Build Your Own Assistant: Projects and Custom GPTs
⚠️ Version note: menu names for these features move around. The idea — persistent instructions plus persistent files — is stable. Last checked: 24 July 2026.
You've been retyping the same paragraph for six months
Open a new chat. Explain who you are. Explain what you're working on. Explain how you want the answer shaped. Paste the same three background facts you pasted last Tuesday.
Then do it again tomorrow.
This is what most people's AI use looks like, and it caps the tool at roughly a search engine that writes. Everything genuinely useful — an assistant that already knows your codebase's conventions, your course's marking criteria, your client's tone — requires context you're not willing to retype every single time. So it never gets given, and the output stays generic.
An assistant is just that paragraph, stored. The feature is unglamorous and the payoff is enormous, which is roughly the definition of the thing everyone skips.
What you'll have at the end
- Three working assistants, for three jobs you genuinely repeat
- An instruction pattern that survives contact with real use
- A sense of which jobs deserve one and which don't
Prerequisite: AI-02 (you'll need to have set one up once) and AI-04 (the instructions are a prompt — the five parts do the work here).
Pick jobs that actually repeat (8 min)
Wrong choices here waste the whole lesson. The test is simple:
Have I done this more than three times, and will I do it again this month?
Assistants pay off on frequency, not importance. A one-off task, however big, is better served by a single well-built prompt.
| Good candidates | Bad candidates |
|---|---|
| Essay/report drafting for one specific course | "General help" |
| Code review against your project's conventions | A single assignment |
| Turning lecture notes into practice questions | "Be creative" |
| Cover letters for one type of role | Anything you'll do once |
| Explaining a subject you're learning, at your level | A vague "study buddy" |
The most common failure is one giant do-everything assistant. It ends up with contradictory instructions and gets worse at all of them. One assistant, one job. Three narrow ones beat one broad one, reliably.
✅ Check: three jobs written down, each passing the "more than three times" test.
The rest of this walkthrough is for members
Behind this: the full step-by-step, the exercise with a verifiable output, and the downloadable cheatsheet. Everything you've read above stays free, always.