Claude Sonnet 4.5: What's New and Why It Matters

<p><strong>Claude Sonnet 4.5</strong> focuses on three pillars: reasoning depth, coding accuracy, and long-context reliability. Beyond headline benchmarks, we tested real-world workflows.</p> <h2>Highlights</h2> <ul> <li><strong>Reasoning:</strong> Better chain-of-thought and fewer dead ends on complex instructions</li> <li><strong>Coding:</strong> Higher pass rates on repo-scale tasks and test-first debugging</li> <li><strong>Context:</strong> More stable outputs across long, iterative sessions</li> </ul> <h2>Developer Takeaways</h2> <ol> <li>Use 4.5 for longer refactors and cross-file analysis</li> <li>Leverage tool use (function calling, retrieval) for reliability</li> <li>Combine with a fast model for summaries and pre-processing</li> </ol> <p>Check current pricing and tiers on our <a href="/models">models page</a>. Use the <a href="/">Token Calculator</a> to compare cost-per-request at your typical token counts.</p>