Credit: Microsoft

Microsoft has released TypeSpec for Microsoft 365 Copilot as a fully supported, production-ready offering. This marks the first stable version of the domain-specific language built to simplify how developers create and extend Copilot through declarative agents and API plugins.

A more productive, developer-first workflow

Developers building Copilot extensions have long faced challenges managing complex manifest files and schema definitions. TypeSpec solves this with a strongly typed, fully tooled development experience. Type errors surface at compile time, not at runtime, and integrations with Visual Studio Code and Visual Studio provide IntelliSense, inline documentation, and development-time validation. The result is less time debugging fragile JSON files and more time delivering functionality.

What TypeSpec brings to Microsoft 365 Copilot

TypeSpec is Microsoft’s API-first DSL for modeling services in a clean, human-readable way. The Copilot variant includes Microsoft 365–specific decorators and capabilities so developers can define agent instructions, behaviors, and APIs in one place. The compiler then automatically produces OpenAPI specs, manifests, and configurations that conform to the latest schema requirements.

This approach removes manual editing of multiple JSON or YAML files and replaces it with a concise, familiar syntax designed for scale and reliability.

Simplified agent and plugin authoring

Using TypeSpec with the Microsoft 365 Agents Toolkit, developers can quickly build declarative agents with capabilities like Code Interpreter and Web Search, or connect external APIs with clear service definitions. The GitHub project manager sample illustrates how TypeSpec brings together instructions, actions, and routes without the fragility of hand-built manifests.

Positive feedback from early adopters

Developers in the preview program praised the productivity gains. Microsoft MVP Andrew Connell noted: “TypeSpec brings IntelliSense, type checking, and reusability that developers really appreciate… for developers specifically, my preference and recommendation is definitely TypeSpec.”

Why it matters

General availability means TypeSpec for Microsoft 365 Copilot is now stable, supported and ready for production. Teams building custom agents or integrating their services can rely on TypeSpec to generate compliant manifests, maintain OpenAPI accuracy, and connect securely into Microsoft 365’s AI ecosystem.

Get started

Developers can explore documentation, review built-in decorators and capabilities, and use the Microsoft 365 Agents Toolkit for guided workflows. The Copilot Camp lab offers a hands-on starting point for building with TypeSpec and declarative agents.

Microsoft says it is excited to see how developers leverage TypeSpec to build the next generation of Copilot-powered solutions.