GitHub Copilot SDK became the Microsoft Copilot SDK, and the Copilot harness reached Foundry Agent Service in public preview

Archive entry: this covers an event from October 28, 2026, and we published it on November 8, 2026. The details come from sources dated at the time and may have changed since.

On October 28, 2026, GitHub announced in a changelog entry on the SDK rename that the GitHub Copilot SDK was becoming the Microsoft Copilot SDK, the programmable interface to the Microsoft Copilot harness. The SDK repository was to move to the Microsoft organization in phases, and no immediate changes were required from users.

What changed

• On the same day, Microsoft put the Microsoft Copilot harness into Foundry Agent Service in public preview, as a managed way to build agents that reason, use tools and complete long-running tasks.
• Microsoft ran the agent loop and sandbox, while developers brought knowledge, procedures and tools.
• The preview included reusable skills, connected Foundry and MCP tools with configured authentication and approvals, execution with delegation to built-in subagents, and source-controlled agent definitions.
• During the preview, the harness had to be selected when an agent was created. Existing agents were unchanged, and switching harness later was not supported.

What it meant for builders

The agent loop behind GitHub Copilot became a Microsoft-wide platform, so developers could build their own agents on the same harness through the SDK or Azure.

Billing and other sources

Harness billing was set to start on December 1, 2026, with consumption pricing. Runtime use was free before then, while model inference and separately billed tools were still charged. From December 1, sandbox compute was priced at $0.0994 per vCPU-hour and memory at $0.0118 per GiB-hour, and prices could vary by region and agreement.

Long-running resilience for hosted agents became generally available the same week. Microsoft covered the preview in its announcement of the Microsoft Copilot harness in Foundry Agent Service and in its Microsoft Foundry roundup for October 2026.

Sources

• GitHub Copilot SDK is becoming Microsoft Copilot SDK (GitHub, October 28, 2026, official)
• Introducing the Microsoft Copilot harness in Foundry Agent Service (Microsoft, October 28, 2026, official)
• What's new in Microsoft Foundry | October 2026 (Microsoft, November 5, 2026, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.