Building a prompt library you own

There are four or five prompts you use most weeks, refined over months, currently saved inside the account you are closing. None of them have a portable format and all of them are pure text.

That combination means the work is small and the payoff is permanent, provided you write them somewhere that is not a product.

First, find out what you actually have

Two sources, and the second is the one people forget.

The saved-prompt feature of the old account is the obvious one — whatever it is called there, go through it and copy the text out. Expect a surprise: most people have saved a dozen and use four, and the other eight are experiments that never became habits.

The second source is your conversation history. Prompts you reuse without saving are the ones you type from memory every time, and they appear over and over in the archive. If you have already flattened the export into searchable text, searching for your own opening phrases surfaces them in a few minutes.

The prompts you never saved are usually the ones you use most. Saving is a deliberate act; typing something out of habit is not.

Sort by whether you would notice it missing

Three piles, and the sorting takes ten minutes.

Used weekly. These are the library. Usually a handful.

Used occasionally but genuinely. Keep them, in a second section, without polishing.

Saved once and never used. Do not migrate these. A switch is the cheapest opportunity you will ever have to not carry something forward, and rebuilding an unused prompt costs the same as rebuilding a used one.

Write them into one file

One plain-text file. Not a note in an app, not a document in the product you are moving to — a file, in the same folder as your instruction file and your reference documents.

A workable shape for each entry:

## Weekly status summary

WHEN: Friday, from the week's notes
FILL IN: [notes]

---
Summarise the following week's notes as five bullets,
each one sentence, ordered by how much someone else
needs to know it. Do not editorialise.

[notes]
---

Three things are doing work there. The heading makes it findable. The WHEN line records the trigger, which is the part you forget first. And the delimiters mark exactly what to copy, so using the prompt is a selection rather than a reconstruction.

Use explicit placeholders

[notes], [document], [client name] — square brackets, named, consistent across the library.

This is not decoration. A prompt with the variable part unmarked gets pasted with last week’s content still in it, and that mistake is invisible until the output is wrong in a way you did not expect. A bracketed placeholder is a thing you cannot fail to notice.

Keep the placeholder names consistent so you develop the habit of scanning for brackets before sending.

Rewrite the product-specific parts

Prompts accumulate phrasing aimed at one product’s habits: instructions not to add a preamble, requests for a particular formatting convention, corrections for a tendency you were working around.

Those workarounds are not portable, and pasting them into a new assistant carries over a fix for a problem that may not exist there while hiding whatever the real behaviour is. Strip them on the way into the file and keep only what states the task.

You will add new workarounds on the new side. Add them as a marked line at the bottom of each entry, so that next time you can tell the task apart from the accommodation.

What moves

WHAT MOVES — the prompt library

  · Prompt text
                    → moves. It is plain text and always
                      was.

  · The saved-prompt feature itself
                    → STAYS BEHIND. Structure, folders,
                      shortcuts, sharing — none of it
                      has a portable form.

  · Prompts you never saved
                    → STAYS BEHIND unless you dig them
                      out of the history first.

  · Product-specific workarounds
                    → STAYS BEHIND deliberately. Strip
                      them; they fix a behaviour you are
                      leaving.

  · Deleting the old saved prompts
                    → IRREVERSIBLE. Copy them out before
                      touching the account.

Then load them in on the new side

Whatever the new assistant offers for saved prompts, populate it from the file — not the other way round. The file stays authoritative; the product’s copy is a convenience.

The discipline that makes this hold: when you improve a prompt in use, improve it in the file too, same day. A library that drifts out of date is worse than none, because you will trust it and paste something you fixed three months ago.

Test each one before you rely on it

Run every weekly prompt once against real input during the parallel period. Not to compare the outputs, but to find the entries that assumed something about the old product and quietly do nothing now.

Fix them in the file. Ten minutes, and it is the difference between a library and a folder of text you hope still works.

What is genuinely lost

The tuning history. You know these prompts work; you no longer know why each clause is there, and the sequence of small corrections that produced them is not written down anywhere. Rewriting from the finished text means some clause you no longer understand gets dropped, and you find out which one later.

That is a real and unavoidable cost, and it is a cost you pay once. From here the library is a file you own, and the next switch does not involve rebuilding it at all.