AI just took a major leap forward as Anthropic, the AI safety-focused startup founded by ex-OpenAI executives, unveiled the Claude 4 model family. This includes Claude 4 Opus and Claude 4 Sonnet. These next-generation models mark a bold stride into the future of intelligent systems, unlocking new possibilities for developers, enterprises, and everyday users alike.
So what’s all the buzz about? Think longer reasoning chains, unmatched coding skills, advanced tool use, and memory that actually remembers. The Claude 4 family isn’t just an incremental improvement, but a full-fledged transformation.
Let’s break it down.
What is Claude 4?
Claude 4 is Anthropic’s latest release in its Claude AI model series, following the successful Claude 3 family. This new generation comes in two main versions:
- Claude 4 Opus: A flagship, high-performance model
- Claude 4 Sonnet: A balanced, accessible model for general use
These models were unveiled at Anthropic’s first-ever developer conference, and they immediately impressed with benchmark-beating performance. Opus 4, for example, achieved state-of-the-art scores in complex reasoning, coding, and problem solving, outpacing rivals like GPT-4.1 and Google’s Gemini 2.5 Pro.
Whether you’re building software, analysing scientific research, or just want smarter digital assistance, Claude 4 promises to be a serious ally.
That said, here are five things to know about Claude 4.
Claude Opus 4 is a coding beast
If you work with code, Claude 4 Opus is about to become your new best friend. On industry-standard benchmarks, it’s outclassing every model in sight:
- 72.5% on SWE-bench (a top GitHub issue-solving benchmark)
- 43.2% on Terminal-bench, which tests terminal command-line understanding
When using parallel test-time computation, Claude Opus 4 achieves an even higher 79.4% on SWE-bench, and Sonnet 4 reaches 80.2%, putting them ahead of OpenAI’s best coding models (GPT-4.1 scores 54.6%). This cements Claude 4 as the current leader in software engineering tasks, though the advantage varies depending on implementation.
In practice, this means Claude can write, debug, and refactor production-grade code, even across multiple files and languages. It’s like pairing with a senior developer who never gets tired. Claude Opus can maintain high performance over long coding sessions up to 7 hours of continuous work. That’s a huge breakthrough for autonomous AI agents and next-gen developer tools.
Tool use + reasoning = Extended thinking
Claude 4 introduces a powerful new feature called “extended thinking,” which allows the model to access tools mid-conversation. This might include searching the web for real-time information, calling APIs, and executing code for complex calculations.
By toggling between reasoning and tool use, Claude becomes more like an autonomous assistant capable of researching, thinking, testing, and acting, all in one loop. This is a game-changer for developers, researchers, and businesses that want a truly intelligent co-pilot.
Claude 4’s hybrid architecture enables both rapid responses and “extended thinking” for complex tasks, allowing it to break down problems and work through multi-step solutions. Parallel tool execution means Claude can access multiple resources at once, boosting efficiency for demanding workflows.
Memory that actually works
A long-standing challenge in AI has been memory. Most chatbots forget everything once the conversation ends. Claude 4 changes that.
When granted file access or memory permissions, Claude can now retain key facts across sessions, recall previous conversations or documents, and build context over time for ongoing tasks.
Think of it like a digital colleague who actually remembers the project you’re working on — what you said last week, what’s pending today, and what’s changed since. That continuity unlocks far better productivity and personalisation.
Sonnet 4: Fast, smart, and now free
While Opus is the ultra-premium model, Sonnet 4 is no slouch. In fact, it replaces the previous Claude 3.5 Sonnet and delivers better performance across the board: sharper reasoning, cleaner code generation, and more accurate following of instructions
It is available to free users. You can access Claude Sonnet 4 right now at claude.ai, making cutting-edge AI accessible to millions. Whether you’re a student, startup founder, or hobbyist, Sonnet 4 gives you a powerful AI companion, no subscription needed.
Claude Sonnet 4’s free availability stands out, especially as OpenAI and Google typically reserve their most advanced models for paid users. This move could accelerate adoption among students, startups, and hobbyists, giving Anthropic a broader user base.
Developer tools got supercharged
Anthropic isn’t just releasing smarter models. They are building the ecosystem to support them. With the Claude 4 launch, they also introduced a suite of new developer tools via the Anthropic API:
- Code Execution: Let Claude run code and interpret results
- Files API: Upload and analyse large documents (PDFs, CSVs, and more)
- Prompt Caching: Reuse long prompts for up to one hour
- MCP Connector: Chain Claude with external tools and APIs
These tools make it easier than ever to build apps, agents, and automation powered by Claude. This is a clear push toward enabling smarter, self-directed AI systems.
Claude 4’s support for parallel tool execution and batch processing further enhances the developer ecosystem. This can significantly lower costs for high-volume users (up to 50% discount).
However, it’s important to note that Claude 4’s context window is capped at 200,000 tokens—substantial, but less than Google Gemini 2.5 Pro and OpenAI’s GPT-4.1, both of which now offer up to 1 million tokens (with Gemini planning to double this soon). Claude 4 may require additional workarounds, such as chunking or multiple API calls for applications requiring massive context, like analysing entire codebases or lengthy documents.
Meet the visionaries behind Claude 4
Anthropic was founded in 2021 by siblings Dario and Daniela Amodei, both former OpenAI executives who departed due to differing views on AI safety and governance. Dario, who previously served as OpenAI’s Vice President of Research, brings a deep technical background with a Ph.D. in biophysics and computational neuroscience from Princeton University. As CEO of Anthropic, he leads the company’s research and development efforts.
Daniela, serving as President, has a diverse background that includes roles in politics, global health, and technology, including a tenure at Stripe. At OpenAI, she was Vice President of Safety and Policy. Together, the Amodei siblings have assembled a team of experts from leading institutions like Google Brain, Baidu, and OpenAI, all committed to building AI systems that are safe, interpretable, and aligned with human values.
Anthropic’s unique focus on AI safety is embodied in Claude 4’s adoption of AI Safety Level 3 (ASL-3) protocols, the first time such comprehensive safety measures have been implemented in a production model. This includes Constitutional Classifiers and robust defences against jailbreaking, setting a new standard for responsible AI deployment.
Mounting investments
In recent times, Anthropic experienced significant investment activity, underscoring its prominence in the AI sector. In early 2024, Amazon completed a $4 billion investment, bringing its total stake to $8 billion and solidifying AWS as Anthropic’s primary cloud provider. Google also increased its commitment, investing over $1 billion, adding to its prior $2 billion investment.
By March 2025, Anthropic secured a $3.5 billion funding round led by Lightspeed Venture Partners, elevating its valuation to $61.5 billion. Other notable investors included Bessemer Venture Partners, Cisco Investments, D1 Capital Partners, Fidelity, General Catalyst, Jane Street, Menlo Ventures, and Salesforce Ventures.
These investments reflect growing confidence in Anthropic’s AI advancements, particularly its Claude models, and its emphasis on AI safety and interpretability. The company’s strategic partnerships and substantial funding position it as a formidable competitor to OpenAI in the evolving AI landscape.
A breakthrough moment for Anthropic
With Claude 4, Anthropic isn’t just keeping up with OpenAI and Google, but also eyeing to lead in critical areas like coding, tool use, and reasoning. Opus 4 offers elite-level AI performance for demanding enterprise and developer tasks, while Sonnet 4 makes advanced AI free and accessible to the masses. Add in tool use, real memory, and new dev features, and we have a serious AI platform to use in the future.
