GPT-6 Sol and GPT-6 Luna Are Live on Smart AIPI — 75% Off, Half the Cost of the 5.6 Family

Earlier this month OpenAI introduced GPT-6 Astra, its most intelligent and aligned model. The most demanding projects still call for Astra's full depth — but work happens at different scales, rhythms, and budgets. That's why OpenAI expanded the GPT-6 line with GPT-6 Sol and GPT-6 Luna, and both are on Smart AIPI right now at a quarter of OpenAI's price.

These models were trained with similar methods to Astra, carrying its advances in professional work, factuality, coding, computer use, and alignment into faster, more affordable tiers. The GPT-6 family leads across the cost–intelligence curve, and OpenAI passed the efficiency gains through by cutting Sol and Luna API prices 50% versus their GPT-5.6 promotional pricing. Smart AIPI passes its own 75% discount through on top of that.

The results that matter for developers

Sol and Luna are tuned for the cost–intelligence frontier, so every score below is worth reading next to its cost.

The scores only tell half the story — the other half is what they cost to reach.

Professional work

On AutomationBench (end-to-end business workflows across 47 tools spanning sales, marketing, operations, support, finance, and HR), GPT-6 Sol at xhigh effort hits 33.2% at $0.27 per task — outperforming Claude Opus 5 at max effort (26.9%) at roughly 9% of Opus 5's cost per task, and even beating low-effort GPT-6 Astra (30.3%). At high effort, GPT-6 Luna improves on its predecessor by 5.4 percentage points at 58% lower cost per task. On Agents' Last Exam, Sol at max effort scores 56.4%, above Claude Opus 5's highest score in the evaluation at 60% lower cost per task.

Coding

On DeepSWE v1.1 (original, long-horizon software-engineering tasks in real codebases), GPT-6 Sol at max effort scores 68.8% — within 1.1 points of Claude Fable 5's best in the evaluation (69.9% at xhigh) at approximately 80% lower cost per task. GPT-6 Luna at max effort scores 66.6%, comparable to Claude Opus 5 and Fable 5 at medium effort, while costing 93% less than Opus 5 and 96% less than Fable 5 per task. On FrontierCode, which grades not just correctness but mergeability (test quality, scope discipline, code style), Sol improves substantially over GPT-5.6 Sol and matches Claude Fable 5.1 xhigh at much lower cost.

Computer use

Astra remains the world's best model for computer use, but Sol and Luna are far more cost-efficient than their predecessors. On OSWorld 2.0 offline, GPT-6 Sol at xhigh reaches 60.5% — matching Claude Opus 5 at medium (60.3%) at roughly 80% lower cost per task. GPT-6 Luna at max effort exceeds GPT-5.6 Sol at medium at one tenth of its cost.

Factuality and alignment

On OpenAI's internal factuality evaluation — built from de-identified real conversations where users flagged mistakes — GPT-6 Sol makes about half as many mistakes as GPT-5.6 Sol, approaching Astra-level reliability at much lower cost. Luna improves substantially too. Both build on the alignment work introduced with Astra, showing improvements over their GPT-5.6 counterparts, including lower rates of misleading claims about their own coding work.

Pricing: 75% off, same models, same API

Smart AIPI charges 25% of OpenAI's list price. Here's the math for both models.

Both models also inherit GPT-6's improved prompt caching — higher default cache hit rates and a 90% discount on cached input reads — so agents and long conversations that reuse context get cheaper still. Same weights, same OpenAI-compatible API shape, same tools. The only difference is the invoice.

A cleaner collaboration style

Sol and Luna inherit Astra's improved communication style, most noticeable in technical and coding conversations: more clarity, less jargon, fewer odd turns of phrase, fewer low-value details, and slightly shorter answers without losing substance. In practice that means an agent that doesn't jump to conclusions, is more forthcoming about what it did and didn't check, and wastes fewer tokens restating the obvious.

How to use GPT-6 Sol and Luna

Chat Completions API

curl https://api.smartaipi.com/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-6-sol",
    "messages": [{"role": "user", "content": "Refactor this module and add tests"}]
  }'

Responses API with high reasoning

curl https://api.smartaipi.com/v1/responses \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-6-sol",
    "input": "Triage these open issues and open PRs to fix the top three",
    "reasoning": {"effort": "high", "summary": "auto"}
  }'

Codex CLI, Cursor, Cline, Roo Code, OpenCode, Aider

OPENAI_BASE_URL=https://api.smartaipi.com/v1
OPENAI_API_KEY=sk-your-smart-aipi-key
OPENAI_MODEL=gpt-6-luna

Reasoning effort supports low, medium, high, and xhigh. Sol and Luna scale meaningfully with effort — the AutomationBench, Agents' Last Exam, and OSWorld results above are all at higher effort settings. For long-horizon agentic work, use high or xhigh; for bulk throughput, low or medium on Luna is the cost-optimal default.

Which model should you actually run?

• gpt-6-astra — the best across the board. Choose it when you want the best results and an uncompromising experience: computer use, browser automation, long-horizon refactors where finishing unattended is the point.
• gpt-6-sol — difficult work at a fraction of frontier cost. Beats Claude Opus 5 on AutomationBench at ~9% of the cost and lands within a point of Fable 5 on DeepSWE at ~80% less. The right default for high-volume agentic coding and business automation.
• gpt-6-luna — the fast, cheap tier. Frontier-adjacent DeepSWE scores at 90%+ lower cost than Opus/Fable. Ideal for bulk work, classification, summarization, and high-throughput pipelines.

All three run on the same endpoint and the same key. Switching is a one-line change, so benchmark them on your workload rather than trusting anyone's chart — including this one.

Get started

1. Sign up at smartaipi.com/signup (free credits, no credit card)
2. Create an API key in the dashboard
3. Set your base URL to https://api.smartaipi.com/v1
4. Use model gpt-6-sol or gpt-6-luna

Astra-generation intelligence, tuned for cost, in production, at a quarter of the list price.