One harness, every model
Microsoft gave the plumbing under Copilot a name this week, then opened it. The harness GitHub built now runs Copilot Studio, VS Code and your Foundry agent.
One harness, every model
Microsoft standardised on one agent harness this week, opened it in Foundry, and shipped the router that picks models for you. The orchestration code you were going to write is now a product with a price list.
Signal of the week
The harness behind Copilot is yours to build on
Foundry Agent Service opened the Microsoft Copilot harness in public preview on 28 October. It is the execution layer GitHub built and Microsoft adopted for Copilot Code, Copilot Studio, the GitHub Copilot app, the CLI and VS Code. You declare skills, MCP tools and subagents; Microsoft runs the agent loop and the sandbox.
Why it matters
Runtime is free until 1 December, then billed per vCPU-hour. I would put a real agent on it while the meter is off. I have not pushed it hard yet.
1The router picks the model now
Copilot Fusion is generally available
GitHub Copilot Fusion reached general availability on 28 October. You choose an effort level, not a model, and Copilot routes each task: one model alone, a cascade that escalates a weak draft, or a critique pass where a second model reviews. GitHub scores Fusion Max at 60 on the Artificial Analysis Coding Agent Index.
Why it matters
Two points behind Claude Code with Opus 5.5 Max, by GitHub’s own count. At about half the cost per task. Paid plans get 30 percent off model costs for now.
GitHub Enterprise now includes Copilot
Enterprises working through a GitHub or Microsoft account team now get Copilot included with GitHub Enterprise for every licensed user. There is no seat count to reconcile against usage: consumption meters against the enterprise budget from the first request. Code completion keeps working with no budget left. Chat and code review need budget.
Why it matters
Self-serve comes in stages, so this is an account-team conversation for now. Every enterprise I have sized a rollout for asked the seat question first; it just changed shape.
2And the agent got a face
Copilot UX components are generally available
SharePoint Framework 1.24 makes Copilot UX components generally available. An agent can render a real interface in the Copilot canvas: dashboards, forms, approvals and live business data, inline or full screen, light or dark. Components implement the MCP Apps model, Microsoft 365 hosts them, and React or plain JavaScript both work.
Why it matters
This is the ceiling I kept hitting with Adaptive Cards. Your existing web code and business rules go in, and your code still owns the confirm step before anything changes.
Agents stream in group chats, channels and meetings
Teams released streaming for agents in group chats, channels and meeting chats on 28 October. Until now agents streamed only in one-to-one chat. Informative updates now sit under the message the agent is answering, so a busy channel shows which request is in progress.
Why it matters
Adoption is small but real: update the Teams SDK, or set replyToId on the REST call. My channel agents used to sit silent and people assumed nothing was happening.
3Also this week
- QuickGitHub Agentic Workflows reached general availability.
- QuickThe GitHub app in Microsoft Teams reached general availability: notifications and Copilot in one app, with MCP tool configuration.
- QuickThe GitHub Copilot SDK is being renamed the Microsoft Copilot SDK.
- QuickCopilot Fusion can now use local models you select.
- QuickLong-running resilience for hosted agents in Foundry reached general availability, so work spanning hours resumes from your last checkpoint.
- QuickMicrosoft shipped a credential you earn through everyday product use, with no exam to sit.
- QuickFrontier now gathers public previews for Teams, Outlook, OneDrive and SharePoint behind one admin enrollment.
- QuickCopilot Studio and Defender XDR both still date their newest entries September: a genuinely quiet week on both.
Voices to follow
- Microsoft Software Engineer - CoworkBas Brekelmans
Software Engineer at Microsoft, started the Copilot Cowork project and previously CTO of Copilot Studio. The clearest voice on why Microsoft chose multi-model, MCP, and A2A architecture across the agent stack.
Microsoft Software Engineer, Cowork - ex-CTO Copilot Studio - Microsoft Senior Software Engineer - Agent FrameworkEduard van Valkenburg
Senior Software Engineer on Microsoft's Agent Framework and Semantic Kernel for Python. He ships and documents the Python side of the framework, including the vector stores and context providers that agents use for retrieval.
Microsoft Senior Software Engineer - Agent Framework - Microsoft VP - Product, Microsoft FoundryYina Arenas
Vice President of Product for Microsoft Foundry. She owns the developer surface where hosted agents, the agent catalogue and the Foundry tooling story get decided, and she posts the roadmap thinking behind them.
Microsoft VP - Product, Microsoft Foundry - Microsoft Principal SWE - Agent FrameworkEvan Mattson
Principal Software Engineer in Microsoft's CoreAI Tools and Platform org, working on the Microsoft Agent Framework (Python), multi-agent workflows, and production orchestration patterns. Follow him for the SDK-level detail under the agent stack.
Microsoft Principal SWE - Agent Framework (Python) + orchestration - Microsoft Principal Cloud Developer Advocate - AISeth Juarez
Principal Cloud Developer Advocate at Microsoft on AI. One of the most watchable explainers of Foundry, the Agent Framework, and GitHub Copilot for developers - deep technical content that stays accessible.
Microsoft Principal Cloud Developer Advocate - AI - Microsoft VP of Product - Copilot StudioJason Moore
Vice President of Product for Microsoft Copilot Studio, after 26 years at Microsoft on Windows, OneDrive and SharePoint. He announced agent accounts and business process memory, the shift that turns an agent into something an organisation staffs rather than prompts.
Microsoft VP of Product - Copilot Studio - Microsoft Partner Director - Foundry Agent ServiceJeff Hollan
Partner Director of Product at Microsoft, leading the Foundry agent platform: Agent Service, the Agent Framework, and the SDKs. The clearest source on how agents actually go from prototype to a hosted production runtime.
Microsoft Partner Director - Foundry Agent Service + Agent Framework - Microsoft Cloud Developer Advocate - Copilot extensibilityPaolo Pialorsi
Cloud Developer Advocate at Microsoft for Microsoft 365 Copilot. He writes the developer-facing record of Work IQ and Copilot extensibility, including the retrieve tool that replaces hand-built search layers in agents.
Microsoft Cloud Developer Advocate - Copilot extensibility
Coming up
- 17 to 20 November 2026 · Microsoft Ignite, San Franciscothe harness roadmap should firm up there.
- November 2026 · Computer use for web browsing on the Copilot harness, public previewworldwide multi-tenant only.
- 1 December 2026 · Consumption pricing starts for the Copilot harness in Foundryruntime is free until then.
- January 2027 · That same computer use capability reaches general availabilityper the roadmap entry.
This week's question
If one harness runs Copilot Studio, VS Code and my Foundry agent, does a model swap become a non-event or a change nobody scheduled? I lean non-event, because the routing gets evaluated centrally. I do not know yet.
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