List of the Top AI Reasoning Models for Mimasa AI in 2026

Claude Fable 5.1 is an advanced general-purpose AI model from Anthropic focused on coding, scientific research, knowledge work, business processes, and long-horizon agentic reasoning. It is the generally available counterpart to Claude Mythos 5.1, which uses the same underlying model but is offered with different safeguards for vetted cybersecurity and life sciences users. Compared with Claude Fable 5, Fable 5.1 shows stronger performance across agentic coding, research, computer use, multidisciplinary reasoning, business workflow automation, and other complex benchmarks. The model is designed to remain effective during long-running tasks that involve planning, tool use, repeated verification, code modification, research, and multi-step decision making. In software engineering scenarios, it can investigate difficult bugs, trace problems across large codebases, perform code review, and work through complex implementation tasks with less supervision. Anthropic also positions Fable 5.1 as a stronger research model, with demonstrated capabilities in scientific analysis, computational modeling, and other technically demanding workflows. Improvements to cache-read pricing reduce the cost of reusing previously processed context, making the model more economical for workflows that involve long conversations, large codebases, or repeated tool calls. Fable 5.1 introduces updated enterprise privacy and security options, including Enterprise Frontier Safeguards and zero-data-retention access for eligible customers during the rollout period. Its cybersecurity protections are designed to permit more benign defensive security work, including vulnerability discovery, while continuing to restrict higher-risk activities such as exploit development and certain penetration-testing tasks. The model is available through Claude.ai, Claude Code, Claude Cowork, the Claude API, Amazon Web Services, Google Cloud, and Microsoft Azure under the claude-fable-5-1 model identifier for API users.

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.

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.

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.

GPT-5.5 represents a new class of AI built to transform how work is done across digital environments. It combines advanced reasoning, tool usage, and task execution capabilities to manage complex, multi-step workflows with minimal human intervention. The model performs strongly in software engineering, data analysis, business operations, and scientific research, where it can plan tasks, gather information, test solutions, and refine outputs iteratively. It supports generating documents, building applications, analyzing large datasets, and navigating software systems as part of a unified workflow. A key capability is its integration with workspace agents—customizable AI agents that can be created once and deployed across teams to automate entire processes. These agents can run continuously, interact with tools like CRM systems, messaging platforms, and document editors, and keep workflows moving without constant supervision. Organizations can define permissions, approval checkpoints, and monitoring to maintain full control over automation. GPT-5.5 also improves collaboration by standardizing workflows and scaling best practices across teams. With enterprise-grade security and governance, it is designed for safe deployment in complex environments. Its ability to persist through ambiguity and long-running tasks makes it highly effective for execution-heavy work. By reducing manual intervention and increasing speed, GPT-5.5 enables teams to focus on higher-value activities and operate at a significantly higher level of productivity.

Perplexity Research is an advanced AI-driven platform designed for thorough investigations into a wide array of complex subjects. By emulating human research techniques, it methodically examines, analyzes, and interprets different documents while constantly enhancing its approach to achieve a profound understanding of the topic at hand. Once the research process is complete, Deep Research organizes the amassed information into detailed reports, which users can easily export as PDFs or share online. This innovative tool is particularly valuable across various sectors, including finance, marketing, technology, health, and travel planning, empowering users to conduct professional-level research with exceptional efficiency. At present, Deep Research is accessible online, with plans to broaden its availability to iOS, Android, and Mac platforms in the future, providing free access with unlimited queries for Pro subscribers and imposing daily limits for non-subscribers. Furthermore, the intuitive interface is designed to ensure that even those with little experience can navigate the platform effortlessly and take advantage of its sophisticated capabilities. The versatility and user-centric design of Deep Research make it an indispensable asset for anyone looking to dive deep into research across multiple domains.

OpenAI’s GPT-5 is the latest flagship AI language model, delivering unprecedented intelligence, speed, and versatility for a broad spectrum of tasks including coding, scientific inquiry, legal research, and financial analysis. It is engineered with built-in reasoning capabilities, allowing it to provide thoughtful, accurate, and context-aware responses that rival expert human knowledge. GPT-5 supports very large context windows—up to 400,000 tokens—and can generate outputs of up to 128,000 tokens, enabling complex, multi-step problem solving and long-form content creation. A novel ‘verbosity’ parameter lets users customize the length and depth of responses, while enhanced personality and steerability features improve user experience and interaction. The model integrates natively with enterprise software and cloud storage services such as Google Drive and SharePoint, leveraging company-specific data to deliver tailored insights securely and in compliance with privacy standards. GPT-5 also excels in agentic tasks, making it ideal for developers building advanced AI applications that require autonomy and multi-step decision-making. Available across ChatGPT, API, and developer tools, it transforms workflows by enabling employees to achieve expert-level results without switching between different models. Businesses can trust GPT-5 for critical work, benefiting from its safety improvements, increased accuracy, and deeper understanding. OpenAI continues to support a broad ecosystem, including specialized versions like GPT-5 mini and nano, to meet varied performance and cost needs. Overall, GPT-5 sets a new standard for AI-powered intelligence, collaboration, and productivity.

The newest version in the GPT-5 lineup, referred to as GPT-5.1, seeks to greatly improve the cognitive and conversational skills of ChatGPT. This upgrade introduces two distinct model types: GPT-5.1 Instant, which has become the favored choice due to its friendly tone, better adherence to instructions, and enhanced intelligence; conversely, GPT-5.1 Thinking has been optimized as a sophisticated reasoning engine, facilitating easier comprehension, faster responses for simpler queries, and greater diligence when addressing intricate problems. Moreover, user inquiries are now smartly routed to the model variant that is most suited for the specific task, ensuring efficiency and accuracy. This update not only enhances fundamental cognitive abilities but also fine-tunes the style of interaction, leading to models that are more pleasant to engage with and more in tune with user desires. Importantly, the system card supplement reveals that GPT-5.1 Instant features a mechanism called "adaptive reasoning," which helps it recognize when deeper contemplation is warranted before crafting its reply, while GPT-5.1 Thinking precisely tailors its reasoning duration based on the complexity of the question asked. These innovations signify a considerable leap in the quest to make AI interactions more seamless, enjoyable, and user-centric, paving the way for future developments in conversational AI technology.

GPT-5.2 ushers in a significant leap forward for the GPT-5 ecosystem, redefining how the system reasons, communicates, and interprets human intent. Built on an upgraded architecture, this version refines every major cognitive dimension—from nuance detection to multi-step problem solving. A suite of enhanced variants works behind the scenes, each specialized to deliver more accuracy, coherence, and depth. GPT-5.2 Instant is engineered for speed and reliability, offering ultra-fast responses that remain highly aligned with user instructions even in complex contexts. GPT-5.2 Thinking extends the platform’s reasoning capacity, enabling more deliberate, structured, and transparent logic throughout long or sophisticated tasks. Automatic routing ensures users never need to choose a model themselves—the system selects the ideal variant based on the nature of the query. These upgrades make GPT-5.2 more adaptive, more stable, and more capable of handling nuanced, multi-intent prompts. Conversations feel more natural, with improved emotional tone matching, smoother transitions, and higher fidelity to user intent. The model also prioritizes clarity, reducing ambiguity while maintaining conversational warmth. Altogether, GPT-5.2 delivers a more intelligent, humanlike, and contextually aware AI experience for users across all domains.

GPT-5.4 is a frontier artificial intelligence model developed by OpenAI to perform complex reasoning, coding, and knowledge-based tasks. It is designed to support professionals across industries by helping them automate workflows, analyze information, and produce detailed work outputs. The model integrates advanced reasoning capabilities with powerful coding performance derived from earlier Codex systems. GPT-5.4 can generate and edit documents, spreadsheets, presentations, and structured data used in business operations. One of its major improvements is its ability to interact with tools and external systems to complete multi-step workflows across different applications. This capability allows AI agents built on GPT-5.4 to perform tasks such as data entry, research, and automated software interactions. The model also supports extremely large context windows, enabling it to process long documents and maintain awareness across extended tasks. Improved visual understanding allows GPT-5.4 to interpret images, screenshots, and complex documents more effectively. It also introduces better web browsing and research capabilities for locating and synthesizing information online. Compared with previous versions, GPT-5.4 reduces factual errors and produces more consistent responses. Developers can access the model through APIs and integrate it into software applications, automation systems, and enterprise workflows. Overall, GPT-5.4 represents a significant step forward in AI capabilities for knowledge work, software development, and intelligent automation.