ChatGPT Work vs Microsoft 365 Copilot vs Glean: Choosing an Enterprise AI Agent in 2026

On July 9, 2026, OpenAI launched ChatGPT Work, and the enterprise AI question stopped being "which chatbot" and became "which agent." Buyers now weigh three overlapping bets: ChatGPT Work (an agent that ships finished work), Microsoft 365 Copilot (AI embedded in Office and Teams, grounded in your Microsoft tenant), and Glean (enterprise search and agents across every SaaS app you own). They sound similar in a demo. They are architected differently, and the difference decides which one fits your stack. Here is what each does, where the data lives, and how to choose. For the full field, see our enterprise AI agents guide.

What each one actually does

ChatGPT Work is an AI agent that takes action across a user's apps and files, works on complex projects for hours, and turns a goal into completed work: finished sheets, slides, docs, and shareable web apps. It ships a unified plugin directory connecting ChatGPT to Slack, Gmail, Google Drive, calendars, and CRM software. Scheduled Tasks automate recurring work, and the desktop app carries an in-app browser plus Computer Use to act across websites and local apps. It runs on the new GPT-5.6 model family. The pitch is output, not answers: you state an outcome, it produces the artifact.

Microsoft 365 Copilot is AI woven into Word, Excel, PowerPoint, Outlook, and Teams. It drafts in the app you already have open, grounded in your work data through the Microsoft Graph (your email, files, chats, and calendar). On top of chat, Microsoft ships reasoning agents: Researcher combines a deep research model with Copilot orchestration, the Microsoft Graph, connectors, and the web index for complex multi-step research. Analyst runs chain-of-thought data analysis like a data scientist. Copilot Studio lets teams build custom agents with agent flows.

Glean is a Work AI platform built on one permissions-aware Knowledge Graph, exposed through four surfaces: Search, Assistant, Agents, and Apps. It indexes 100+ connected apps (Drive, Slack, Confluence, Jira, Salesforce, ServiceNow, GitHub, and more), pulling content plus each object's source-system permissions. The Assistant answers with citations back to source documents and routes across multiple models depending on task and policy. Glean Agents build, deploy, orchestrate, and govern autonomous agents that take action: open a Jira ticket, update a Salesforce opportunity, post a Slack summary, kick off a GitHub PR.

Where your data lives (the real differentiator)

This is the decision that outlasts any feature list.

Microsoft 365 Copilot keeps everything inside your Microsoft 365 commercial data boundary. Its context is the Graph: it is only as smart as what already sits in your Microsoft tenant. That is a strength if you run on Microsoft, a limit if your knowledge lives in Notion, Confluence, or Google Workspace.

Glean builds its own permissions-aware index across all your SaaS apps and enforces access-control lists at query time, on every retrieval. Nobody sees a document through Glean that they could not open directly. That indexed graph is what makes Glean strong at "find and reason across everything," and it is why deployment takes real integration work.

ChatGPT Work connects live to your apps through the plugin directory and Computer Use rather than pre-indexing them into a persistent graph. It reaches into Slack, Gmail, Drive, and your CRM in the moment, and can drive any website or local app through the browser. That makes it the most flexible reach and the least dependent on a fixed connector catalog, at the cost of the always-warm, org-wide search index Glean maintains.

Comparison table

Agentic ability and governance

All three now "do," not just "answer," but the emphasis differs. ChatGPT Work leans hardest into autonomous execution: long-running tasks that end in a finished artifact, and Computer Use to operate tools that have no API. Glean leans into governed action inside your existing systems of record, with agents that respect the same permissions as search. Copilot leans into in-flow assistance plus Copilot Studio for teams that want to build their own agents on Microsoft's rails.

Governance tracks the same split. ChatGPT Work gives admins centralized control over connected tools, data, and actions, a Compliance API for visibility into conversations and actions, and an auto-review system that checks sensitive actions before they run. Copilot inherits Microsoft Purview, Entra identity, and tenant-level compliance, which is hard to beat if you already run that stack. Glean's model is permissions-aware retrieval plus agent governance with sharing controls and guardrails, purpose-built for compliance-heavy environments.

Pricing reality

Microsoft 365 Copilot is a $30/user/month add-on, but it requires a qualifying base license (E3, E5, or Business Premium). All-in, that is roughly $66 to $87 per user per month on enterprise plans. Glean does not publish list prices: reported base seats run about $50 to $75/user/month with a roughly 100-seat minimum, and advanced AI and agent usage bills through consumption-based credits, so spend scales with usage. ChatGPT Work rides existing ChatGPT plans and is available now for Pro, Enterprise, and Edu, with Plus and Business within days. OpenAI does not publish a public Enterprise list price, so budget on a custom, seat-based quote.

Who should pick which

Pick Microsoft 365 Copilot if you are a Microsoft-centric enterprise. When your knowledge already lives in the Graph and your compliance runs on Purview and Entra, Copilot is the lowest-friction, best-governed choice, and the in-app drafting is genuinely where work happens.

Pick Glean if your knowledge is scattered across many SaaS tools and you need one trustworthy, permission-aware answer across all of them. It is the strongest cross-app search and the safest bet for regulated teams that want agents bounded by real ACLs. Expect a longer rollout and an enterprise contract.

Pick ChatGPT Work if the job is to produce finished deliverables and operate tools directly. When you want an agent that runs for hours and hands back a built spreadsheet, deck, doc, or web app, and can click through any site or local app to get there, it is the most output-oriented of the three. It also travels best across a mixed, non-Microsoft stack.

The honest answer for many large orgs is two of the three: Copilot or Glean as the governed knowledge layer, ChatGPT Work as the execution agent on top. Run a scoped pilot on a real workflow before you commit a seat count. See the enterprise AI agents guide for the wider shortlist.