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[This article is prerelease documentation and is subject to change.]
By default, an agent flow initiated by an agent or app fails if it takes longer than two minutes to respond to the calling agent or app. This failure affects the functionality and usability of the agent or app that calls the flow.
Important
This article contains Microsoft Copilot Studio preview documentation and is subject to change.
Preview features aren't meant for production use and may have restricted functionality. These features are available before an official release so that you can get early access and provide feedback.
If you're building a production-ready agent, see Microsoft Copilot Studio Overview.
With express mode, a flow can achieve faster execution times. This feature increases the likelihood that agent flows can complete within the two-minute window, and provide a response in time.
The following image shows an example of the speedup for a specific flow with express mode and without it.
Note
The speedup varies based on the complexity of the flow and the actions used within it. Express mode works best for flows that don't move lots of data from connectors, but take lots of processing time. We recommend testing your flows to see if express mode is suitable for your specific scenario and how much it improves flow performance. If you encounter a flow runtime error mentioning a data limitation, we suggest that you turn off express mode, and try it with other flows instead.
Prerequisites
To use express mode, your flow must meet the following requirements:
- The flow must have either the When an agent calls a flow or the When an app calls a flow trigger.
- The flow must have a Response action, either Respond to agent or Respond to app.
- The flow must have a Copilot Studio plan associated with it.
- The Power Automate environment must be on new infrastructure. See Availability for more information.
Turn on express mode
Select Flows and then select the flow for which you want to turn on express mode.
In the Details section of the Overview page, select Edit.
The Details panel appears.
Turn on Express mode. The toggle is at the bottom of the panel.
Note
You can also turn on express mode from the When an agent calls a flow or the When an app calls a flow trigger itself while you're building the flow in the designer on the trigger card.
Guidelines for using express mode
| When to use express mode | When not to use express mode |
|---|---|
| Logic heavy flows: Your agent flow doesn't return large amounts data from connectors response (Large data amounts exceed the memory limit of express mode). | Data heavy flows: Your agent flow moves lots of data (for example, list the rows in a large table, or a get items action returns 1,500 rows of data with 100 columns). |
| Your agent flow has a response action, meaning the flow is time sensitive. An agent waits for the flow to execute and send back a response as quickly as possible. | Your agent flow doesn't have a response action. The flow is a fire-and-forget type. It doesn't need to send back a response to a calling agent or app. |
| Express mode runs successfully and optimally during test. | Express mode fails during test due to a variable size limit or memory limit. If the flow fails during a test, you'll likely hit these issues when the flow is deployed and run in production. |
Availability
Express mode is currently only available for some environments that are upgraded to a new architecture that supports it. Microsoft is in the process of upgrading environments to support express mode. No action is required on your part to upgrade your environment.
To check if express mode is available in your environment:
Make sure you have a simple agent flow in Copilot Studio with either the When an agent calls a flow or When an app calls a flow trigger, and some action. If you don't have a flow with these elements, create one.
Check for the express mode toggle in the designer on the trigger card.
If express mode doesn't appear, your environment doesn't support this feature yet.
Note
If your environment isn't on the new infrastructure yet, your environment might have some flows that are delaying the environment upgrade. You might follow some steps outlined in Power Automate environments move to new architecture to help unblock the automatic future upgrade.
Licensing
Express mode is only available for flows under Copilot Studio plan. There's no added cost to running your flows in this mode. You're still billed for the number of actions used under Copilot Studio metering.
Limitations
Here are some known limitations to be aware of when using express mode.
Limitations at flow publish
Delay and webhook actions in the flow aren't supported when express mode is turned on. Errors appear when saving the flow. For such cases, try turning off express mode and try again.
Limitations at flow runtime
There are some runtime limitations when using express mode.
Execution time
With express mode turned on, flows must complete in two minutes. Flows that take longer time out.
Flow size
- You shouldn't include more than 100 actions in a flow run. The actions count includes loops, which count as one action for each loop iteration. The following limits apply for loops:
- Apply to each loop on an array: max 100 items
- Do until loop: max 100 iterations
- Variable content limit: 1,024 characters. If you can, find workarounds to not insert more than 1,024 characters into variables such as Set variable or Append to String Variable or Initialize variable.
100 actions is a safe limit for flow size. You might be able to get in more than 100 actions, depending on how heavy the flow is, and on how much data processing the flow does. For more information on managing flow size, see Guidelines for using express mode.
Message size
The message size limit for data passed in an individual action (connector response) is 64 KB.
Error messaging
We show error messaging at runtime detailing why the flow failed if it's due to any of the previously mentioned runtime limitations. If you have a flow that doesn't meet the prerequisites for express mode, we recommend running the flow with express mode Off.
Other limitations when using express mode
- Testing your flow automatically doesn't work in the flow designer. Testing automatically uses flow resubmit, and flow resubmit can't be used with agent-triggered or app-triggered flows.
- Loop iterations don't appear in the Run details view when a connector response exceeds the memory limit. In some cases, you might notice that loop iterations don't show up when you monitor a loop (Apply to each or Do until). Test your flow in a development environment, and then turn on express mode for debugging before you publish to production.