Save Your Best Instructions: Projects, GPTs and Skills · Lesson 4 of 7

Add reference files

20 minutes. The facts go in files. The instructions say how to use them.

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Your instruction from Lesson 3 says how to write. It shouldn't also have to carry your whole price list. When facts sit inside the instruction, two things go wrong: the instruction gets long and hard to read, and the facts go stale without anyone noticing.

So split them. The instruction holds the how. Reference files hold the what: prices, service lists, warranty wording, a sample finished document. Every tool in this course lets you attach files to a saved instruction.

What makes a good reference file
  • It answers questions the AI would otherwise guess at. Prices, service area, hours, standard wording, product names spelled the right way.
  • It's short and current. A one-page price sheet beats a 40-page catalog from two years ago. The AI will use whatever you give it, including the outdated parts.
  • It's dated. Put "Current as of [date]" on the first line. When the date gets old, someone notices.
  • It's the same file your team uses. If the office already keeps a price sheet, attach that one (or a copy you update at the same time), so there's one set of numbers, not two.

Good first files for the three common instructions:

| Instruction | Reference files that help | |---|---| | Brand voice | Three real emails or posts you were proud of; a short list of words you use and avoid | | Quote or estimate | Current price sheet; standard warranty and terms wording; one finished quote as an example | | Meeting recap | One good past recap; a list of your regular meetings and who usually attends |

What never goes in a reference file

Anyone who can use a saved instruction can often see its files, and some tools let people download them. Treat every reference file as something your whole team, and possibly a contractor, could read.

Keep these out:

  • Customer or patient records, including old quotes with real names and addresses (change them first)
  • Payroll, employee files, Social Security numbers, bank or card numbers
  • Passwords, door codes, Wi-Fi keys
  • Contracts or documents you've agreed to keep confidential
  • Anything you'd be uncomfortable seeing forwarded

If the instruction needs a customer's details, the person types them into the request each time. They don't live in the file.

Format and size: what to look for

Each tool takes files a little differently, and the limits change. A few things worth knowing as of October 2026:

  • Gemini Skills (Gemini app): reference files can only be added by uploading them with the skill. Google lists text, PDF, data and web files as supported, but not Word (.docx) files, and the total upload has a 100 MB limit. Save your price sheet as a PDF or plain text before uploading.
  • Microsoft 365 Copilot Notebooks accept Word, PowerPoint, Excel, PDF, Loop and OneNote pages, and you can pick files from OneDrive.
  • Copilot agents can point at SharePoint files and folders, but only with a Copilot license or pay-as-you-go billing. People only see answers from files they already have permission to open.
  • Claude and ChatGPT Projects take uploaded files in the project's files or knowledge area. Check your plan's limits in the tool if you have lots of files.

The safe default for all of them: a short PDF or plain-text file. Most tools read those well. If a table comes out wrong, a plain list usually fixes it.

Linked files vs uploaded copies

Some tools let you link a live file (a SharePoint document, a Google Drive file) instead of uploading a copy. That's handy: change the file, and the AI sees the change. It also means anyone who can edit that file can change what the AI says.

Uploaded copies are the opposite. Nothing changes until someone uploads a new version. That's safer, but it goes stale quietly.

Either is fine. Just know which one you have, and write it in your master copy.

Tell the instruction how to use the files

Attaching a file isn't enough on its own. Add a line to your instruction that names each file and says what it's for:

> Use the file "Price sheet, current as of October 2026" for all prices. If an item isn't on it, say so and ask; don't estimate. > > Use the warranty paragraph from "Warranty and terms" word for word. Don't summarize it.

Naming the file makes it far more likely the AI uses it, and it tells the next person who reads the instruction which file matters.

Do this now: attach two files (15 minutes)
  • Pick the two facts your first instruction gets wrong most often, or would hurt most to get wrong. For a quote, that's usually prices and warranty wording.
  • Make a clean, short, dated file for each. Remove any real customer details. Save them as PDF or plain text.
  • Put the originals in the same shared folder as your master copy.
  • Upload them to your saved instruction in your AI tool (or link them, if your tool supports that and you're happy with who can edit them).
  • Add one line per file to your instruction, in the master copy first, then in the tool, saying what each file is for.
  • In the master copy's "Reference files" section, list each file, its date, and whether the tool has a copy or a link.

Check it worked

Ask your saved instruction a question only the file can answer, like "What do we charge for [an item on your price sheet]?" It should give the price from the file. Then ask about something that isn't on the sheet. It should say it doesn't know and ask you, not invent a number. If it invents one, tighten the line that says how to use the file.

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Next: proving it works on real requests, not just one quick try.

→ Test it with three real requests

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