Who Built This Before Me

Check whether a project, tool, library, or product idea has already been built before the user invests time in it. Find existing solutions, extract standard patterns, benchmark the user's angle against prior art, and deliver a clear verdict (build / fork / contribute / use existing / investigate why it failed). Use this skill whenever the user describes something they're thinking of building, making, shipping, launching, or coding — especially phrases like "I want to build…", "I'm thinking of making…", "should I build X…", "is there already a…", "my idea is…", or when the user is scoping a new

76 stars 9 forksFinance & Crypto

Install

skills CLI (Claude Code, Cursor, Codex and more)

npx skills add iagochavarry/who-built-this-before-me --skill who-built-this-before-me

Manual install

git clone --depth 1 https://github.com/iagochavarry/who-built-this-before-me.git /tmp/who-built-this-before-me
mkdir -p ~/.claude/skills
cp -r /tmp/who-built-this-before-me/. ~/.claude/skills/who-built-this-before-me

Personal skills live in ~/.claude/skills. Use .claude/skills in a project folder to share a skill with your team.

From the SKILL.md

# who-built-this-before-me
 
Before the user burns a weekend (or a quarter) building something, find out whether it already exists. Most ideas have been tried. Some are solved well, some are solved badly, some failed for instructive reasons, and a few are genuinely open. This skill figures out which bucket the user's idea falls into and tells them plainly.
 
## Core loop
 
1. **Restate the idea in one sentence.** Strip the pitch down to: what it does, who it's for, what constraint makes it distinctive (if any). Show this back to the user and confirm before searching. If the idea is too vague to search (i.e. the framing matches an entire tool category), ask exactly **one** clarifying question. You may include up to 3 example dimensions as prompts, but no more — this is a question, not a questionnaire.
2. **Generate vocabulary before searching.** Before running any query, write down 6–10 different framings of the idea from distinct vantage points. The user's framing is one lens; other builders, academics, and infrastructure people use different words for the same thing. Cover at minimum:
   - The builder's framing (the user's own words)
   - The user-of-the-tool framing (wng for this would type)
   - The academic or research framing (if applicable)
   - The infrastructure / implementation framing
   - The adjacent-community framing (the next-door discipline that likely solved this first)

Read the full skill on GitHub

Details

Skill name: who-built-this-before-me
Repository: iagochavarry/who-built-this-before-me
License: MIT
Repo updated: 18 April 2026

FAQ

What does the Who Built This Before Me skill do?

How do I install the Who Built This Before Me skill?

skills CLI (Claude Code, Cursor, Codex and more): npx skills add iagochavarry/who-built-this-before-me --skill who-built-this-before-me. Skills go in ~/.claude/skills (personal) or .claude/skills (project), and Claude loads them automatically when a task matches the description.

Is Who Built This Before Me popular?

It lives in iagochavarry/who-built-this-before-me, which has 76 GitHub stars and 9 forks.

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