Built a Copilot Studio agent that collects missing data in a loop, calls an external shipping API via HTTP, and returns real delivery prices — sharing the full flow
Most Copilot Studio agents only use Microsoft tools — query Excel, read SharePoint, send an email. The moment you need to call an external third-party system via HTTP, most setups fall apart fast.
So I built a logistics assistant that shows exactly how to do it — including the messiest part: the user never gives you all the data upfront.
Here's what it actually does:
- Takes an incomplete request — "get me a delivery price from Chicago to New York" — and figures out what's missing before making any API call
- Runs a decision loop driven by a single prompt action that decides the next step every iteration: ask the user, search the web, call the API, answer, or stop
- Searches the web automatically for missing details — if the user says "it's just a shoebox," the agent finds the dimensions itself instead of asking
- Builds a structured JSON payload and sends it via HTTP request to an external shipping API with proper auth headers
- Returns real carrier options with prices and delivery times
The architecture is one topic acting as a controller, one prompt making every routing decision, one variable accumulating everything — original request, follow-up answers, web results — so the agent gets smarter with every loop.
The main point of this build is the HTTP pattern: once you can call one external API this way, you can call any of them. The logistics use case is the demo — the same architecture applies to any third-party system your business connects to.
Three live demos in the video showing the full loop from vague input to real API response.
The full flow is in my flospect library — same link as always, this build has been added. Every node, prompt, variable, and HTTP setup. Ready to view and rebuild in your own environment.
Video walkthrough + library link in the comments.
What external APIs or third-party systems have you needed to connect to from Copilot Studio? Curious what others are trying to integrate.