Use Codex to Prepare Fine-Tuning Datasets

Melvin Vivas · X post · 2026-09-15 · Open on X

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

Summary

Tip: when you train a model, ask Codex to help prepare the dataset. It can research the data format your base model needs.

Key points

• Ask a coding agent to prepare your training dataset.
• Codex can look up the chat or template format that your chosen base model requires.
• This saves you from checking format details by hand before fine-tuning.

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

Try this

• When fine-tuning, ask Codex to prepare your dataset in the format your base model requires.