Ask the tool. It knows where it lives.
The simplest way, and the one that never goes out of date: paste your BRIEF into whatever AI you already use and ask it how to turn this into an agent. It will tell you where the box is, step by step, in the version of the tool you are looking at.
Sean did this with a school administrator this week. The administrator asked how to make a Gem. Sean said: just ask Gemini the best way to turn this into an agent. Gemini tightened the BRIEF a little, gave him step by step instructions for where to paste it, and taught him how to build his own.
What you type stays in this browser. There is no server, no account, and nothing is sent anywhere until you decide to send it.
Your BRIEF
The ask, ready to paste
Let it ask. The questions it comes back with are your first look at how it thinks, and every one of them is something the BRIEF should have said. Fix the BRIEF, then build the agent. That is Feedback, started before the agent exists.
If you want to see the clicks first
Pick the tool you already have. These were checked against each company's own help pages on the date at the bottom. They change. If one of them has moved, tell sean@rewirecompany.com and it gets fixed. Or ask the tool.
Claude: A Project
Where it lives
A Project. Every chat inside the project reads the instructions you set for it, and the files you add to it.
The clicks
- Go to claude.ai/projects and click + New Project. Give it a name.
- Click Set project instructions. Paste your BRIEF. Click Save instructions.
- Use the + button in the project knowledge panel to add the documents the Background points at.
- Start a chat inside the project. That is the agent.
What to know
- Projects are on every plan, including the free one. Free accounts get up to five projects.
- There is no published character cap on the instructions. A whole BRIEF fits.
What happens to what you paste
On the personal plans (Free, Pro, Max), whether your chats are used to train Claude is a setting you choose in Privacy Settings. Check it. Team and Enterprise plans are not used for training.
Who can do this
Free plan and up. Team or Enterprise for company data.
ChatGPT: A Project
Where it lives
A Project, with your BRIEF in the project instructions. Not a custom GPT: new GPTs can no longer be made on personal accounts, and OpenAI has scheduled custom GPTs to retire on 11 December 2026.
The clicks
- In the sidebar, create a new project and name it.
- Open the project's menu (the three dots), choose Project settings, and paste your BRIEF into the instructions.
- Add files to the project. Free accounts get 5 files per project, Go and Plus get 25, Pro and the business plans get 40.
- Chat inside the project. That is the agent.
What to know
- Custom GPTs: existing ones still run, but Free, Go, Plus and Pro accounts cannot create new ones, and OpenAI plans to end creation on every plan on 26 October 2026. All of them retire on 11 December 2026 (11 February 2027 for Enterprise workspaces with an approved deferral). In Business, Enterprise and Edu workspaces the replacement is a Plugin, where the instructions become a skill.
- There is no published character cap on project instructions.
What happens to what you paste
On Free, Go, Plus and Pro, your chats are used to train OpenAI's models unless you turn off "Improve the model for everyone" under Settings, Data controls. Business, Enterprise and Edu workspaces are not used for training by default.
Who can do this
Free plan and up. A workspace plan for company data.
Gemini: A Gem
Where it lives
A Gem. Your BRIEF is the Gem's instructions.
The clicks
- In the Gemini web app, open Explore Gems in the left panel and click New Gem.
- Name it and paste your BRIEF into the instructions.
- Under Knowledge, click Add files to attach documents from your computer or Google Drive.
- Save it. The Gem sits in your list and every chat with it starts from the BRIEF.
What to know
- Gems are available on the free Gemini app.
- Make the Gem in the web app. Google says some Gem features are not yet in the mobile app.
- No published character cap on the instructions.
What happens to what you paste
On a personal Google account, Gemini Apps Activity is on by default, and Google says it uses that activity to improve its services, including training its models, with human reviewers. You can turn it off in Gemini Apps Activity. Work and school accounts run under Google Workspace terms, which are different. Ask your admin.
Who can do this
Free plan and up. A Workspace account for company data.
Microsoft 365 Copilot: An agent
Where it lives
An agent, made in Agent Builder inside the Copilot app. Your BRIEF is the agent's instructions.
The clicks
- Open the Copilot app at work and choose New agent.
- Describe the agent in plain words, or choose Skip to configure.
- On Configure: a name (30 characters), a description (1,000), and the instructions box, which takes 8,000 characters. Paste the BRIEF there.
- Under Knowledge, point it at up to 20 sources: SharePoint sites, folders, files, or connectors. Then publish it to yourself or your team.
What to know
- The instructions box holds 8,000 characters. Your character count is above.
- You need either a Microsoft 365 Copilot add-on license, or Copilot Chat, which comes with eligible Microsoft 365 subscriptions at no extra charge.
- On Copilot Chat without the add-on, an agent that uses only instructions or public websites adds no cost. An agent that reads SharePoint or a connector can be metered by usage, if your organization turned that on.
What happens to what you paste
A work account, under your organization's Microsoft 365 terms. Your IT admin decides who can build agents and where they can be published.
Who can do this
A work Microsoft 365 account. Ask IT which agents you can build.
One rule that holds in all four: put company or customer information into the business version of the tool, the one under a contract, not into a personal account. On a personal account, check the training setting before you paste anything you would not want reused.
The clicks above were checked against each vendor's help pages on 23 September 2026. The ask at the top does not go stale.
The Rewire Company is here to help make AI work for you. For more information visit our website or contact Sean Glennon at sean@rewirecompany.com.