Copilot: Missing time period — should it ask or clarify?

[LenaKey]

Hi, 

I’m trying to understand how Copilot handles queries where the user does not provide any date range or time period.
Currently, it seems that Copilot proceeds with a calculation without clarifying which time period it assumed.

Is this expected behavior?
Is there a recommended way to make Copilot either:

         1. ask the user for the missing time period, or

         2. clearly state in its response what time period it used?

Any guidance or best practices would be appreciated.

[v-kpoloju-msft]

Hi @LenaKey,

Thank you for reaching out to the Microsoft Fabric Community Forum. Also, thanks to @Kedar_Pande,  for his inputs on this thread.

What you are seeing is expected behaviour. If a user asks Copilot for a metric without specifying a date range, Copilot will often assume one based on the model and current filters. This can make the result unclear if the time period isn’t visible to the user.

To improve this, you can guide Copilot to either ask for the date range or clearly state the period it used by adding AI Instructions to your semantic model:

In Power BI Desktop, open your model. Select Home > Prep data for AI. Go to Add AI instructions. Add guidance like: “If a question involves time and no period is specified, ask the user to confirm (e.g., last month, YTD, all data), and always state the time period used in the answer.”

Refer this link: https://learn.microsoft.com/en-us/power-bi/create-reports/copilot-prepare-data-ai-instructions 

This helps ensure Copilot delivers clearer and more consistent responses when a date range isn’t provided.

Hope this clears it up. Let us know if you have any doubts regarding this. We will be happy to help.

Thank you for using the Microsoft Fabric Community Forum.

[v-kpoloju-msft]

Hi @LenaKey,

Just checking in to see if the issue has been resolved on your end. If the earlier suggestions helped, that’s great to hear! And if you’re still facing challenges, feel free to share more details happy to assist further.

Thank you.

[v-kpoloju-msft]

Hi @LenaKey,

Just wanted to follow up. If the shared guidance worked for you, that’s wonderful hopefully it also helps others looking for similar answers. If there’s anything else you'd like to explore or clarify, don’t hesitate to reach out.

Thank you.

[LenaKey]

Thank you for the clarification. Even though I have added AI Instructions guiding Copilot to ask the user for clarification when no time period is specified, this does not seem to work consistently.

In practice, Copilot often defaults to the date range used on the visual or page, or sometimes to a general period from the report. Only occasionally does it actually ask the user to specify the time period.

Is there any way to enforce this behavior so that Copilot always asks for confirmation when the user does not explicitly specify a clear date range? Or is this a current limitation of Copilot’s behavior?

Thank you in advance for your guidance.

[v-kpoloju-msft · Accepted solution]

Hi @LenaKey,
Thank you for the follow-up question.

What you are seeing is expected behaviour. Even when AI Instructions tell Copilot to ask for a missing time, Copilot may still rely on the page filters, visual context, or its own interpretation of the question. This happens because AI Instructions strongly influence Copilot’s behaviour but do not guarantee that it will always ask for clarification. So, the inconsistency you are noticing is not due to anything you configured incorrectly.

At this time, there is no supported way to enforce a rule that Copilot must always ask for a date range whenever the user does not specify one. This is a current limitation of the Copilot experience in Power BI/Fabric. You can improve overall consistency by keeping AI Instructions simple, refining the AI data schema, and using Verified Answers for key business questions, but Copilot will still not behave with 100% determinism when handling missing time periods.

Hope that help. Let us know if you have any doubts regarding this. We will be happy to help.

Thank you for using the Microsoft Fabric Community Forum.

[Kedar_Pande]

@LenaKey 

Always state period upfront in your prompt

Configure semantic model with clear date hierarchies

Response always includes assumed period: "Using data from [date range]"

If this answer helped, please click Kudos or Accept as Solution.
-Kedar
LinkedIn: https://www.linkedin.com/in/kedar-pande

[LenaKey]

@Kedar_Pande thanks,
I’d like to know how to handle a situation where the user does not specify a date range when entering a query. Is it possible for Copilot to ask the user to provide the desired time period?