With new agent mode for Excel and Word, Microsoft touts “vibe working” (arstechnica.com)

Microsoft announced two new AI document-generation features for Microsoft 365 that aim to let knowledge workers create complex Word, Excel and PowerPoint assets from simple text prompts. The first, Agent Mode (powered by OpenAI’s GPT-5), is integrated into web versions of Word and Excel and acts like a multi-step agent: it plans sequences of work, executes steps and runs a validation loop to reduce errors. Microsoft plans to bring Agent Mode to native desktop apps later. The second, Office Agent for Copilot, uses Anthropic models inside Microsoft’s Copilot chatbot to generate Word and PowerPoint files; it doesn’t attempt the same full planning-and-validation routine but is billed as a more reliable replacement for earlier Copilot document generation and is available initially through the Frontier Program for Microsoft 365 subscribers. The move matters because it signals a shift from single-shot LLM completions toward agentic workflows that can iterate, validate and manage multi-step tasks—improving quality for high-stakes document and spreadsheet creation. It also highlights Microsoft’s multi-model approach (OpenAI + Anthropic) and a staged rollout that could change how teams “vibe work” — i.e., iterate on documents entirely via chat prompts. Key implications include faster knowledge-worker workflows, potential reductions in hallucinations via validation loops, and new product fragmentation/confusion because of similar naming between differently powered features.