Match Model and Reasoning Level to Task Complexity in Coworker

Melvin Vivas · X post · 2026-09-05 · Open on X

Topics: AI Dev Tools & Productivity, LLM Fundamentals · Level: intermediate

Summary

While building a headless mode for Coworker, the creator runs GPT-6 Astra on its low reasoning setting so his usage limits last longer. He switches to the cheaper Luna model when a task is simpler. The takeaway is to route each task to a model tier based on how hard it is.

Key points

• The creator is building a headless (non-interactive) mode for Coworker.
• He uses GPT-6 Astra on the 'low' reasoning setting to make usage last longer.
• He deliberately switches to Luna for simpler tasks.
• Matching the model and reasoning effort to the task saves cost and quota.

Resources mentioned

• Coworker (donvito/coworker) · repo · github.com · free
  The creator's local-first desktop app where you pick an AI coworker and have it produce work such as invoices as finished PDFs.
  Also in: Claude Opus 5.5 for Video Making: Creator's Showcase Thread (Coworker) (Melvin Vivas on X · notes), Coworker: free open-source desktop AI coworker app (Melvin Vivas on X · notes), Coworker: Open-Source Desktop App for AI Agents (Melvin Vivas on X · notes), Using Devin AI to Test the Coworker Desktop App on Windows (Melvin Vivas on X · notes) and 38 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
• Luna · tool · openai.com · paid
  The other model/agent the classifier routes tasks to; the post doesn't describe it further.
  Also in: GPT-6.1 Sol May Beat Luna for Subagents (Melvin Vivas on X · notes), Picking models for orchestrator and subagent roles in Codex (Melvin Vivas on X · notes), GPT-6 Sol Ultra Subagents Use Up Limits Fast (Melvin Vivas on X · notes), GPT-6 Sol vs Opus 5.5 in a Livestream Comparison (Melvin Vivas on X · notes) and 14 more

Try this

• Use a low reasoning setting on expensive models to make usage last longer.
• Switch to a cheaper model like Luna for simple tasks.