Microsoft opens the GitHub-built Copilot harness to developers in Foundry Agent Service (public preview)
Microsoft now lets developers build agents on the same orchestration loop that powers GitHub Copilot, Copilot Studio and the Copilot CLI, hosted in Foundry Agent Service. You supply skills, MCP or Foundry tools and instructions; Microsoft runs the loop, sandbox and subagents. Runtime is free until billing starts on December 1, 2026.
Why it matters
A production-tested agent loop with skills, MCP tools and a managed sandbox, so teams can skip building their own harness. Harness choice is fixed at agent creation in preview.
How to try it
Create a Foundry agent that uses the Copilot harness. You define a SKILL.md skill and an azure.yaml agent entry that sets the harness type, model deployment, tools and instructions, then deploy and invoke it with the Azure Developer CLI.
- Create a skill folder with a SKILL.md file that gives the skill's name, description and procedure.
- In azure.yaml, describe the skill and an agent entry: harness type, model deployment, skills, instructions and tools (the example uses web search and Code Interpreter).
- Set the required environment values for your Foundry project.
- Deploy with azd deploy --all, then call the agent with azd ai agent invoke (example from Microsoft's launch post).
azd deploy --all
azd ai agent invoke research-brief \
"Compare publicly announced approaches to agent interoperability.
Produce a concise brief with sources, tradeoffs, and open questions."