From the source
Microsoft introduced the Microsoft Copilot harness in Foundry Agent Service in public preview, a fully managed way for developers to build agents that reason, use tools and complete long-running tasks.
- The harness runs the agent loop and sandbox while developers supply the knowledge, procedures and tools, so teams avoid rebuilding the same execution machinery for coordinating model and tool calls, maintaining working context and managing files.
- The preview brings four building blocks: reusable skills that package instructions, scripts and resources; connected Foundry and MCP tools with configured authentication and approvals; execution and delegation, including file and code work and bounded tasks handed to built-in subagents; and source-controlled agent definitions.
- Microsoft says the harness manages working context as tasks develop and coordinates model and tool steps within configured limits and policy boundaries, and developers can choose a supported Foundry model without rewriting the orchestration around it.
- Microsoft also announced general availability of long-running resilience for hosted agents.
- Confluence Technologies' chief technology officer Chris Evans said the company had a solution running in less than a week, and Fashable's CEO Orlando Ribas Fernandes said the harness gives it a foundation for governed, measurable sourcing workflows.
