Make slow code faster and prove it with before and after numbers
Give it what feels slow. Get the cause ranked by cost, a fix, and before and after timings.
Find what is slow, fix it and show the numbers is a free AI workflow for the job "Test and fix code". It guides your AI through several skills in order, passing each step's output to the next.
Free · No account · Made by AI Blocks
What it does
When something feels slow, people guess. They add a cache, rewrite a loop or buy a bigger server, and the slow part stays where it was. Without numbers nobody can say whether the change helped. The steps here start with the clock. The first writes the slow moment in one line, plans the timings, looks at the worst runs and ranks each stage by the time a fix would save. It also lists the ideas the numbers rule out. You then run the timings it planned and note the top stage. The second step measures that stage in the code, fixes it and measures again. The last writes the pull request with the before and after timings, so a reviewer can see the gain.
You give it
- What is slow, when it happens and about how long it takes
- Access to your project code
- Logs, timings or a slow-query list (optional)
- Your target speed (optional)
- Your results (optional)
You get
- The slow moment written in one line, with the stages ranked by what they cost
- A list of ideas the numbers rule out, so you skip them
- The biggest bottleneck fixed in code, measured before and after
- A pull request that shows the timings
Use it when
- A page, report, job or query feels slow and the team is guessing why.
- A speed fix was tried and nobody can say if it worked.
- You need numbers to show a reviewer or a client.
Steps
- App performance investigation planner: Describe what feels slow. Get a measurement plan, the worst-case view and a ranked fix list.
- Slow code fixer: Describe what feels slow. Get the bottleneck found, fixed, and proven faster with before and after numbers.
- Pull request writer: Give it your changes. Get a clear pull request description a reviewer can follow.
How to use it
- Download the handoff pack. It's a zip with HANDOFF.md and every skill file this workflow uses.
- Open your project in Claude Code, give it the folder and say "Follow HANDOFF.md".
- Describe what is slow and how long it takes. Add any logs you have.
- Run the timings the first step plans. Tell it the numbers for the top stage.
- Check the before and after figures in the pull request on a run of your own.