GBrain now offers nine new models from Anthropic and OpenAI, and Claude Opus 5.5 is the default.
Four of them cost less than the models they replace
Claude Opus 5.5 is the default for new workspaces, and every workspace that ran Opus 4.8 or Opus 5 now runs it. Anthropic says it performs at the level of Claude Fable 5.1 on most work. It costs $4 per million input tokens and $20 per million output tokens, a fifth less than Opus 4.8 and Opus 5 ($5 and $25).
OpenAI describes GPT-6.1 Sol as built for complex coding and professional work, at a lower cost than GPT-6 Astra. At $2 in and $10 out, it costs less than GPT-5.5 ($5 and $30) on every rate, and it is now listed first among OpenAI’s models.
GPT-6 Luna is the lowest-priced GPT-6 model, at $0.10 in and $0.50 out, for high-volume work.
Claude Sonnet 5.5 runs 30% faster than Sonnet 5 and costs up to 30% less, by Anthropic’s measure.
Two models for the hardest work
Claude Fable 5.1 and GPT-6 Astra are the most capable models GBrain offers from each company. They cost more than the models above.
Every new model
| Model | From | Per million tokens, in / out |
|---|---|---|
| Claude Opus 5.5 | Anthropic | $4 / $20 |
| Claude Fable 5.1 | Anthropic | $10 / $50 |
| Claude Sonnet 5.5 | Anthropic | $2 / $10 |
| GPT-6.1 Sol | OpenAI | $2 / $10 |
| GPT-6 Astra | OpenAI | $10 / $50 |
| GPT-6 Sol | OpenAI | $2 / $10 |
| GPT-6 Luna | OpenAI | $0.10 / $0.50 |
| GPT-5.6 Terra | OpenAI | $2 / $12 |
| GPT-5.6 Luna | OpenAI | $0.20 / $1.20 |
Each model’s page has its cached-input price too. “GPT-5.6” is now listed by its full name, GPT-5.6 Sol.
What you might notice
Answers from Opus 5.5. A workspace that ran Opus 4.8 or Opus 5 now answers with Opus 5.5. A workspace that chose any other model keeps it.
What you need to do
Nothing. An admin can choose a different model on the workspace’s Model page, under Settings.
The announcements are Anthropic’s posts on Claude Opus 5.5, Claude Sonnet 5.5 and Claude Fable 5.1, and OpenAI’s model changelog.