In March 2026, someone filed a feature request on GitHub Community that I have thought about more than any product announcement from that month. The setup is two repositories. A web app and an orders-service it consumes. The web app calls the service's endpoints, depends on its DTOs, and has to stay aligned with every route rename, payload change, and validation rule. The request walks through what Copilot cannot do across that boundary: it cannot reason about contracts defined in the other repo, cannot detect when the frontend calls an endpoint that no longer exists, cannot coordinate one change across both sides. It ends with two questions. Is this on the roadmap, and are there recommended best practices to approximate this behaviour today?
GitHub has not answered. I eventually left a reply in the thread myself, because the second question deserved one, and this post is the long version of that reply.
The honest answer is more useful than "wait for the roadmap". As of June 2026 there are three working ways to give GitHub Copilot context across repositories. All three are real, all three ship today, and all three have a ceiling that is worth knowing about before you invest in one. Underneath all three sits the same unanswered question, and that question is the part I actually want to get to.
