Jevons Paradox: Discounted GPT 5.6 Terra/Luna Raised Token Use 13.8x

Melvin Vivas · X post · 2026-08-28 · Open on X

Topics: Industry Trends & Job Market, LLM Fundamentals, LLMOps, Deployment & Monitoring · Level: beginner

Summary

When OpenRouter heavily discounted GPT 5.6 Terra and Luna, token usage went up 13.8x. The post uses this to explain Jevons Paradox: making a resource cheaper or more efficient raises total use of it. The creator adds that users clearly preferred Luna over Terra.

Key points

• GPT 5.6 Terra and Luna were heavily discounted on OpenRouter.
• Token usage went up 13.8x after the discount.
• Jevons Paradox: when using a resource gets more efficient, total use goes up, not down.
• Users preferred Luna over Terra.
• Lesson for cost planning: cheaper tokens tend to mean more usage, so total spend may not drop.

Resources mentioned

• OpenRouter · tool · openrouter.ai · free
  A single OpenAI-compatible API that routes requests to hundreds of models from many providers, with one bill and model fallbacks.
  Also in: Customizing Your Coding Setup with Pi Coding Agent Extensions (Melvin Vivas on X · notes), The Jev model is now on OpenRouter (Melvin Vivas on X · notes), Kev-4B model, an alternative to Jev, now available on OpenRouter (Melvin Vivas on X · notes), Space Bunny Alpha: stealth 1M-context flash model on OpenRouter (Melvin Vivas on X · notes) and 42 more
• GPT 5.6 Luna · tool · openai.com · paid
  The OpenAI model used inside Codex for the demo. The transcript gives the variant name as 'Soul', which is unclear.
  Also in: Set Codex subagent model and reasoning to save usage limits (Melvin Vivas on X · notes), Use GPT-5.6 Luna in Codex for Terminal Tasks (Melvin Vivas on X · notes), Match Reasoning Effort to Task Length in Codex (Astra/Sol) (Melvin Vivas on X · notes), Run Coworker desktop agents cheaply with GPT-5.6 Luna on OpenRouter (Melvin Vivas on X · notes) and 24 more