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Anthropic released a new AI model, Claude Sonnet 4.5, with stronger coding abilities and new features to streamlines the process.
It's "the best coding model in the world," Anthropic says. The company also also referred to its last model as "the world's best" for coding. But, unsurprisingly, it says the newest one is a cut above.
A major new feature is "checkpoints," which allows programmers to save their progress and revert to a previous version. Other additions include a new terminal interface, context adjusting capabilities, and file creation (spreadsheets, slides, and documents) without leaving the chat window, which is now available with all paid plans.
Developers can create their own AI agents using the Claude Agent SDK. "The infrastructure that powers our frontier products—and allows them to reach their full potential—is now yours to build with," says Anthropic.
In the company's internal evaluations, Sonnet 4.5 earned a score of 77.2% on the "agentic coding," or self-directed coding, test. That's compared to a slightly lower 74.5% for its predecessor Opus 4.1 and Codex, the programming tool within OpenAI's GPT-5. But remember, these are internal benchmarks. It's always worth trying multiple tools to find the one that's best for you.
Happily, Anthropic did not increase the price of Sonnet 4.5 through the developer API, which remains the same as Sonnet 4, at $3/$15 per million tokens.
Beyond coding, Anthropic is positioning Claude as the go-to chatbot for all workplace tasks. That differentiates it from ChatGPT, which is used for non-work-related conversations over 70% of the time, according to an OpenAI study released this month. Anthropic lists financial services, cybersecurity, and law as other fields its chatbot excels in.
Claude Sonnet 4.5 "creates presentations, spreadsheets, and PDFs you'd actually be proud to share with your boss or clients and sharpens your thinking on complex problems," Anthropic says.
The AI can even use your computer for you, performing simple tasks like navigating websites and filling out spreadsheets. It works in Google Chrome with an extension, which is now available for those with a Max plan ($100 to $200-per-month) to sign up for through a waitlist.
However, these capabilities are still nascent and flawed, just like agentic coding. Anthropic says it bolstered Claude's defenses against prompt injection attacks when in computer use mode, a type of cyberattack that represents "one of the most serious risks."
Claude, like all chatbots, can also be kind of a jerk. It's prone to "sycophancy, deception, power-seeking, and the tendency to encourage delusional thinking," in certain scenarios. It's known to do things like "praise obviously-terrible business ideas" and confirm to users that they are indeed the Matrix, according to the system card for Sonnet 4.5.
Anthropic says Sonnet 4.5 is its least likely model to engage in these behaviors, and that it expects it to be "much more direct and much less likely to mislead users than any recent popular large language model (LLM)." When OpenAI and Anthropic evaluated each other's models over the summer, OpenAI reported Claude was less likely to engage in sycophantic and harmful behaviors than ChatGPT.
Over the past year, Claude has emerged as a favorite LLM among individuals and businesses (not book authors). Apple and Meta reportedly use Claude internally, TechCrunch reports. You may start to see Anthropic advertisements on streaming platforms like Netflix and Hulu, and at live sporting events as well since company launched its first major advertising campaign this fall, AdWeek reports.