Foundry Toolkit for VS Code

The extension brings Microsoft Foundry development tools into Visual Studio Code, including model and agent workflows. Microsoft describes it as a way to build, test, and deploy generative-AI applications from VS Code ([official overview](https://code.visualstudio.com/docs/intelligentapps/overview)).

The catalog entry positions it for building LangChain agents and LLM applications within VS Code. Microsoft documentation also describes framework choices such as Microsoft Agent Framework and LangGraph, so the exact workflow depends on the installed toolkit version.

Yes, the toolkit includes testing and playground-style workflows for AI applications and agents. That lets a developer inspect behavior in Visual Studio Code before sending the application to a hosted environment.

The extension is described as free and open source, but the AI models or hosted services connected to it may have separate usage terms. Installing the VS Code extension does not automatically make every model or deployment endpoint free.