fix(codex): skip model fallback when user has ChatGPT subscription

Check `codex login status` before the model availability check.
If the user is logged in via ChatGPT subscription, gpt-5.3-codex
is accessible natively and no fallback is needed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Connoropolous

packages/codex-runner/src/CodexRunner.ts

@@ -486,6 +486,10 @@ export class CodexRunner extends EventEmitter implements IAgentRunner {
 	/**
 	 * Check if the configured model is accessible via the OpenAI API.
 	 * If not, swap to the fallback model before starting the session.
+	 *
+	 * Skipped when:
+	 * - No OPENAI_API_KEY is set (Codex-native auth handles model access)
+	 * - The user has a ChatGPT subscription (`codex login status` reports "Logged in using ChatGPT")
 	 */
 	private async resolveModelWithFallback(): Promise<void> {
 		const model = this.config.model;
@@ -495,6 +499,8 @@ export class CodexRunner extends EventEmitter implements IAgentRunner {
 		const apiKey = process.env.OPENAI_API_KEY;
 		if (!apiKey) return;
 
+		if (await this.hasCodexSubscription()) return;
+
 		const baseUrl = (
 			process.env.OPENAI_BASE_URL ||
 			process.env.OPENAI_API_BASE ||
@@ -522,6 +528,26 @@ export class CodexRunner extends EventEmitter implements IAgentRunner {
 		}
 	}
 
+	/**
+	 * Check if the user has a ChatGPT/Codex subscription by running `codex login status`.
+	 * Returns true when the output contains "Logged in using ChatGPT",
+	 * meaning the user has native Codex auth and can access gpt-5.3-codex.
+	 */
+	private async hasCodexSubscription(): Promise<boolean> {
+		const codexBin = this.config.codexPath || "codex";
+		try {
+			const { execFile } = await import("node:child_process");
+			const { promisify } = await import("node:util");
+			const execFileAsync = promisify(execFile);
+			const { stdout } = await execFileAsync(codexBin, ["login", "status"], {
+				timeout: 5_000,
+			});
+			return /logged in using chatgpt/i.test(stdout);
+		} catch {
+			return false;
+		}
+	}
+
 	private createCodexClient(): Codex {
 		const codexHome = this.resolveCodexHome();
 		const envOverride = this.buildEnvOverride(codexHome);