Anthropic unveils Claude Sonnet 4.5 with coding, agent SDK, and app upgrades
Claude Sonnet 4.5 delivers stronger coding benchmarks, new developer tools, and app upgrades, with Anthropic staff sharing highlights in LinkedIn posts.
Anthropic has launched Claude Sonnet 4.5, its latest large language model AI for coding and agentic tasks.
Alex Albert, Head of Developer Relations at Anthropic, emphasized the model’s capabilities in a LinkedIn post: “Introducing Claude Sonnet 4.5 – the best coding model in the world and the strongest model for building complex agents. Sonnet 4.5 leads on SWE-bench Verified and can maintain focus for more than 30 hours on complex, multi-step tasks.”
Claude Sonnet 4.5 leads on benchmarks such as SWE-bench Verified and OSWorld, which test coding performance and computer-use tasks. According to Anthropic, the model can remain focused for more than 30 hours on complex problems, while also showing improvements in reasoning and math.
Albert added: “We’re also releasing the Claude Agent SDK—the same infrastructure that powers Claude Code—so developers can build agents with the same foundation we use.”
Claude platform gets major upgrades
The launch was accompanied by upgrades across the Claude platform. Claude Code now includes checkpoints, a refreshed terminal, and a native Visual Studio Code extension. The Claude API introduces context editing and memory tools for longer-running agents.
Claude apps now support code execution and file creation within conversations, covering spreadsheets, slides, and documents. In addition, the Claude for Chrome extension has started rolling out to Max subscribers on the waitlist.
Anthropic has also introduced the Claude Agent SDK, which it describes as the same infrastructure used to build Claude Code, now available for developers to create their own agents.
Nicole Sim, Product Marketing at Anthropic, wrote in her own post: “Another big day at Anthropic! We just shipped Claude Sonnet 4.5: best coding model in the world (yet again). And somehow also managed to ship major upgrades across every product at once.”
Sim pointed to the combined release: “In one release: Claude Code gets checkpoints, a native VS Code extension, and a refreshed terminal; Claude API adds new context editing and memory tools; Claude apps now have code execution and file creation built directly into conversations; Claude for Chrome extension rolls out to Max users who joined the waitlist; Claude Agent SDK … is now available to all developers.”
She concluded: “And if you're a Max user, don't miss the 5-day research preview at claude.ai/imagine. Claude generates software on the fly. It's a genuinely fun peek into what's possible!”
