Microsoft Foundry Agent Service, Three Ways to Run an Agent

Microsoft renamed the platform twice and rebuilt the agent primitive once. Learn the current shape: prompt agents (no infrastructure), hosted agents (your container, their endpoint and Entra identity), and ephemeral agents via the Responses API — plus Toolboxes as one governed MCP endpoint, where Microsoft Agent Framework fits, and how publishing and agent identity actually work.

Content current as of 2026-09.

Lessons

1. Two renames and one rebuilt primitive
2. Prompt, hosted, ephemeral: three ways to run an agent
3. Toolboxes: many tools, one governed MCP endpoint
4. Workflows, and where Microsoft Agent Framework fits
5. Publishing and identity: Entra, Teams, and A2A