Save Codex limits: plan in ChatGPT with the GitHub plugin

Melvin Vivas · X post · 2026-09-16 · Open on X

Topics: AI Dev Tools & Productivity, AI Agents, Tool Use & MCP · Level: intermediate

Summary

A workflow tip for saving Codex usage limits. Instead of using Codex's plan mode, plan the feature in a ChatGPT chat using the GitHub plugin by pasting your repo URL. Then switch to Codex only to implement the plan.

Key points

• Don't use plan mode in Codex, because it uses up your Codex limits
• Plan in a ChatGPT chat with the GitHub plugin/connector instead
• Paste your GitHub repo URL and ask ChatGPT to plan the new feature
• Planning in ChatGPT doesn't count against Codex limits
• Once you have the plan, switch to Codex for implementation

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
• ChatGPT · tool · chatgpt.com · free · recommended by both Bashiri Smith & Melvin Vivas
  OpenAI's AI assistant (web, desktop and mobile apps), used for chat, coding, writing and image generation.
  Also in: Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Dots Demo: A Voice AI Agent Handling Travel Booking and Feedback Triage (Melvin Vivas on X · notes), ChatGPT Can Commit Code Directly to Your GitHub Repo (Melvin Vivas on X · notes), OpenAI Dots: Agents Inside ChatGPT That Debug, Fix, and Open PRs (Melvin Vivas on X · notes) and 23 more
• ChatGPT GitHub plugin (connector) · tool · paid
  ChatGPT integration that lets the chat read a GitHub repository.

Try this

• Plan new features in ChatGPT with the GitHub plugin instead of Codex's plan mode
• Paste your repo URL into ChatGPT and ask for a feature plan
• Implement the finished plan in Codex