Claude Sonnet 4.6 Is Here: What Anthropic's Latest Release Actually Means

Anthropic dropped Claude Sonnet 4.6 on February 17, 2026, less than two weeks after releasing Claude Opus 4.6. If the pace of releases feels relentless, that's because it is. The AI space is moving fast, and Anthropic is clearly not interested in letting competitors breathe.

Here's what you need to know about the new model and why it matters beyond the usual tech headline.

What Is Claude Sonnet 4.6?

Claude Sonnet 4.6 is Anthropic's mid-tier model, sitting between the budget-friendly Haiku and the premium Opus in the company's model lineup. It is now the default model for all Claude users, including free tier accounts. That means anyone using Claude at claude.ai is now running Sonnet 4.6 without paying a dime more.

The model is priced identically to its predecessor, Sonnet 4.5, at $3 per million input tokens and $15 per million output tokens. The cost stayed the same. The performance did not.

The Big Upgrades

Anthropic describes Sonnet 4.6 as a full upgrade across coding, computer use, long-context reasoning, agent planning, knowledge work, and design. That covers a lot of ground, but a few areas stand out.

Computer use is the headline capability. The model scored 72.5 on the OSWorld-Verified benchmark, compared to 28.0 for Sonnet 3.7 roughly a year ago on a precursor benchmark. That is a dramatic improvement in AI's ability to navigate software interfaces, fill out forms, coordinate across browser tabs, and complete multi-step tasks the way a human would. Anthropic is clear that the model still falls short of the most skilled humans at computer use, but the trajectory is hard to ignore.

Coding is the other major story. Sonnet 4.6 hits 79.6% on the SWE-bench Verified benchmark, outpacing GPT-5.2 at 77.0% and outperforming the previous Sonnet 4.5 by a meaningful margin. Claude Code users, who can use the model for agentic coding tasks from the terminal, reportedly prefer Sonnet 4.6 over 4.5 at a 70% rate after direct comparison testing.

The model also introduces a 1 million token context window in beta, making it significantly easier to work with large codebases, lengthy documents, and complex research tasks in a single session.

Where Sonnet 4.6 Stacks Up Against Opus 4.6

This is where things get interesting for businesses making decisions about which model tier to pay for. Sonnet 4.6 actually outperforms Opus 4.6 in two of 13 benchmark categories: office tasks (1,633 vs. 1,606 Elo) and financial analysis (63.3% vs. 60.1% on Finance Agent v1.1). Opus still leads in reasoning-heavy tasks, but at one-fifth the cost, Sonnet 4.6 is the better value for most business workflows.

The Security Angle

More capable computer use also raises legitimate security concerns. When an AI model can fill out forms, navigate interfaces, and complete multi-step tasks autonomously, the risk of prompt injection attacks, where malicious content tricks the model into taking unintended actions, becomes a real issue.

Anthropic addressed this directly. The company reports that Sonnet 4.6 is a major improvement over Sonnet 4.5 in resistance to prompt injection attacks, performing at a similar level to Opus 4.6 on safety evaluations. They also recommend layered defenses, including using the lightweight Haiku 4.5 model to pre-screen inputs before they reach the main model.

What This Means for Businesses Using AI

The broader picture here is that the gap between mid-tier and flagship AI models is closing fast. Capabilities that required premium pricing six months ago are now shipping as the default free experience. For marketing teams, agencies, and operations professionals, that means the business case for AI-assisted work gets stronger with each release cycle.

The software industry is already feeling the pressure. The iShares Expanded Tech-Software Sector ETF has dropped over 20% year to date, driven in part by concern that AI agents are going to disrupt traditional software workflows. Sonnet 4.6's computer use improvements are precisely the kind of development fueling that concern.

At AdToro, we work across multiple industries helping brands understand how AI fits into their content, SEO, and digital marketing strategies. Releases like this one matter not just as tech news but as signals about where human-assisted and AI-assisted workflows are headed. If an AI model can navigate a browser, complete multi-step tasks, and outperform a flagship model on office productivity, the definition of "knowledge work" is shifting in real time.

Anthropic's rate of progress is the real story here. Two major model releases in under two weeks, each with meaningful real-world improvements, sets a pace that every business with a digital footprint should be paying attention to.