-
1
Claude Mythos 5.1
Anthropic
Unlock advanced capabilities for cybersecurity and scientific breakthroughs.
Claude Mythos 5.1 signifies the latest evolution in the Mythos series of models developed by Anthropic, specifically designed for advanced applications across fields such as cybersecurity, biology, scientific research, programming, and extensive knowledge-intensive tasks. Although it is built on the same core architecture as Claude Fable 5.1, it stands out due to its distinct safety protocols: while Fable 5.1 is broadly available, Mythos 5.1 is restricted to select trusted access initiatives that incorporate specialized safeguards for cybersecurity and life sciences. This model sets a new standard for performance in autonomous coding and exhibits unmatched cyber capabilities compared to all previous Anthropic models. In the scientific research domain, Mythos 5.1 adeptly manages specialized tools and complex workflows related to molecular design, computational biology, and other technical disciplines. During Anthropic's evaluation, it successfully designed high-affinity protein binders for various targets, achieving its highest hit rate to date. Furthermore, it excelled in optimizing seven distinct open-source deep learning models that focus on protein and genomics. By advancing the limits of what can be accomplished, Mythos 5.1 is poised to play a pivotal role in shaping future research and development projects, ultimately influencing a wide array of scientific inquiries and technological innovations. Its capabilities suggest a transformative impact on how complex biological and computational problems are approached in the coming years.
-
2
Claude Opus 5
Anthropic
Empower your projects with intelligent, efficient AI solutions.
Claude Opus 5 is Anthropic’s advanced Opus model designed for high-value coding, knowledge work, problem-solving, automation, scientific research, and everyday AI workflows. The model is positioned as a thoughtful and proactive system that approaches the frontier intelligence of Claude Fable 5 at half the price. Anthropic says Claude Opus 5 delivers greatly improved performance for the same cost as Opus 4.8, with base pricing of $5 per million input tokens and $25 per million output tokens. The model supports effort settings that allow customers to optimize for deeper intelligence or conserve tokens for faster and cheaper results. Claude Opus 5 performs especially well on software engineering evaluations, including tasks that require debugging, code generation, root-cause analysis, test creation, and multi-step implementation. It also shows strong results on knowledge work, business automation, computer use, novel problem solving, and research-heavy tasks. Anthropic highlights that Opus 5 is better at checking its own work, iterating until it succeeds, and building supporting tools when a task requires it. The model improves on Opus 4.8 across life sciences evaluations, including structural biology, organic chemistry, bioinformatics, molecular structure inference, and protein function tasks. Claude Opus 5 includes alignment and safety protections that aim to allow beneficial cybersecurity and biology use cases while restricting riskier exploit generation, penetration testing, and certain autonomous misuse scenarios. It is available on Claude Max as the default model, on Claude Pro as the strongest model, and through the Claude API as claude-opus-5, with a Fast mode that runs around 2.5 times the default speed.
-
3
Grok 4.5
SpaceXAI
Transform coding and productivity tasks with advanced AI efficiency.
Grok 4.5 is an advanced AI model from SpaceXAI built for coding, agentic tasks, engineering workflows, and knowledge work. It is presented as SpaceXAI’s strongest model to date and is designed to perform well on real-world software engineering tasks rather than only short benchmark prompts. The model was trained on datasets spanning coding, science, engineering, and math, with heavy investment in data filtering, deduplication, quality scoring, and domain-focused selection. Its reinforcement learning process focuses on multi-step software engineering, technical problem solving, automated grading, model-based evaluation, and long-running agentic rollouts. Grok 4.5 can work on challenging development tasks across languages and environments, including Rust, C/C++, terminal workflows, debugging, bug fixing, and end-to-end app generation. The model is also capable of building polished applications from a single prompt, such as interactive simulations, modern interfaces, and functional web experiences. In addition to coding, Grok 4.5 supports knowledge work inside Grok Build, including Excel model creation, web research, multi-sheet formulas, PowerPoint slide design, native diagram creation, and Word document drafting. It is designed for speed and efficiency, with fast serving, strong token efficiency, and pricing based on input and output token usage. Developers can access Grok 4.5 through the SpaceXAI API console, Cursor, and Grok Build, making it usable across coding tools, productivity environments, and custom applications. The model is positioned for teams that need intelligent technical execution at a lower cost and with fewer steps than some competing frontier models. By combining engineering-focused training, agentic reasoning, fast inference, office productivity skills, and broad developer access, Grok 4.5 gives users a capable model for building, automating, debugging, researching, and shipping complex work.
-
4
Claude Fable 5
Anthropic
Empowering professionals with advanced AI for complex tasks.
Claude Fable 5 is a frontier AI model developed by Anthropic to deliver advanced reasoning, coding, research, and multimodal capabilities for enterprise and professional users. As a Mythos-class model adapted for broad availability, it combines high-level intelligence with safety-focused deployment controls. The model excels at software engineering tasks, including large-scale code analysis, migrations, debugging, architecture review, and autonomous project execution. Claude Fable 5 also demonstrates strong performance in knowledge work, helping users analyze documents, evaluate financial information, interpret charts and tables, conduct research, and generate actionable insights. Its vision capabilities enable sophisticated image understanding, visual reasoning, and screenshot-based analysis. The model supports long-context workflows and persistent memory utilization, allowing it to work effectively on extended tasks involving millions of tokens of information. Anthropic has implemented a layered safety framework that includes specialized classifiers for cybersecurity, biology, chemistry, and model distillation-related requests. When these areas are detected, requests may be handled by a different model with stricter operational controls. Claude Fable 5 is available through the Claude API and Anthropic’s product ecosystem, providing developers and enterprises with access to advanced AI-powered assistance. The model is designed to enhance productivity, accelerate research, improve software development workflows, and support complex analytical tasks. By combining powerful reasoning, multimodal intelligence, and enterprise-focused safeguards, Claude Fable 5 enables organizations to scale AI adoption responsibly and effectively.
-
5
Claude Sonnet 5
Anthropic
Unlock productivity with advanced AI for every task.
Claude Sonnet 5 is Anthropic's latest AI model engineered to deliver highly capable agentic performance for developers, enterprises, and organizations building next-generation AI applications. The model expands the capabilities of the Sonnet family by enabling autonomous planning, browser interaction, terminal usage, tool calling, coding assistance, and complex reasoning while remaining significantly more affordable than larger AI models. Anthropic designed Sonnet 5 to close much of the performance gap between previous Sonnet releases and the company's Opus models, offering major improvements in coding, knowledge work, reasoning, and long-running autonomous tasks. The model demonstrates stronger performance across numerous benchmark evaluations while also improving safety through lower hallucination rates, reduced sycophancy, improved refusal of malicious requests, and greater resilience against prompt injection attacks. Anthropic notes that Sonnet 5 also has substantially lower cybersecurity capabilities than its most advanced Opus models, reducing certain categories of misuse risk while still supporting legitimate development work. Developers can access Sonnet 5 through every Claude subscription tier, Claude Code, and the Claude API using introductory token pricing before standard pricing takes effect. The API allows organizations to integrate Sonnet 5 into production software while selecting different effort levels to optimize cost, latency, and capability for individual workloads. Anthropic also increased platform rate limits to support the higher token usage associated with advanced agentic workflows. Safety safeguards for cybersecurity-related requests are enabled by default, reflecting the model's improved autonomous capabilities while maintaining appropriate protections.