Copilot in Excel
Copilot skills in Excel: teach it your repeatable processes
The short answer: a Copilot skill is a set of instructions you write once — as a plain text file called SKILL.md saved in your OneDrive — that teaches Copilot how to do one of your repeatable jobs the same way every time. Monthly reporting refresh, variance analysis, a standard dashboard build: instead of re-explaining the process every month, the skill guides Copilot through the steps, the structure, and the formatting.
Why skills exist
Before skills, every Copilot session started from zero. You'd describe the same monthly process, correct the same formatting mistakes, and re-explain the same business logic — every single month. A skill captures the process once: the steps in order, the right structure, the formatting rules, the things to double-check. Copilot follows the skill instead of improvising, which makes the output easier to review, reuse, and trust.
The pre-built skill library
Microsoft ships a library of ready-made skills, finance-flavored at launch — things like building a discounted cash flow, preparing a variance analysis, or refreshing a monthly reporting model. Microsoft's partners (finance software vendors) are building their own skills too. If your job matches one of the pre-built skills, start there before writing your own.
How to write your own skill
A skill is a markdown file named SKILL.md, saved in your OneDrive where Copilot can access it. In plain terms, it contains:
- A name and description — what this skill does, in one or two sentences, so Copilot knows when to reach for it.
- The steps in order — the process as you'd explain it to a new hire. Be specific: which sheets, which columns, which calculations.
- Formatting rules — how the output should look. Number formats, table styles, where the summary goes.
- Checks and gotchas — the things that go wrong. "Verify totals tie to the source tab before finishing" is worth more than ten formatting rules.
Write it the way you'd write a runbook for a colleague. If a new hire couldn't follow it, Copilot can't either.
Plan mode: approve before it acts
Skills arrived alongside a plan mode that addresses the scariest part of agentic Excel: Copilot changing your data. In plan mode, Copilot drafts the list of actions it intends to take — which formulas it will change, which ranges it will touch — and asks you to approve, edit, or answer clarifying questions before it does anything. For financial data, use plan mode until you trust the skill.
Feature availability varies by license, update channel, and region. Details reflect Microsoft's announcements through September 2026. Not affiliated with Microsoft.