What this actually is
Prompt Master is a Claude skill. You describe what you want in whatever shape it comes out of your head, and it hands back a single clean prompt you can paste into any AI tool. It is free, MIT licensed, and it installs from a browser in about a minute with no terminal.
The thing worth understanding before you install it is what it is optimising for. Most prompt tools make prompts longer. This one makes every word load bearing, which is the repo's own phrase, and then strips the rest. The output is usually shorter than what you would have written by hand and far more specific.
- Repo: github.com/nidhinjs/prompt-master
- 11,415 stars, MIT licensed, verified 19 August 2026
- Works with Claude, Claude Code, ChatGPT, Gemini, Cursor, Windsurf, Copilot, Midjourney and about thirty more
The cost you are not counting
Almost nobody wastes credits on the answer. They waste them on the conversation that follows it.
- You write a rough prompt, because writing a precise one takes longer than you want to spend.
- The model does exactly what you asked, correctly, and it is not what you meant.
- You spend three more messages explaining what you actually meant.
- Attempt four is the one you keep.
That is four passes for one result. You paid for the first attempt, then you paid again to describe the first attempt, then again. Each of those feels like a small correction rather than a bill, which is exactly why the total is invisible. Multiply by however many prompts a day you send.
The failure is almost never the model being wrong. It is the model being right about a request that was underspecified: no definition of done, no scope boundary, no stack, no stop condition. It cannot ask you for those, so it guesses, and a guess is what you end up correcting.
The four things it adds that you were never going to write
This is the part that matters and it is easy to skim past. For agentic tools the skill emits four things by default, and those four are the ones people leave out by hand every single time.
- What the output should look like. Not "make it good" but the actual shape of done: the format, the length, the sections, the acceptance criteria. The repo calls the missing version of this "no success criteria" and it is the single most common pattern it catches.
- Which files it is allowed to touch. And, more usefully, which it is not. Scope is a fence, and a fence only works if it has an outside.
- When to stop. An explicit stop condition, plus checkpoints, so an agent reports progress instead of running until it decides it is finished.
- What was already decided. A Memory Block of prior choices carried forward, so the model does not contradict architecture you settled two days ago.
If you write those four yourself, every time, you do not need this skill. Almost nobody does, which is the whole point.
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Get the full setup steps + the copy-paste setup prompt
The rest of this guide (5 more sections) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.
Unlocks: Install it in about a minute · The 35 patterns it checks every prompt against · The Memory Block, which is the fix for long sessions · It is not a Claude only tool · What to know before you install it
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