GPT-6 Astra Medium in Codex as a Low-Cost Fine-Tuning Assistant

Melvin Vivas · X post · 2026-09-14 · Open on X

Topics: Fine-tuning & Model Customization, AI Dev Tools & Productivity · Level: intermediate

Summary

The creator recommends GPT-6 Astra on the medium setting in Codex as an assistant for fine-tuning and training small models, because it doesn't use much of your usage allowance.

Key points

• GPT-6 Astra medium in Codex uses little of your allowance when assisting with fine-tuning or training.
• He recommends making it your default for small-model training work.

Resources mentioned

• OpenAI Codex · tool · openai.com · paid
  OpenAI's coding agent. In the diagram it writes code, fixes review findings and drives the build loop. The creator also used it to make this video.
  Also in: An agent bot that installs and drives Codex on its own (Melvin Vivas on X · notes), Asking a Coder bot to install Codex (Melvin Vivas on X · notes), Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Codex Cloud Environments Must Be Saved & Published Before Use (Melvin Vivas on X · notes) and 240 more
• GPT-6 Astra · tool · openai.com · paid
  The model announced in the quoted launch post, pitched as the developer's most capable model for work, coding, science and cybersecurity, and able to operate a computer.
  Also in: Customizing Your Coding Setup with Pi Coding Agent Extensions (Melvin Vivas on X · notes), Pi Agent Council: Ask Multiple LLMs in Parallel and Compare Their Advice (Melvin Vivas on X · notes), Use GPT-6.1 Sol by Default, Save Astra for Emergencies (Melvin Vivas on X · notes), Dots in ChatGPT: always-on AI agents that you hand responsibilities to (Melvin Vivas on X · notes) and 49 more

Try this

• Use GPT-6 Astra medium in Codex as your assistant when fine-tuning or training small models.