ChatGPT Work vs Microsoft Copilot, and the open-source layer you can own

An agent and an assistant, defined

ChatGPT Work is OpenAI's agent inside ChatGPT. It takes a goal, works across connected apps and files, and returns finished material such as sheets, slides, docs and sites. Microsoft Copilot is Microsoft's assistant across Microsoft 365: it is built into Word, Excel, PowerPoint, Outlook and Teams, grounded in your work by Work IQ, and able to draw on the models Microsoft offers. Both are closed products sold with a subscription.

Where each one keeps your work

Neither product offers a self-hosted install. ChatGPT Work runs in OpenAI's cloud on OpenAI's models, and its agents, plugins and scheduled tasks live inside the ChatGPT product. Microsoft Copilot runs in Microsoft's cloud, keeps your agents in Agent Builder and Copilot Studio, and selects a model per request from the set Microsoft curates.

For a team already inside Microsoft 365, Copilot is the shortest path to an assistant in the apps you use. That still leaves the agent layer, the shared memory and the connectors that carry work across tools.

The open-source layer a team can own

Kortix is the open-source AI Operating System: your agents, their skills, your company memory, and every connector in one git repo you own, with the agents working on real cloud computers. The difference from both closed products is where the configuration lives: in files your team owns and can review.

A project is a git repo with kortix.yaml at its root. The top of a v2 manifest, from the Kortix manifest reference:

kortix_version: 2default_agent: kortixagents:  kortix:    file: agents/kortix.md    connectors: all    secrets: all

Run it on Kortix Cloud, in your VPC, or on your own on-prem network. Self-host is free. 3,000+ apps in a click, plus MCP, OpenAPI, Postman, GraphQL and raw HTTP. Connector credentials are brokered server-side and never enter the machine. Session work reaches main through a change request. Merge is default-deny for agents.

A rule for picking

• Pick Microsoft Copilot when the team works inside Word, Excel, Outlook and Teams and wants an assistant grounded in Microsoft 365 data. Governance and permissions lists what to ask of any platform.
• Pick ChatGPT Work when the work starts from ChatGPT context and ends as a deck, a sheet or a site.
• Pick Kortix when you want the agents, skills, memory and connectors in a repo you control, on any model, self-hosted or managed. ChatGPT Work vs Kortix compares those two directly.

The Kortix blog maps the open-source Microsoft Copilot alternatives by product.