The model also shows improved capabilities on a broad range of evaluations including reasoning and math: Claude Sonnet 4.5 is our most powerful model to date.

When we release new model snapshots, we migrate aliases to point to the newest version of a model, typically within a week of the new release. While aliases are useful for experimentation, we recommend using specific model versions (e.g., claude-sonnet-4-5-20250929) in production applications to ensure consistent behavior.

Pricing for Sonnet 4.5 starts at $3 per million input tokens and $15 per million output tokens, with up to 90% cost savings with prompt caching and 50% cost savings with batch processing. To learn more, check out our pricing page. To get started, simply use claude-sonnet-4-5 via the Claude API.

September 29, 2025 - This new model builds upon Claude 4’s foundation to achieve state-of-the-art performance in coding and complex agentic applications. Claude Sonnet 4.5 demonstrates advancements in agent capabilities, with enhanced performance in tool handling, memory management, and context processing.

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with improvements across system design, code security, and specification adherence.

Claude Sonnet 4.5 is our best model for building complex agents that can work independently for extended periods. It advances the frontier in coding capabilities, achieves state-of-the-art performance in computer use, and excels at powering ...

Claude Opus 4.5: Our most intelligent model combining maximum capability with practical performance. Features a more accessible price point than previous Opus models. Available with a 200k token context window.

Claude Sonnet 4.5 represents a major leap forward in AI capability and alignment. It is the most advanced model released by Anthropic to date, distinguished by dramatic improvements in reasoning, mathematics, and real-world coding. Supports 1m tokens of context.

Anthropic's mid-sized model for powering real-world agents, with capabilities in coding, computer use, cybersecurity, and working with office files like spreadsheets.

As our Anthropic colleagues tested the model before release, we heard remarkably consistent feedback. Testers noted that Claude Opus 4.5 handles ambiguity and reasons about tradeoffs without hand-holding. They told us that, when pointed at a complex, multi-system bug, Opus 4.5 figures out the fix.

5 days ago - GitHub placed Sonnet 4.5 in public preview for Copilot Chat and enabled it for the Copilot coding agent, soon after release. Anthropic stated that Sonnet 4.5 is its "most aligned frontier model" to date.

Claude Sonnet 4.5 is Anthropic's most capable model to date for building real-world agents and handling complex, long-horizon tasks, balancing the right speed and cost for high-volume use cases.

October 7, 2025 - You can invoke it via the API model name claude-sonnet-4-5 at the same token pricing as before ([2]). Claude Code 2.0 is rolling out with these features: updating the CLI tool (install or npm update claude) and the VS Code extension (beta) from ...

Google Cloud Console has failed to load JavaScript sources from www.gstatic.com. Possible reasons are:www.gstatic.com or its IP addresses are blocked by your network administratorGoogle has temporarily blocked your account or network due to excessive automated requestsPlease contact your network ...

September 29, 2025 - Starting today, Sonnet 4.5 is the default model for Augment Code, and will appear alongside GPT-5 in the model picker. Sonnet 4.5 delivers faster, more collaborative code generation and editing across all of our plans.

Computer use: Our best computer-using model yet, Claude Opus 4.5 navigates new experiences with confident, consistent approaches that deliver more human-like browsing, enabling better web QA, workflow automation, and advanced user experiences.

import requests import json # for getting a structured output with indentation response = requests.post( "https://api.aimlapi.com/v1/chat/completions", headers={ # Insert your AIML API Key instead of <YOUR_AIMLAPI_KEY>: "Authorization":"Bearer <YOUR_AIMLAPI_KEY>", "Content-Type":"application/json" }, json={ "model":"anthropic/claude-sonnet-4.5", "messages":[ { "role":"user", "content":"Hello" # insert your prompt here, instead of Hello } ] } ) data = response.json() print(json.dumps(data, indent=2, ensure_ascii=False))