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Copilot Studio Agent resetting when processing PDF drawings (300MB+) via Claude 4.6 Sonnet
Hello everyone,
I am building an automated drawing review verification agent inside Copilot Studio using the Claude 4.6 Sonnet model. The goal of the agent is to read a comments package (20-40MB) and verify if those design comments were successfully incorporated into a milestone drawing set (300MB–400MB).
When testing this workflow natively within Claude, the model handles the token load perfectly and returns an accurate compliance/incorporation summary within approximately 20 minutes.
However, when running the exact same agent setup within Copilot Studio, the conversational canvas repeatedly crashes and resets the session. I suspect I am hitting the 100-second synchronous conversational timeout or overloading the chat runtime payload limits due to the massive file sizes.
Because of corporate compliance policies, this agent must live within our Microsoft tenant so it can be scaled across our operations team via Microsoft 365.
How can I fix Copilot Studio to have its performance match Claude's, as it is utilizing the same agent model.
I am fairly new to working with AI but am willing explore any avenue as if I can figure out a solution this will help save a lot of time for colleagues.
Thanks in advance for any insights!
2 Replies
First thing to understand: the model is not the problem. Claude is handling the workload just fine. What is crashing is the Copilot Studio conversational runtime, which has a hard synchronous timeout of around 100 seconds per turn and strict payload size limits. A 20-minute analysis on hundreds of megabytes of files will hit that wall every time, regardless of which model you use underneath.
You cannot fix this by tweaking settings. The architecture needs to change.
I suggest you to stop passing the documents through the chat canvas. Instead, store your drawing files in SharePoint, have users reference them by link, and let Copilot Studio do only one thing: receive the request, confirm it, and kick off a Power Automate flow in the background. That flow does the actual analysis, calls the model, and when it finishes, posts the results back via Teams message or email.
The good news is that Microsoft now supports async responses for agent flows natively, meaning the flow can run well beyond the old limits and still return the result to the conversation once it is done. In your Power Automate flow, open the "Respond to the agent" action, go to Settings, and turn on Async response.
Doc: https://learn.microsoft.com/microsoft-copilot-studio/flow-asynchronous-response
Thank you so much! I will go down this path and see what I can find out.
