Using Codex to Fix a LiteLLM Pricing-Markup Bug in Docker

Melvin Vivas · X post · 2026-07-29 · Open on X

Topics: AI Dev Tools & Productivity, LLMOps, Deployment & Monitoring · Level: intermediate

Summary

The creator used the Codex coding agent to fix a pricing-markup bug in LiteLLM by editing the code inside the Docker container where LiteLLM was running. It's a real example of a coding agent patching a third-party LLM gateway in place.

Key points

• LiteLLM's pricing-markup feature had a bug that the creator needed fixed.
• Codex first found the bug, then patched the code inside the running Docker container.
• Coding agents can debug and patch open-source infrastructure you depend on, not just your own code.
• Patching code inside a container is a quick fix; you would still need to rebuild the image or send the fix upstream so it isn't lost.

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
• LiteLLM · tool · github.com · free · recommended by both Bashiri Smith & Melvin Vivas
  An open-source LLM gateway/proxy that gives one API for many model providers, with cost tracking and pricing features.
  Also in: 7 Habits to Become an AI Engineer: Books, Tooling, Research & Shipping (Bashiri Smith on Facebook · notes), Codex Finds a Bug in a LiteLLM Feature (Melvin Vivas on X · notes)