a skill for your coding agent

Stop guessing at prompts.
Run real experiments.

ImproveFast is a skill your agent runs on its own. Tell it what you want to test and how to judge a good result, and it tries the options, scores each one, and tells you which one wins.

bash
$ npx skills add goodfoot-io/improve.fast

skill via skills.sh · works with your coding agent · no signup

experiment: summary-promptwinner called
prompt-a
9 tries · avg 0.61
prompt-b
21 tries · avg 0.81 · winner
prompt-c
12 tries · avg 0.68

example run — solid marks are scored tries; dashed slots are tries the losing options never needed.

the problem

Right now, improving an AI system means guessing

You tweak a prompt, read a few outputs, and ship it. But AI outputs aren't the same every time, so one good or bad response doesn't really tell you anything. Manual A/B tests take a long time and waste effort on the option that's already losing. And most teams don't have time to build a whole testing setup just to check if a change actually helped.

Finds the winner faster

A plain 50/50 test keeps sending tries to the option that's already losing. ImproveFast shifts more tries to whatever is winning as it goes — in our own test, 90 of 100 tries went to the better option automatically.

Tells you when it's sure

ImproveFast can tell the difference between a real improvement and plain luck. It waits until it's confident before calling a winner, so your agent isn't guessing either.

No testing setup needed

You don't need to build anything. Your agent just scores each try from 0 to 1, and ImproveFast handles the rest.

how it runs

Your agent runs the whole test

ImproveFast gives your agent a simple loop to follow: try an option, do the work, score how well it went using rules you agreed on, and repeat. Scoring each try, again and again, lets it tell a real improvement apart from random luck — something a single side-by-side comparison can't do. You never have to think about the math. You just decide what to test and how to judge it.

01

You pick what to test

Tell your agent which options to compare — prompt wording, strategies, or settings — and agree on how to score a result from 0 to 1.

02

Agent tries an option

The agent picks an option to try next, leaning toward whichever is winning so far without ignoring the others, and does the work.

03

Agent scores it

Each try gets a score using the rules you agreed on. Scoring again and again is what separates a real improvement from luck.

04

Agent reports the winner

Once it's sure enough, the agent reports the winner with the tries and average scores behind it. You decide whether to use it.

what changes

Before vs. after ImproveFast

Before

  • ×Ship a prompt change and hope it's better
  • ×Manual A/B tests waste effort on the losing option
  • ×You need a stats background to call a winner

After

  • Your agent runs a real test as it works
  • More tries go to the winning option automatically
  • ImproveFast calls the winner for you

when it fits

When ImproveFast fits best

  • You have a few options to compare and a way to score each one.
  • You find out how well something worked quickly — seconds or minutes, not days.
  • You want a real answer, not a guess.
  • !Skip it if results take a long time to show up, or if mistakes are costly to safety.

worth testing

Things worth testing this way

  • Different ways of wording a prompt
  • How your agent plans and takes action
  • Model or setting choices (like temperature)
  • How you describe a tool to your agent
  • How you pull in and format background info
  • Structured output vs. free-form text

quick start

One skill install. No servers to run.

Install the skill once, then just talk to your agent — describe what you want to test and how to judge it. No account, no API keys — the agent handles the rest. See the installation guide for prerequisites and verification.

bash
$ npx skills add goodfoot-io/improve.fast

30-second setup · hosted service · free to use

faq

Frequently asked questions

How long until I see a winner?

The leading option usually needs around 15 or more scored tries with a clear, steady lead before ImproveFast will call it — most tests wrap up well before the 50-tries-per-option limit. If your agent scores a handful of tries an hour, expect an answer within a session or two, not weeks.

Is my data private?

Yes. Each test is kept separate by its own ID and is deleted automatically after 7 days. ImproveFast is built for quick tests, not long-term tracking, so your data doesn't stick around any longer than it needs to.

What if I have more than two or three options to test?

That's fine — ImproveFast works with any number of options. More options need more tries to sort out, but it spends most of its effort on the promising ones instead of splitting attention evenly across all of them.

What does ImproveFast actually improve?

Exactly what you and your agent agree to score — nothing more. That's why clear, consistent scoring rules matter so much: if the scores are inconsistent or vague, the result won't be trustworthy either.