Update
This was indeed "Grok Code Fast", by xAI.
Overview
Cline has added a new model, referred to as “Sonic,” in a stealth release. According to the announcement, Sonic offers a 262k context window and is entirely free to use while in alpha, with no usage limits and no tiered pricing. The post describes the model as built for coding, oriented toward iterative, autonomous development workflows. Access is provided through the Cline provider identifier cline:cline/sonic.
The announcement was published by Nick Baumann on August 20, 2025, with the note that usage during the alpha period will help refine the model’s development. The post is available at https://cline.bot/blog/new-stealth-model-in-cline-sonic and includes an image as well as Baumann’s social handle: @nickbaumann_.
What’s stated
Sonic’s headline characteristic is its 262k context window, positioned for scenarios where larger in-session context is relevant. The post frames the model’s purpose as “built for coding,” emphasizing iterative and autonomous development cycles rather than general-purpose tasks. The alpha period is described as free to use without restrictions, which includes the absence of usage caps and pricing tiers during this phase.
From an access standpoint, the provider string is explicitly documented as cline:cline/sonic, indicating where it can be selected within Cline’s model options. No further integration steps are outlined in the announcement.
What’s not specified
Beyond the context window size and usage terms during alpha, the post does not provide technical details such as model architecture, training data, evaluation results, or latency characteristics. It does not state any post-alpha pricing, availability timeline after the alpha period, or regional availability constraints. No comparative benchmarks versus other Cline models or third-party models are included. Aside from the focus on iterative, autonomous software development, additional capability descriptions are not provided.
Access and availability
- Availability: The announcement is live as of August 20, 2025. The model is described as in a “stealth” and “alpha” state.
- Access method:
cline:cline/sonicvia the Cline provider. - Cost during alpha: Free, with no usage limits and no tiered pricing.
- Post-alpha details: Not disclosed.
TL;DR
- New stealth model “Sonic” added to Cline
- 262k context window
- Built for coding and iterative, autonomous development workflows
- Free during alpha, with no usage limits or tiers
- Access via
cline:cline/sonic - No architecture, benchmarks, or post-alpha pricing disclosed
