Codex Multi-Agent Setup: Astra as Orchestrator, Luna for Subagents

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

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

Summary

The creator shares his current Codex setup: a project-level config.toml that uses GPT-6 Astra on medium reasoning as the orchestrator and GPT-5.6 Luna on max for the subagents. He suggests Terra might also work for subagents, says to tweak it as needed, and links his open-source config repo.

Key points

• Put the configuration in a project-level config.toml in Codex.
• Orchestrator: GPT-6 Astra at medium reasoning effort.
• Subagents: GPT-5.6 Luna at max reasoning effort.
• GPT-5.6 Terra could also work for subagents (he hasn't tried it).
• The repo also supports Sol instead of Astra as the orchestrator.
• Adjust the model choices to fit your needs.

Resources mentioned

• donvito/codex-astra-luna-orchestrator · repo · github.com · free
  The creator's Codex skill for an orchestrator-plus-subagents setup (Astra orchestrator, Luna subagents), configured through config.toml.
  Also in: Codex Orchestrator Pattern: Astra/Sol Orchestrator with Luna Subagents (Melvin Vivas on X · notes), Open-source Codex skill: Astra/Sol orchestrator with Luna subagents (Melvin Vivas on X · notes), Cost-Efficient Codex Subagents: Astra/Sol Orchestrator + Luna Workers (Melvin Vivas on X · notes), Codex Orchestrator v0.2.1: GPT-6 Sol orchestrator with Luna subagents (Melvin Vivas on X · notes) and 27 more
• 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

• Clone the repo and add a project-level config.toml to your Codex project.
• Try Terra instead of Luna for subagents and compare the results.