Author: @atilayberber
Copilot can now get your semantic model documentation started for you, both for individual measures and for the model as a whole. The model owner still has the final word, though. What Copilot writes is a draft, not a sign-off.
Why it matters now
An undocumented model, especially one inherited from someone who left the team, means hours of reading DAX. And it’s not only people who need those descriptions anymore. Copilot, Fabric data agents and Fabric IQ in Microsoft 365 Copilot all lean on model metadata when they answer questions. Clearer descriptions lead to more trustworthy AI answers.
Two separate features
| Feature | What it writes | Where you use it |
|---|---|---|
| Measure descriptions (Copilot) | A description of one measure, based on its DAX | Model view in Power BI Desktop or the service |
| Semantic model Auto-Description (preview) | An overview of the model from its metadata and structure | The model details page in the OneLake catalog |
Step by step: a measure description
- In Model view, select the measure and click the Copilot button next to the description field.
- Read the result. Choose “Keep it”, “Try again” or “Discard”.
- Edit it into your own business language where needed (rules like “excludes returns, includes VAT”).
Two requirements to keep in mind: the workspace must be on a Fabric capacity, and the measure has to be valid, with no errors.
Where human review comes in
Copilot can explain what a formula does. It can’t know why the measure exists. A weak model also produces weak descriptions. Here’s my checklist:
- Business definition: What does “net sales” cover at your company? Only you know that.
- Unit and period: Currency or units? YTD? Put it in the description.
- Consistency: Similar measures should follow the same pattern.
- Red flags: Auto-Description can surface issues such as duplicate tables or weak relationships. Fix those in the model before polishing the text.
A documentation routine that sticks
- No new measure ships without a description. Ask about it in code review.
- Copilot writes the first draft, the model owner approves. Make it a two-step rule.
- Once a month, list the measures with empty descriptions (for example with INFO functions in DAX query view).
Bottom line: Copilot speeds up the most tedious part of documentation. The discipline is still the team’s job.
Sources
- Measure descriptions with Copilot – Microsoft Learn
- Generate measure descriptions with Copilot (preview) – Power BI Blog
- What’s new in Microsoft Fabric – Microsoft Learn
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