Custom Instructions only go so far. For repeatable, structured work, the agent builder in Microsoft 365 Copilot does what Custom Instructions can’t do.
Custom instructions in Microsoft 365 Copilot are genuinely great. Set them once in Copilot Chat and your responses come back in your tone, your format, your audience. Outlook has its own custom instructions too, and they’re just as good – Copilot starts drafting email that sounds like you wrote it.
They’re so good, in fact, that the first thing most people ask is the obvious one: can I do this in Word, Excel, and PowerPoint too? It feels like the natural next step. One setting, applied everywhere.
You can get consistency across repeatable work in Microsoft 365, but not by extending Custom Instructions into every app. The better path is to build an agent for the task you repeat..
Where Custom Instructions Live Today
Two separate settings that are worth turning on:
- Copilot Chat Custom Instructions: Apply only to conversations inside Microsoft 365 Copilot Chat. They don’t change how Copilot behaves in Word, Excel, PowerPoint, or Teams.
- Outlook Custom Instructions: Apply a separate setting inside Outlook. They only shape Copilot responses inside Outlook.
Both are worth setting up. But neither one extends into Word, Excel, or PowerPoint. If the task has the same inputs, the same structure, and the same output every time, Agent Builder is the better tool.
The Scenario: A Weekly Status Report
Most project leads know this scenario by heart: Every Friday, leadership gets a status update. The inputs can be messy:
- Notes pasted from Teams meetings
- Task updates pulled from Planner
- Email follow-ups from stakeholders
- Partial summaries you wrote earlier in the week
The output has to be clean and predictable. Leadership wants the same structure every time:
- Status Summary: one or two sentences
- Key Progress: bulleted, completed work only
- Risks & Blockers: bulleted, include impact
- Decisions Needed: state clearly, or “None”
- Next Steps: bulleted, action-oriented
Every week, you paste in the latest notes, restate the format, and remind Copilot what belongs in each section. That’s the trap: you’re repeating the same instructions by hand instead of turning them into a reusable workflow.
The Better Tool: Agent Builder in Microsoft 365 Copilot
If you have Microsoft 365 Copilot, you can build agents directly from Microsoft 365 Copilot Chat. There’s no separate add-on to buy or custom app to build to get started.
Two things make it the right tool for this kind of work:
- It can work from the content you already have access to in Microsoft 365. That can include emails, Teams chats and meetings, SharePoint sites, and OneDrive files. You still need to give the agent clear instructions about what to pull from and how to use it, but you don’t have to build the data connection from scratch.
- It’s shareable. Build the agent once, share it with your team, and everyone’s status reports follow the same structure. That’s the part Custom Instructions can’t do because they’re personal to you.
Custom Instructions help Copilot match your tone, format, or audience. An agent defines a repeatable job: what inputs to use, what rules to follow, and what the finished output should look like.
What the Weekly Status Agent Looks Like
You don’t write code. You describe it. In the agent builder, you tell Copilot what the agent is for, what it should pull from, and the exact format the output needs to follow. A description for this one might look like:
“You are a weekly status report agent. When the user gives you raw notes from Teams meetings, Planner updates, stakeholder emails, and personal summaries, organize the content into five sections: Status Summary (1–2 sentences), Key Progress (bullets, completed work only), Risks & Blockers (bullets, include impact), Decisions Needed (state clearly or ‘None’), Next Steps (bullets, action-oriented). Keep the tone factual. Do not include work that is in progress under Key Progress.”
That’s the agent. Every Friday, you open it, drop in this week’s messy inputs, and you get a draft in the format leadership expects. No re-prompting. No “remember, the bullets need to be action-oriented.” The agent already knows.
In practice, the workflow is simple: you build the agent once, define the sources and output structure, and then reuse it each week with the latest project inputs. Instead of rewriting the prompt every Friday, you review and refine a draft that already follows the right format.
You can also make the workflow more targeted by telling the agent which sources matter most. For example, you might have it look at a specific Teams channel, a project folder in SharePoint, or stakeholder emails related to the project. The more clearly you define the source material, the more reliable the draft becomes.
The Real Shift: From Prompting to Agents
Custom Instructions are personal settings. They help Copilot sound more like you, but they do not create a shared, repeatable workflow. Agents do. If you keep giving Copilot the same instructions for the same type of task, you’ve found a candidate for an agent.
Weekly status reports are the obvious one. But the same pattern works for customer call recaps, internal newsletters, executive briefings, RFP responses, change request summaries or anything with a defined format and a defined set of inputs.
Build it once. Share it with your team. Stop rewriting it.
Want to Build One With Us?
If you’d rather not figure this out alone, JourneyTeam’s Copilot Agents Sherpa Workshop provides hands-on sessions where you’ll build an agent like the one in this post, from scratch, with our team guiding you. You walk in with messy inputs and a vague idea. You walk out with a working agent your team can use on Monday.
