt-6-sol, gpt-6-luna and gpt-5.6-sol,
although the backend lists it after gpt-5.6-sol. Nothing pinned the
order, since the other tests read the constant, so a test now does.

The comment no longer says the retirement applies to ChatGPT sign-in
only. The retirement notice is OpenAI documentation, which does not say
whether API access is affected, so the comment states only that the
three models are left out because the documentation lists them as
retired for ChatGPT.

Author: bwachman

src/auth/codex/constants.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, test } from "bun:test";
+
+import { CODEX_DEFAULT_MODELS } from "./constants.js";
+
+describe("CODEX_DEFAULT_MODELS", () => {
+  // The order the Codex backend listed these models in; the first is the
+  // ChatGPT default. Nothing else pins it: the other tests read the constant.
+  test("follows the order the Codex backend lists the models in", () => {
+    expect([...CODEX_DEFAULT_MODELS]).toEqual([
+      "gpt-6.1-sol",
+      "gpt-6-astra",
+      "gpt-6-sol",
+      "gpt-6-luna",
+      "gpt-5.6-sol",
+      "gpt-6.1-terra",
+      "gpt-5.6-terra",
+      "gpt-5.6-luna",
+    ]);
+  });
+
+  test("leaves out the models OpenAI's documentation lists as retired for ChatGPT", () => {
+    for (const retired of ["gpt-5.4", "gpt-5.4-mini", "gpt-5.5"]) {
+      expect(CODEX_DEFAULT_MODELS as readonly string[]).not.toContain(retired);
+    }
+  });
+});

src/auth/codex/constants.ts

@@ -21,17 +21,19 @@ export const CODEX_CLIENT_VERSION = "0.50.0";
 // the public Codex CLI originator.
 export const CODEX_ORIGINATOR = "codex_cli_rs";
 
-// The models a ChatGPT sign-in can select, in the Codex backend's priority
-// order (GET /codex/models); the first entry is the ChatGPT default. OpenAI
-// retires models for ChatGPT sign-in on its own schedule, independently of the
-// OpenAI API, so this list and its default do not follow the API-key path.
+// The models a ChatGPT sign-in offers, in the order the Codex backend lists
+// them (GET /codex/models); the first entry is the ChatGPT default. gpt-5.4,
+// gpt-5.4-mini and gpt-5.5 are left out because OpenAI's documentation lists
+// them as retired for ChatGPT, whether or not the backend still returns them.
+// The OpenAI API-key path has its own list and default and does not follow
+// this one.
 export const CODEX_DEFAULT_MODELS = [
   "gpt-6.1-sol",
   "gpt-6-astra",
-  "gpt-6.1-terra",
   "gpt-6-sol",
   "gpt-6-luna",
   "gpt-5.6-sol",
+  "gpt-6.1-terra",
   "gpt-5.6-terra",
   "gpt-5.6-luna",
 ] as const;