This is a submission for the Hacktoberfest Open-Source AI Challenge Week 2: Side Hustle
Leapstone is an open-source command-line agent that fixes your code when an API or SDK you depend on ships a breaking change.
When a vendor ships a breaking release, thousands of teams read the same migration guide and make the same mechanical edits by hand. Dependabot bumps the version number, but nothing fixes the code. Leapstone does: it scans your repo for affected call sites, applies exact rewrites, asks a model only for the parts that need judgment, runs your own tests, and opens a reviewable pull request with an honest confidence report.
Who would pay: engineering teams that depend on many fast-moving APIs, and API vendors who want customers to adopt new versions without support tickets. The core is free (Apache-2.0). The paid side, Leapstone Pro, adds pack drafting from changelogs, pack signing, multi-repo batch runs, a team dashboard, and native Claude with managed API-key profiles. It's an open-core side hustle. There are no sales yet.
The idea comes from the "Self-Maintaining APIs" request for startups: API providers shouldn't just announce changes, they should apply them.
Try the whole pipeline offline in about a minute (a scripted stand-in plays the model, so no GPU or key is needed):
git clone https://github.com/Armansiddiqui9/leapstone-core && cd leapstone-core
pip install .
make demo # scan, then a dry-run migration of a sample repo
make test # 97 tests
run is a dry run by default: it prints the diff and a report, and changes nothing in your repo.
Hop to the new version, safely.
Leapstone is an open-source command-line agent that fixes your code when an API or SDK you depend on ships a breaking change. It finds every affected spot, fixes the exact ones with deterministic rewrites, asks an AI model (that you run, on your own machine) only for the parts that need judgment, runs your own tests, and then hands you a reviewable pull request with an honest confidence report.
Status: alpha (v0.3.0). The pipeline is built and tested (97 automated tests). How well real open models perform has not been measured yet. The bundled evaluation uses a scripted stand-in, not an AI. See docs/STATUS.md for exactly what is and is not verified.
When a vendor ships a breaking release, every customer scrambles to update. The vendor writes a migration guide, thousands of teams read it, and thousands of developers make…
revert.patch.--provider hook let extensions add commands and model providers. That's how the paid Pro package plugs in.
Honest status: alpha. The pipeline is tested (97 automated tests), but how well real open models perform has not been measured yet. The bundled evaluation uses a scripted stand-in, not an AI.
Fixing someone's source code means reading it. With a closed API, every team would have to send its private code to a third party, and many companies can't do that. Open-weight models run through Ollama or vLLM keep the code on the developer's machine, so this tool can exist for those teams at all.
Open also means you can swap models as better ones appear, run offline, and audit the safety rules (strict edits, secret redaction, new-branch-only PRs) instead of trusting a black box. And because Migration Packs are plain YAML files with free signature verification, anyone can contribute a pack for the API they know best.