Otto365 AI Brief #035

Copilot: the harness behind Microsoft's agents is yours to build on

How this was made: Otto365 and Sam are animated characters and their voices are generated by AI. Sam is a fictional small-business owner. The video tells the same story as the text on this page; the transcript lists every spoken word and the main lines shown on screen. Spotted an error?
  • Published
  • By the Otto365 AI Brief. The script was drafted with AI assistance, and every claim was checked against the sources below by our automated checks. Published on under the standing approval of Peter Ferguson, Editor.
  • Announced 28 Oct 2026
  • Voiced by AI

What happened

Microsoft's Copilot harness, the layer running its agents, is yours to build on. Microsoft announced on the 28th of October 2026 that its Copilot harness is available through Microsoft Foundry. The model is the engine; the harness is the car around it: instructions, context, execution environment and controls.1

Three things to know

  1. Runs Copilot Studio First, this harness powers Copilot Studio, the GitHub Copilot app, the CLI and VS Code. GitHub's engineers built it; it lets agents reason, use tools and complete long-running tasks.1
  2. 20+ frontier models Second, it works across at least 20 frontier models, plus bring-your-own-key, and Microsoft says it routes each task to the right model. Models fall behind fast; Microsoft says it keeps up for you.1
  3. Foundry: SDK or cloud Third, developers get it through Microsoft Foundry: download the SDK, or run it in the cloud managed by Foundry. Microsoft runs the agent loop and sandbox with governance built in; you bring instructions, skills, tools and model choice.1

Why it matters to you

Otto365's take (opinion)

So, my take. For UK small businesses this mostly means Copilot Studio agents, not code. You are not locked to one model, and your agents keep improving without you maintaining them.1

Do this week

Try this: list one repeat task for a Copilot Studio agent.

Sources

  1. Microsoft: Introducing the Microsoft Copilot harness: Unlocking the potential of truly multi-model agentic work - The Official... (opens in a new tab) Primary source, accessed 29 Oct 2026
The quotes we checked (15)

  • And today, we’re making that harness available through Microsoft Foundry.

    Microsoft · source 1

  • That gives developers and enterprise customers a fully managed way to build agents that reason, use tools, and complete complex, long-running tasks.

    Microsoft · source 1

  • Oct 28, 2026 | Tina Schuchman CVP, Foundry

    Microsoft · source 1

  • If the model supplies the intelligence, the harness is everything around the model. It’s the orchestration layer that gives an agent the right instructions, context, execution environment, and controls to accomplish meaningful work.

    Microsoft · source 1

  • The Microsoft Copilot harness powers Copilot Code, Copilot Studio, the GitHub Copilot app, the CLI, VS Code, and more.

    Microsoft · source 1

  • the GitHub engineering team built a best-in-class, truly multi-model harness, which we’ve adopted company-wide.

    Microsoft · source 1

  • The harness is built to perform across model families, with 20+ frontier models plus bring your own key, so you can use the right model for the right job.

    Microsoft · source 1

  • Instead of doing the work to keep up with and eval new models, lean on us to intelligently route work to the right model or models based on the task.

    Microsoft · source 1

  • This is a fast-moving space. A frontier model today might fall behind tomorrow.

    Microsoft · source 1

  • And building your own harness or model router to keep up can be painful and slow.

    Microsoft · source 1

  • The SDK is available to download, or you can run the harness in the cloud, all managed by Foundry.

    Microsoft · source 1

  • Microsoft runs the agent loop and sandbox, with governance and optimization built in from day one. You bring the instructions, skills, tools, and model choice.

    Microsoft · source 1

  • You get the right model for the job without switching the harness or the rest of your tech stack.

    Microsoft · source 1

  • our continuous harness improvements will benefit your agents, too.

    Microsoft · source 1

  • Now, you can build on the same harness Microsoft and GitHub ship in our own products, and you don’t have to maintain it.

    Microsoft · source 1

Transcript

Full transcript

Sam: Otto! Copilot's harness is yours to build on!

Play from 0:03 Otto365: I know. Microsoft made its Copilot harness available through Microsoft Foundry on the 28th of October. Sam: What's a harness? Otto365: The model is the engine. The harness is the car around it: instructions, context, execution environment and controls.

Play from 0:18 Sam: Have I already used it? Otto365: It powers Copilot Studio, the GitHub Copilot app, the CLI and VS Code. Sam: Who made it? Otto365: GitHub's engineers built it. It lets agents reason, use tools and complete long-running tasks.

Play from 0:32 Sam: Which AI does it use? Otto365: At least 20 frontier models, plus bring your own key. Microsoft says it routes each task to the right model. Sam: Do I keep up with them? Otto365: Models fall behind fast. Microsoft says it keeps up for you.

Play from 0:47 Sam: How do people get it? Otto365: Developers download the SDK, or run it in the cloud managed by Foundry. Sam: And who does the hard bit? Otto365: Microsoft runs the agent loop and sandbox, with governance built in. You bring instructions, skills, tools and model choice.

Play from 1:03 Sam: I'll code agents tonight! Otto365: My take: for UK small businesses this mostly means Copilot Studio agents, not code. You are not locked to one model, and your agents keep improving without you maintaining them. Sam: I'd already bought a hoodie.

Play from 1:18 Otto365: Keep the hoodie. Try this: list one repeat task for a Copilot Studio agent.

Otto365: I'm Otto365.

Follow the Brief.

On screen

Play from 0:00
Otto365 AI Brief #035, Microsoft Copilot, 28 Oct 2026
Copilot's harness is yours to build on
Instructions
Copilot harness
Right model
Work done
Play from 0:03
Copilot harness in Foundry
Announced 28 Oct 2026
Model: The intelligence
Harness: Instructions; Context, controls
Source: Microsoft, 28 Oct 2026
Play from 0:18
Runs Copilot Studio
Runs on the harness
Copilot Studio
GitHub Copilot app
The CLI
VS Code
Instructions
Reasons
Uses tools
Long task done
Play from 0:32
20+ frontier models
Your task
Harness routes
Right model
Result
Bring your own key
Microsoft keeps up
Play from 0:47
Foundry: SDK or cloud
Download the SDK
Cloud, managed by Foundry
From 28 Oct 2026
Microsoft runs: Loop and sandbox, Governance
You bring: Instructions, Model choice
Play from 1:03
Not locked to one model
Own harness: Painful and slow, You maintain it
Copilot harness: 20+ models, Keeps improving
Instructions
Studio agent
Copilot harness
Task done
Play from 1:18
List one task for an agent
Voiced by AI. Fact-checked against its sources. Apps 365 sells AI and Microsoft 365 services. Not endorsed by companies named.

Voiced by AI. Fact-checked against its sources. Apps 365 sells AI and Microsoft 365 services. Not endorsed by companies named. Report an error.

  1. #019

    Microsoft: the AI agents you deploy are insiders too

    Microsoft says, in a post dated the 19th of October 2026, that AI agents companies deploy themselves are agentic insiders. This week: List each AI agent's access.

  2. #020

    Microsoft: sovereign cloud controls ask who can reach your data

    Microsoft announced new Sovereign Cloud controls on the 20th of October 2026. This week: Ask about Customer Lockbox.

  3. #031 Otto and Sam

    Apple: an AI assistant inside Pages, Keynote and Numbers

    Apple's work apps get an AI assistant, with a UK catch. Apple announced AI features for Apple Creator Studio on the 27th of October 2026. This week: Check your device language.