Build a singing app that shows exactly where you're off-key
A self-described bad singer got frustrated that his singing app filled up with non-original songs, so he asked Claude Code to build OnKey, which scores pitch against the original recording. His agent researched which audio tools he could use by license and tested them against an eval set.
Source
dsmurrell on Hacker News · 2026-10-22 · Project link
Written in our own words. Credit to the original author. Link checked 2026-10-23.
What they did
A self-described bad singer got frustrated that his singing app filled up with non-original songs, so he asked Claude Code to build OnKey, which scores pitch against the original recording. His agent researched which audio tools he could use by license and tested them against an eval set.
Result (as claimed)
He says it took about 10 days instead of months.
Tools they used
Cost: Claude Code: from $17/mo.
Set it up
Write a one-page brief
Describe the app in plain words: who it is for, the 3 core screens or actions, and what "done" looks like.
Start the project with your agent
Open Claude Code and paste the brief. Ask it to propose a stack and a file plan before writing code.
Build one slice at a time
Ship the smallest working flow first, run it, then add features one by one. Commit after each working step.
Test it like a user
Click through on desktop and phone. Ask the agent to add basic tests and fix anything that breaks.
Check security and ship
Keep keys in environment variables, check auth and database rules, then deploy and share the link.
Copy the full setup prompt
Paste into your agent and it will walk you through the setup, asking before anything that sends, posts or spends.
You are helping me set up this AI use case end to end in Claude Code. Goal: Build a singing app that shows exactly where you're off-key What the original author did: A self-described bad singer got frustrated that his singing app filled up with non-original songs, so he asked Claude Code to build OnKey, which scores pitch against the original recording. His agent researched which audio tools he could use by license and tested them against an eval set. Reported result (as claimed by the author): He says it took about 10 days instead of months. Source: https://news.ycombinator.com/item?id=50195488 Tools they used: Claude Code Category: Vibe coding & apps Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Codex. Goal: Build a singing app that shows exactly where you're off-key What the original author did: A self-described bad singer got frustrated that his singing app filled up with non-original songs, so he asked Claude Code to build OnKey, which scores pitch against the original recording. His agent researched which audio tools he could use by license and tested them against an eval set. Reported result (as claimed by the author): He says it took about 10 days instead of months. Source: https://news.ycombinator.com/item?id=50195488 Tools they used: Claude Code Category: Vibe coding & apps Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
You are helping me set up this AI use case end to end in Grok Bot. Goal: Build a singing app that shows exactly where you're off-key What the original author did: A self-described bad singer got frustrated that his singing app filled up with non-original songs, so he asked Claude Code to build OnKey, which scores pitch against the original recording. His agent researched which audio tools he could use by license and tested them against an eval set. Reported result (as claimed by the author): He says it took about 10 days instead of months. Source: https://news.ycombinator.com/item?id=50195488 Tools they used: Claude Code Category: Vibe coding & apps Please: 1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like). 2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure. 3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data. 4. Finish with a checklist to run it again next time.
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Guides for this use case
How to make a song or album with AI · How to vibe code an app with Claude Code · How to make AI music videos and songs
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