About The Manifest

The Manifest is a blog about building on Microsoft 365 Copilot. Practical, opinionated, code-heavy content about the extensibility platform with a deep focus on declarative agents.

Why This Blog Exists

The Microsoft 365 Copilot extensibility landscape is moving fast. New capabilities ship every month (and it keeps me very busy!). Developers and IT pros want to extend Copilot but don't always know where to start, or which patterns actually hold up in production. The Manifest bridges that gap with real scenarios, real code, and honest opinions about what works and what doesn't.

What You'll Find

• Best practices - Patterns that hold up in production, with honest takes on what works and what does not
• Practical examples - Real scenarios with real code you can copy and be productive right away
• Demystifying the agent stack - Breaking down the declarative agent platform so it feels approachable, not overwhelming
• Enterprise context - Connecting your agents to your real organizational data so they reason over what matters
• Real business data - Extending agents to call your APIs, trigger workflows, and interact with the systems your teams already use

About the Author

Sebastien Levert is a Principal Product Manager at Microsoft building the Microsoft 365 Copilot developer experience. This blog is his way of sharing everything he's learned: the wins, the gotchas, and the patterns that actually hold up when real users start asking real questions.