What Does “Recommended Set of Models” Mean in Codex?

What Does “Recommended Set of Models” Mean?

The “Default: Recommended set of models” selector in Codex interfaces represents operating under OpenAI's recommended configurations rather than manually pinning a specific model. OpenAI does not document this label as an autonomous task-routing system or a single unified mechanism; rather, OpenAI documents several related default behaviors across different surfaces:

• Desktop and Web Controls: In the ChatGPT desktop app and ChatGPT Work on the web, users start with the default Power setting available to their account, with controls to move toward Faster or Smarter, or open Advanced to choose a specific model, reasoning effort, or speed.
• Local Configuration Files: The ChatGPT desktop app, Codex CLI, and IDE extension share the same config.toml configuration file. If you do not specify a model there, clients automatically use a recommended model.
• CLI Session Controls: In the Codex CLI, users can run the /model command to interactively pick an available model and reasoning level, or pass model flags directly.
• Cloud Chat Behavior: For Codex cloud chats, OpenAI currently documents that you cannot change the default model.

What Model Does Codex Recommend by Default?

When a model is not explicitly configured, Codex clients default to OpenAI's recommended primary coding model and default Power setting available to your plan tier. In OpenAI's documentation, gpt-5.6 (aliasing gpt-5.6-sol with medium reasoning effort) serves as the primary recommended flagship model for complex coding, computer use, and research tasks.

OpenAI provides explicit guidance on where each model family shines:

• Astra (gpt-6-astra): For the hardest end-to-end work. Choose Astra for complete workflows across code, apps, and research that need sustained reasoning and judgment.
• Sol (gpt-5.6-sol): For complex, open-ended work. Choose Sol for ambiguous, difficult, or high-value tasks that need extra analysis, judgment, or polish, such as complex code changes, deep research, or polished documents.
• Terra (gpt-5.6-terra): The pragmatic all-rounder. Choose Terra for everyday work that needs strong reasoning and tool use when you do not need Sol's full depth.
• Luna (gpt-5.6-luna): For clear, repeatable tasks. Choose Luna for specific, high-volume tasks when you know what a good result looks like, such as extraction, classification, transformation, and structured summaries.

Note on deprecations: The gpt-5.4 and gpt-5.4-mini models retired from Codex with ChatGPT sign-in on August 31, 2026. OpenAI officially instructs developers to replace gpt-5.4 with gpt-5.6-terra and gpt-5.4-mini with gpt-5.6-luna in saved configurations, custom agents, and scheduled tasks.

Does Default Automatically Choose Between Astra, Sol, Terra, and Luna?

No, OpenAI does not currently document Default as dynamically choosing a different model for each task. While community discussions often speculate that “Default: Recommended set of models” acts as an autonomous classifier that inspects prompt complexity and routes tasks among models, OpenAI’s official documentation does not describe that behavior.

OpenAI documents starting with the default Power setting available to your account and adjusting the slider toward Faster or Smarter, while Advanced allows selecting a specific model, reasoning effort, or speed. Developers who want a specific model for a task should adjust the Power slider, open Advanced, or declare a model explicitly in configuration.

What Does the Power Slider Change?

The Power control adjusts the balance between reasoning depth and execution speed by moving between predefined model and reasoning-effort presets. OpenAI advises users to start with the default Power setting available to their account, then move toward Smarter for deeper reasoning or toward Faster for faster, lower-cost work.

OpenAI notes that the picker illustrations show GPT-5.6 controls. For eligible Pro, Business ($100), and Enterprise accounts, the Astra rollout updates the Power options to predefined positions pairing model variants with specific reasoning efforts. When you want gpt-5.6-luna or a specific model, reasoning effort, or speed, OpenAI instructs users to open Advanced.

Does the Recommended Model Affect Codex Usage Limits?

Yes, the model and reasoning effort selected directly impact how quickly you consume your 5-hour rolling and weekly Codex allowances. While OpenAI does not publish fixed consumption multipliers or token multipliers per preset, higher-tier models and deeper reasoning configurations burn through available allowance substantially faster.

For example, OpenAI documents distinct estimated 5-hour local-message ranges depending on the model: on ChatGPT Plus, running GPT-6 Astra yields an official estimate of 5 to 45 local messages per 5 hours, whereas running lighter models allows for significantly higher message throughput under the overall published 5 to 2,000 local message range. On Pro $100 and Pro $200, allowances scale proportionally to 5× and 20× Plus levels.

How Do I Force Codex to Use a Specific Model?

You can force Codex to use a specific model through the Advanced menu, interactive CLI commands, command-line flags, or your persistent config.toml file. Four supported methods allow you to bypass default recommendations:

Frequently Asked Questions