I Built RepoGeist: An Open-Source AI That Uncovers the Ghosts in Your Git History
This is a submission for the Hacktoberfest Open-Source AI Challenge Week 4: Ghost in the Machine . There is code in your repository that nobody can see anymore. It had a filename. Someone spent an afternoon writing it. Another developer changed it three weeks later. Then one commit removed it, the
Hacktoberfest Open-Source AI Challenge: Ghost in the Machine Submission 👻🌼
This is a submission for the Hacktoberfest Open-Source AI Challenge Week 4: Ghost in the Machine.
There is code in your repository that nobody can see anymore.
It had a filename. Someone spent an afternoon writing it. Another developer changed it three weeks later. Then one commit removed it, the branch moved on, and the reason slowly disappeared from the team's memory.
Git remembers the code. It does not explain the story.
RepoGeist is a privacy-first Git archaeology application that reconstructs a repository's past and lets you investigate it with a local open-weight AI model.
The deterministic half reads real Git objects. It counts commits and contributors, traces file activity, identifies quiet branches, finds files deleted from the analyzed HEAD, and retrieves their last historical versions without modifying the working tree.
The generative half turns selected evidence into explanations. Ghost Chat answers questions about the repository. Commit Autopsy interprets a bounded diff. The Repository Speaks transforms factual milestones into a haunted chronicle, technical documentary, or developer retrospective. Answers include references to the commits and files supplied as evidence.
My interpretation of “Ghost in the Machine” is both literal and practical: the ghosts are deleted modules, abandoned experiments, and decisions whose authors are no longer in the room.
The most revealing route through RepoGeist's synthetic demo repository is:
That last constraint matters. A confident ghost that invents history is just a hallucination wearing a costume.
Every repository has a past. Some commits still haunt it.
RepoGeist is a privacy-first Git archaeology platform. It reconstructs real repository history, finds code absent from HEAD, surfaces quiet branches, retrieves historical source, and lets a local open-weight model explain the evidence without sending source code to a third party.
Built for the Hacktoberfest 2026 Open-Source AI Challenge — Week 4, Ghost in the Machine.