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Replit Adds GPT-6.1 Sol and Claude Sonnet 5.5 to Agent

ReplitView original changelog

Replit added two new model options to Agent: GPT-6.1 Sol, selectable in Max mode, and Claude Sonnet 5.5, selectable in Power mode. The release gives developers a newer OpenAI and Anthropic model to pick from when building with Agent. Replit also published a blog post explaining its philosophy on model selection.

Key Takeaways

  • GPT-6.1 Sol is now selectable in Max mode, giving Agent users the newest OpenAI model for demanding builds.
  • Claude Sonnet 5.5 arrives in Power mode, adding a current Anthropic option to Replit's higher-capability tier.
  • Models are tied to Agent modes rather than a separate picker, so choosing a mode is how developers choose a model.
  • Replit's "Free the Models" post argues that the model should decide when to delegate and at what effort level, instead of a router.
  • The release continues Replit's pattern of adding new frontier models within days of launch, following the late-September GPT-6 Sol and Opus 5.5 additions.
  • The changelog gives no pricing or plan details, so developers should check the in-product model list for what their account can use.

New Models in Agent

Replit expanded the list of models that power Agent. Developers can now choose GPT-6.1 Sol when working in Max mode and Claude Sonnet 5.5 when working in Power mode. Both appear in the model options Replit exposes for Agent, so no new setup is required beyond picking the model.

GPT-6.1 Sol in Max mode

GPT-6.1 Sol is the newest OpenAI option in Agent, and Replit places it in Max mode. That mode is aimed at the hardest and most demanding build tasks. It follows the earlier addition of GPT-6 Sol and GPT-6 Luna Fast to the same lineup in late September.

Claude Sonnet 5.5 in Power mode

Claude Sonnet 5.5 joins Power mode, the mode Replit points to for the most capable standard builds. It sits alongside the other Anthropic models already available in Agent, which gives developers a fast Sonnet-class option in the higher-capability tier.

Why Replit Offers a Choice of Models

Alongside the release, Replit published a blog post titled "Free the Models" that describes its approach to model selection. In Replit's account, the model itself can decide when to delegate work, at what effort level and to which specialist, instead of a separate router choosing the model. The post describes effort levels from low to max that can be adjusted during a turn. The model additions in this release fit that approach, because each new frontier model is made available inside Agent without requiring a separate workflow.

Availability

The changelog lists the models by mode and does not give pricing or plan details. Replit's own model list inside the product remains the source of truth for what a given account can select.