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GPT-5.6 on Felo AI: OpenAI's Newest Model Family, Now Free to Try

· 5 min read
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OpenAI's GPT-5.6 family — Sol, Terra, and Luna — brings stronger reasoning and a 400K token context window. Felo Pro subscribers try it free for 7 days.

GPT-5.6 AI Model Capabilities

OpenAI just released GPT-5.6 — and it is not one model but three: Sol, Terra, and Luna. Felo AI now runs the full GPT-5.6 family inside its search and reasoning pipeline, and Felo Pro subscribers can try it free for 7 days.

✅ Try GPT-5.6 for Free on Felo AI Search

This is the first time OpenAI has organized a release around durable tiers instead of shipping a single "best model." Here's what each tier does, what makes the family different, and how to use it today on Felo AI.

What Makes GPT-5.6 Different​

GPT-5.6 isn't an incremental update over GPT-5.5. It's a generational jump built around three dimensions: model choice, reasoning depth, and cost efficiency.

Three Tiers, Not One Model​

  • Sol — the flagship. Built for serious coding, multi-step reasoning, agentic workflows, and cybersecurity. It introduces a new max reasoning effort and an ultra mode that deploys subagents for complex tasks.
  • Terra — the balanced tier. Roughly as good as GPT-5.5 at about half the cost. The right choice for most everyday work.
  • Luna — the fast tier. For high-volume tasks where speed and cost matter more than peak reasoning.

Instead of asking "which model is smartest," the tier system asks "which model fits this job" — a meaningfully different way to think about model selection.

400K Token Context Window​

GPT-5.6 ships with a 400K token context window, enough to hold entire codebases, long PDFs, meeting transcripts, and technical references in a single session without losing the thread.

Competitive, Efficient Reasoning​

Independent benchmarking from Artificial Analysis found GPT-5.6 Sol scoring just 1 point behind Claude Fable 5 on their Intelligence Index — at roughly one-third of the cost. That shift changes the calculus for anyone running AI agents at scale: overnight batch processing, 24/7 support agents, and real-time document analysis all get more economical.

Stronger Agentic Coding​

Sol was built with agentic workflows in mind. It set a new record on Terminal-Bench 2.1 for command-line tasks that require planning, iteration, and tool coordination. Long-running coding tasks, multi-file refactors, and complex debugging sessions all benefit from the expanded context window and improved instruction-following.

What You Can Build With GPT-5.6​

🖥️ Full-Codebase Analysis​

With a 400K token window, you can feed large parts of a repository at once. Ask questions about architecture, find bugs across modules, or generate documentation that accounts for the broader system.

📊 Enterprise Document Processing​

Long contracts, compliance documents, and financial reports in a single request, with far less chunking and far less context loss than older models.

🌐 Multilingual Research at Scale​

Felo AI's multilingual capabilities combined with GPT-5.6's context window mean you can research across languages, documents, and sources in a single session. Cross-border due diligence, international market analysis, multilingual content creation — all without switching tools.

🧑‍💻 Coding and Debugging Workflows​

Plan, iterate, and debug with a model that understands repository-level context and coordinates tools as work unfolds — Sol's strongest area.

How to Use GPT-5.6 on Felo AI — Right Now​

Felo AI has integrated the full GPT-5.6 family into its search platform. The 7-day free trial is available exclusively to Felo Pro subscribers — no credit card required beyond your existing Pro plan.

Getting started takes about a minute:

  1. Go to felo.ai/search?search_model=gpt-5-6-sol
  2. Sign in (or subscribe to Felo Pro if you haven't yet)
  3. Select the GPT-5.6 tier you want — Sol, Terra, or Luna
  4. Start prompting

The tool supports the full range of GPT-5.6 capabilities: text, long-context analysis, and agentic coding. Whether you're debugging code or analyzing documents, the interface adapts to your workflow.

Why Felo AI?​

Felo AI is a multilingual AI productivity platform headquartered in Tokyo. Its core strength — multi-language capability from search to creation — pairs naturally with a model family built for long-context, multi-step work.

The platform gives Felo Pro subscribers access to GPT-5.6 alongside other leading models, making it easy to compare outputs and pick the right tier for each task.

For teams working across languages and borders, Felo AI + GPT-5.6 means one platform for research, analysis, and content creation — in any language.

The Bottom Line​

GPT-5.6 brings three purpose-built tiers — Sol, Terra, and Luna — a 400K token context window, and benchmark results that hold up against top competitors at a fraction of the cost.

Felo Pro subscribers can try the full family free for 7 days, starting now.

Try GPT-5.6 on Felo AI → felo.ai/search?search_model=gpt-5-6-sol

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