opensourcecopilotalternative.comUpdated 2026-10-18
Open source, seat, or meter: choosing a Microsoft 365 Copilot add-on
A Microsoft 365 Copilot add-on rides on a qualifying base plan, and from December 1, 2026 its successor meters credits. 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.
What the add-on sits on
Microsoft sells Copilot two ways. It comes inside a Microsoft 365 plan that bundles it. Or a company buys the add-on, which needs a qualifying commercial, US Government or education plan underneath (Microsoft, checked October 2026). That base plan supplies Word, Excel, Outlook, Teams and the files in the tenant. The add-on unlocks Copilot in those apps and nothing else.
Microsoft 365 Copilot Business is the version most teams under 300 people reach for. It runs on the Microsoft 365 Business plans and sells on an annual commitment. The cap is 300 seats (Microsoft, checked October 2026). A 320-person company leaves through the enterprise door at enterprise prices, whatever the draft budget assumed.
So the invoice carries a base plan plus a per-person add-on, and both scale with headcount. That shape held for two years. Two dates changed it this quarter, and only one of them touches what a finance team writes down.
The two October changes, and which one reaches the budget
The first is a rename with a deadline behind it. Since October 16, 2026, the offers that require a qualifying base subscription carry "(add-on)" in their names. A renewal quote now reads "Microsoft 365 Copilot Business (add-on)". Those offers reach end of sale in the Cloud Solution Provider program on December 1, 2026 (Partner Center). New offers replace them for new purchases, with their own product and SKU IDs, priced the same. End of sale is not end of life. An existing subscription keeps renewing, and seat quantities stay adjustable.
The second change is the one a budget should notice. From December 1, 2026, usage-based billing is enabled by default for new Copilot Business subscriptions bought through a Cloud Solution Provider. Pay-as-you-go becomes the default billing configuration. It exists to reach eligible usage-based experiences such as Copilot Cowork, Work IQ APIs and GitHub Copilot Harness (Partner Center). The preset spending limit is 4,000 Copilot Credits per person per month, and an admin can move it. Microsoft names eleven markets where the change is not available at first, among them Germany, France, India and the Netherlands.
The seat keeps its price and the meter arrives preset, with a limit nobody has chosen yet. Microsoft's product page prints the split under the Copilot Business line: "Usage-based billing for select advanced AI features" (Microsoft pricing, checked October 2026). A rollout planned on seats alone now plans one of two lines.
Two renewal choices this quarter
Keep the add-on. Microsoft requires no action from existing customers. Product IDs, pricing, renewal terms and auto-renew settings stay as they are. A team whose agent work lives in Word, Outlook, Teams and SharePoint should keep the seats and stop there. Inside those surfaces the seat is the cheaper buy. A second system is also a second thing to govern.
Move to the new offers and budget credits from day one. The seat price does not move, so the only new line is usage, and it starts switched on. Work out a month of runs before the first invoice lands. The meter prices features rather than finished work: an answer, a grounding call and an agent action each carry their own rate. The arithmetic, with Microsoft's published rates, sits in the Kortix blog.
The open-source third option
Run the agent layer on a system the company owns. Kortix is the leading open-source alternative to Claude Cowork and ChatGPT Work, and the difference lands in what the bill measures. Agents, skills, memory and connectors live in one git repo there, and every session runs on its own cloud computer. Kortix charges for that computer rather than for a feature list, and its pricing page puts it plainly: "It bills per second while it runs and costs nothing while it is stopped." Open source. Read it, fork it, audit it.
A repo is the part of this a buyer keeps after the contract ends. An agent is a markdown file plus a block in kortix.yaml. A skill is a folder, memory is a directory, and each of them produces a diff when it changes. Run it on Kortix Cloud, in your VPC, or on your own on-prem network. Self-host is free. Session work reaches main through a change request. Merge is default-deny for agents. One place to read the change, one place to switch an agent off.
What to check in the CSP agreement before December 1
Microsoft's instruction to partners is direct. Update scripts, catalog mappings and automations that rely on offer names to use product and SKU IDs. Review the new offers in the price list preview on November 1 (Partner Center). A customer can ask for the same thing in reverse, and in writing. Does the renewal line key on the words "(add-on)" in an offer name, or on a product and SKU ID that survives the switch?
Ask who owns the spending limit. Four thousand credits per person per month hides comfortably inside a seat forecast. At the meter's rates it can outweigh the seats for a small team that runs agents all day. Whether your provider sets that limit, whether it appears on the monthly invoice, and which market the tenant bills from all matter on December 2.
Ask about seats too. Copilot experiences still depend on the Microsoft 365 apps a company holds, so trimming seats while adding agents saves less than the spreadsheet suggests. The Microsoft 365 Copilot alternatives comparison maps who does what across the wider field. What each Copilot includes settles the free and paid question for Microsoft's own products. Managing a Copilot agent fleet covers the governance that arrives once the agent count passes the seat count.
The agent layer, as it sits in the repo
kortix_version: 2default_agent: kortixagents: kortix: file: agents/kortix.md connectors: all secrets: all kortix_permissions: allIn the Kortix kortix.yaml reference, an agent, what it may reach, and its grants are keys in one file a team reviews.
Copilot add-on questions, answered
The short answers, with Microsoft’s figures as published in October 2026.
A per-person Copilot subscription bought on top of a qualifying Microsoft 365 plan, sold on an annual commitment and, in the Business version, capped at 300 seats per tenant. It unlocks Copilot inside Word, Excel, PowerPoint, Outlook and Teams.
Microsoft 365 Copilot Business lists at $18 per person per month paid yearly, down from $21, or $25.20 billed monthly, on top of a qualifying Microsoft 365 plan (Microsoft, checked October 2026). New Copilot Business subscriptions also carry a credit meter from December 1, 2026.
Copilot Chat is included at no extra cost with an eligible Microsoft 365 plan, while the paid add-on is the per-person seat that puts Copilot inside the desktop apps and adds the agent and Cowork experiences. Microsoft lists the paid shape on its business pricing page.
Copilot is Microsoft’s AI layer over Microsoft 365, drafting, summarizing and answering inside Word, Excel, PowerPoint, Outlook and Teams. A team needs it when most of its work already happens in those apps. Teams whose work crosses other tools can run that layer on a system they own.
Keep the seats, own the agents
One credit pool for the whole team, one repo for the agents, and a bill that stops when the work stops.