GPT-5.6 Luna is a Fast/cheap from OpenAI (United States).
One-line fit: best used for High-volume cheap tasks.
Key specifications
| Provider | OpenAI |
|---|---|
| Model | GPT-5.6 Luna |
| Type | Fast/cheap |
| Context window | Large |
| Pricing (indicative) | $1 / $6 |
| Company category | Frontier Lab |
| Region | United States |
| Official site | https://openai.com |
Benchmarks and public standing
Strong good-enough throughput
Treat scores as directional. SWE-bench, Terminal-Bench, LMSYS Arena, Artificial Analysis, and vendor cards use different harnesses and are not always comparable 1:1. Re-check the latest official model card before decisions.
What this model is good at
High-volume cheap tasks
This aligns with OpenAI’s broader strengths:
- Agentic coding and computer-use
- Consumer chat and voice
- Enterprise ChatGPT distribution
- Multimodal generation
Limitations and watch-outs
Hard reasoning ceiling
- Rate limits, regional availability, and data retention policies vary by plan.
- Agent harness quality (Cursor, Claude Code, Codex, custom tools) can change outcomes more than raw model Elo.
- Open-weight availability (if any) is separate from hosted API quality and safety filters.
Ideal users
- Product engineers shipping features that match: High-volume cheap tasks
- Teams standardizing on the OpenAI ecosystem
- Agent builders who need a Fast/cheap
When to pick something else
- Cheaper volume: compare lower tiers from the same lab or open Chinese/EU alternatives.
- Maximum hard SWE thoughtfulness: compare Claude Fable-class and other coding flagships.
- Giant multimodal corpora / Workspace: compare Gemini-class models.
- Self-host / open weights: Llama, Qwen, DeepSeek, GLM, Mistral open lines.
Parent company
OpenAI – Consumer and enterprise AI leader behind ChatGPT, GPT flagship models, Codex, and GPT Live voice. Defines mass-market AI distribution.
Related models from OpenAI
- GPT-5.6 Sol – Flagship reasoning/agent
- GPT-5.6 Terra – Balanced
- o-series / reasoning lineage – Deliberative reasoning
- GPT-4o family – Multimodal chat
- Codex models – Coding agent backend
Data is curated for AIForumSphere model directory mid-2026 directional figures.
