Copilot Agent Builder is the quick, no-code way to build declarative agents inside Microsoft 365. You describe what the agent should do, point it at knowledge such as SharePoint content or Copilot connectors, test it and share it. It's built for quick, straightforward projects; anything that needs to take actions in outside services has to move to Copilot Studio.
Microsoft's own examples are a writing and presentation coaching agent and a team onboarding agent. Think of it as the right tool when you want Copilot to answer from a known set of documents, in a particular way, every time. Here's where it works, the limits people hit on day one, and when it's time to move up.
Declarative is Microsoft's word for an agent where you declare the instructions and knowledge, and Copilot supplies the rest: these agents use Copilot's own AI infrastructure, model and orchestrator, so you're not hosting anything yourself. That's what keeps Agent Builder simple, and it's also why its limits look the way they do.
Where you can open Agent Builder
- Microsoft 365 Copilot Chat on the web, at microsoft365.com/chat or office.com/chat.
- The Teams desktop app.
- Teams on the web.
It isn't available on mobile, so building happens at a desk. You also need a Copilot licence or subscription, and your tenant settings have to allow it: people can create declarative agents in Agent Builder, or in SharePoint, only if those settings are switched on. Admins can turn Agent Builder off entirely.
There's a technical catch too. Agent Builder needs access to *.api.powerplatform.com over HTTPS. If your firewall blocks that address, Agent Builder can fail without anyone in the business realising why, so it's worth telling IT before you start.
The limits to know before you build
| Limit | What happens |
|---|---|
| Teams chats | Agents can't be used in Teams group chats or 1:1 chats |
| Mobile | Agent Builder isn't available |
| Actions in external services | Not supported; copy the agent to Copilot Studio |
| SharePoint auto-sharing | Only to specific security groups, not everyone |
| Customer Managed Keys | Not supported |
The two that catch people first are Teams chats and sharing. Agents built here can't be used in Teams group chats or 1:1 chats, which is often exactly where people want them. And when an agent auto-shares its SharePoint content, it can only share with specific security groups, not everyone in the organisation. Customer Managed Keys aren't supported either, which matters if your security team insists on them.
How to build your first agent
- Open Copilot Chat in Microsoft 365 on the web, or open Teams on desktop or web.
- Start a new agent in Agent Builder.
- Describe what the agent should do, who it's for and how it should respond.
- Add its knowledge: SharePoint content or Copilot connectors.
- Test the agent before anyone else uses it.
- Share or publish it, using specific security groups if it relies on SharePoint content.
Microsoft's own examples point to the sweet spot: an onboarding agent that answers new starters' questions from your handbook, or a coaching agent that gives feedback on writing and presentations against your house style. Because sharing only reaches specific security groups, ask IT to set up a group for the team the agent serves before you publish. It saves a round of messages from people who can't open it.
What Agent Builder agents cost to run
Two details make these agents cheap to run. They don't consume your tenant's Dataverse storage entitlement. And Copilot Studio's billing rules say generative-answer charges don't apply to agents built in Agent Builder when the response doesn't use tenant graph grounding, meaning it isn't drawing on your organisation's wider Microsoft 365 data.
So a simple agent that answers from its own SharePoint knowledge stays inside what you already pay for, which is a good reason to start here before you go near anything usage-billed.
When to move up to Copilot Studio
Agent Builder doesn't support authoring actions that integrate external services. If your agent needs to do something, such as create a record in another system or kick off a workflow, Microsoft's advice is to copy the agent to Copilot Studio, where you can add low-code actions, connectors and workflows. My explainer on what Copilot Studio is covers what changes when you make that move.
Most people will meet the agents they build inside Microsoft 365 Copilot Chat, so it's worth knowing what Chat can already do without an agent before you build one.
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Agent Builder or something bigger?
Start in Agent Builder for anything that's mostly answering questions from your own documents: onboarding, style guides, policy questions. Check the Teams limit first, because if your people live in group chats, they'll be frustrated when the agent can't follow them there. Move to Copilot Studio the day you need the agent to do something rather than just say something.
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Frequently asked questions
What is Copilot Agent Builder?
Agent Builder is Microsoft's tool for building declarative agents inside Microsoft 365. It's designed for quick, straightforward projects, using knowledge such as SharePoint content and Copilot connectors.
Where can I use Copilot Agent Builder?
You can build agents from microsoft365.com/chat, office.com/chat, and the Teams desktop and web client. Agent Builder isn't available on mobile.
Can Agent Builder agents be used in Teams chats?
No. Agents built in Agent Builder can't be used in Teams group chats or 1:1 chats.
What's the difference between Agent Builder and Copilot Studio?
Agent Builder makes simple declarative agents and doesn't support actions that integrate external services. For low-code actions, connectors or workflows, you copy the agent to Copilot Studio.
Do Agent Builder agents use Dataverse storage?
No. Microsoft says agents built in Agent Builder don't consume the tenant's Dataverse storage entitlement.
Can admins turn off Copilot Agent Builder?
Yes. Admins can turn Agent Builder off, and it needs access to *.api.powerplatform.com over HTTPS to work.
Do I need a licence to use Copilot Agent Builder?
Yes. Creating declarative agents in Agent Builder or SharePoint requires a Copilot licence or subscription, and your tenant settings must allow it.
