Best Foundation Models for Microsoft 365

GPT-6 Astra is an advanced general-purpose AI model from OpenAI designed for demanding agentic, technical, scientific, and professional workflows. The model combines reasoning with computer-use capabilities that let it interact with applications, websites, development environments, productivity software, and specialized tools. It can perform activities such as online research, CRM updates, form completion, calendar organization, data analysis, software testing, troubleshooting, and frontend quality assurance. Astra is also trained for professional artifact creation, including documents, presentations, spreadsheets, analyses, websites, applications, and visual designs that follow provided templates and business conventions. Its software engineering capabilities support complex coding, codebase understanding, debugging, database migration, verification, and extended autonomous development tasks. OpenAI has also introduced a Codex context system for Astra that can maintain notes across context windows and search earlier conversation and tool history instead of relying exclusively on repeated summarization. Scientific capabilities span areas such as mathematics, biology, chemistry, health, data analysis, and the use of specialized research software. The model includes strengthened alignment and cybersecurity safeguards intended to help it remain within authorized task boundaries while supporting legitimate activities such as secure code review and vulnerability remediation. GPT-6 Astra is available across supported ChatGPT plans and developer platforms, including the OpenAI API and Amazon Web Services infrastructure.

GPT-6 Sol is a frontier AI model from OpenAI built for professional knowledge work, software development, business automation, computer use, and agentic applications. It brings many of the advances introduced with GPT-6 Astra to a model optimized for greater cost efficiency and higher-volume use. GPT-6 Sol can apply configurable reasoning effort to complex tasks, giving developers and users control over how much computation is used for different workloads. Its coding capabilities support long-horizon software engineering, codebase modification, debugging, testing, and agent-driven development in tools such as Codex. For professional workflows, the model can work across applications and tools to complete multi-step tasks in areas such as sales, marketing, operations, finance, support, and HR. OpenAI also reports improved factuality compared with GPT-5.6 Sol, reducing errors on its internal evaluation of difficult real-world conversations. Computer-use capabilities allow Sol-powered agents to navigate software interfaces and perform extended workflows that require multiple actions and decisions. Enhanced prompt caching provides higher cache-hit rates and discounts on reused input context, making the model better suited to persistent agents and long conversations. GPT-6 Sol is available to developers through the OpenAI API as gpt-6-sol and is also offered in ChatGPT Work and Codex.

GPT-6 Luna is a lightweight, cost-efficient model in OpenAI’s GPT-6 family built for coding, professional tasks, computer use, and high-volume AI applications. The model incorporates advances from the same generation as GPT-6 Astra while emphasizing lower inference costs and greater efficiency for everyday workloads. API pricing is $0.10 per million input tokens and $0.50 per million output tokens, making Luna suitable for applications that process large volumes of requests. In professional work, GPT-6 Luna can execute multi-step workflows involving business applications, tools, and structured tasks across functions such as sales, marketing, operations, support, finance, and HR. For software engineering, the model can work on real codebases, perform extended development tasks, and operate within coding agents such as Codex. Its computer-use capabilities allow AI agents to interact with software interfaces and carry out longer workflows that require repeated actions and decisions. OpenAI also reports substantial factuality improvements over GPT-5.6 Luna, with higher reasoning settings enabling stronger performance on difficult factual questions. GPT-6 prompt caching provides higher cache-hit rates and discounted cached input, helping persistent agents and long conversations reuse context more efficiently. GPT-6 Luna is available through ChatGPT Work, Codex, the OpenAI API, and the ChatGPT desktop app for eligible users.

GPT-5.6 Luna is OpenAI’s fast, cost-efficient model in the GPT-5.6 lineup. The GPT-5.6 family includes Sol for flagship performance, Terra for balanced everyday work, and Luna for strong capability at the lowest listed price. Luna is designed for users who need scalable AI support for routine tasks, coding assistance, workflow automation, analysis, and production API use cases where speed and cost matter. According to the pasted preview text, Luna is priced below both Sol and Terra, making it the most affordable GPT-5.6 option for high-volume workloads. The model is included in GPT-5.6 benchmark previews across Terminal-Bench 2.1, GeneBench v1, ExploitBench, and ExploitGym, showing that it is part of the same technical family used for coding, biology, and cybersecurity evaluations. Luna benefits from safeguards developed across the GPT-5.6 series, including model-level refusal training, real-time cyber and biology misuse classifiers, account-level signals, differentiated access, monitoring, enforcement, and ongoing testing. These controls are designed to preserve legitimate use cases such as debugging, code review, defensive testing, security education, and productivity automation while constraining prohibited misuse. GPT-5.6 Luna is planned for broader access through ChatGPT, Codex, and the API after the limited preview period. GPT-5.6 Luna helps developers and organizations run useful AI workflows with a practical balance of affordability, responsiveness, and safety.

GPT-5.6 Terra is OpenAI’s balanced GPT-5.6 model for users who need strong performance across everyday work, development tasks, enterprise workflows, and technical analysis. The model is part of the GPT-5.6 family alongside Sol and Luna, with Terra positioned as the middle tier for capable, cost-efficient use. Terra is described as having competitive performance to GPT-5.5 while being 2x cheaper, making it useful for teams that want advanced capability without always using the flagship model. It supports coding workflows, agentic tasks, cybersecurity-related defensive work, biology workflows, knowledge work, and tool-assisted automation. In benchmark previews, Terra appears alongside Sol and Luna in evaluations for coding, biology, ExploitBench, and ExploitGym. The model benefits from the GPT-5.6 safeguard stack, which includes model-level refusals for prohibited cyber assistance, real-time cyber and biology misuse classifiers, and account-level risk review. These safeguards are designed to preserve access to legitimate work such as code review, debugging, vulnerability research, patch development, security education, and defensive testing. GPT-5.6 Terra is planned for availability through the API, Codex, and broader OpenAI products after the limited preview period. GPT-5.6 Terra helps teams get a balanced model for high-quality AI work when they need strong reasoning and automation at a lower cost than Sol.

GPT-5.5 is a next-generation AI system built for execution-heavy workflows across coding, research, business analysis, and scientific tasks. It can interpret complex instructions, break them into actionable steps, and carry them through to completion while interacting with tools and systems. The model supports creating applications, generating reports, analyzing datasets, and navigating software environments seamlessly. It also integrates with workspace agents—custom AI agents that automate recurring and multi-step processes across teams. These agents can handle tasks such as lead research, reporting, and workflow automation, either on demand or on schedules. GPT-5.5 enhances productivity by reducing manual effort and enabling continuous task execution across tools. With enterprise-grade safeguards and monitoring, it ensures secure and controlled automation. It is well-suited for organizations looking to scale operations and improve efficiency through AI-driven workflows.

Claude is an advanced AI assistant created by Anthropic to help users think, create, and work more efficiently. It is built to handle tasks such as content creation, document editing, coding, data analysis, and research with a strong focus on safety and accuracy. Claude enables users to collaborate with AI in real time, making it easy to draft websites, generate code, and refine ideas through conversation. The platform supports uploads of text, images, and files, allowing users to analyze and visualize information directly within chat. Claude includes powerful tools like Artifacts, which help organize and iterate on creative and technical projects. Users can access Claude on the web as well as on mobile devices for seamless productivity. Built-in web search allows Claude to surface relevant information when needed. Different plans offer varying levels of usage, model access, and advanced research features. Claude is designed to support both individual users and teams at scale. Anthropic’s commitment to responsible AI ensures Claude is secure, reliable, and aligned with real-world needs.

Grok is a powerful AI chatbot developed by xAI, designed to deliver real-time, intelligent, and conversational assistance. It is uniquely integrated with the X platform, enabling access to live data and trending topics for more relevant responses. Grok is built to handle a wide range of tasks, including answering questions, generating content, and assisting with research. The platform combines advanced reasoning capabilities with a conversational tone, often incorporating humor and personality. It uses large-scale language models to understand context and provide accurate, meaningful answers. Grok is particularly useful for staying updated on current events and social trends. Its real-time data access sets it apart from traditional AI assistants that rely on static knowledge. The platform is designed for both casual users and professionals seeking quick insights. It continuously evolves with updates and improvements from xAI. Overall, Grok delivers a modern AI experience focused on relevance, engagement, and real-time intelligence.

GPT-5.5 Pro is a next-generation AI model built for execution-heavy tasks across coding, research, business analysis, and scientific workflows. It can interpret complex instructions, break them into steps, and carry work through to completion using tools and automation. The model supports tasks such as generating documents, building applications, analyzing datasets, and navigating software environments. It is designed to operate across tools, enabling seamless workflows from idea to output. In addition, GPT-5.5 Pro integrates with workspace agents—customizable AI agents that automate recurring and multi-step processes across teams. These agents can handle tasks like lead research, reporting, and workflow automation, running independently or on schedules. Built with enterprise-grade safeguards, the model ensures secure and controlled automation. It helps organizations improve productivity by reducing manual effort and accelerating decision-making. GPT-5.5 Pro is ideal for teams looking to scale operations and handle complex workloads efficiently.