“Same mission, bigger stage”: OpenAI hires Git AI founders to help Codex prove its ROI

OpenAI has hired the founders of Git AI, an open-source tool that tracks how much code AI writes and measures the performance and cost of coding agents.

Taking to LinkedIn late Friday night, Aidan Cunniffe noted that he and his Git AI co-founder Sasha Varlamov will join OpenAI’s Codex team, where they will work on giving businesses better data on how coding agents perform and the returns they generate.

“Same mission, bigger stage,” Cunniffe writes.

While details of the integration plans are scant, OpenAI’s Thibault Sottiaux, a member of technical staff at OpenAI who’s working on ChatGPT and Codex, confirmed on X that the company wants to use Git AI’s technology to help businesses understand Codex’s impact.

“We’ll make it easier for businesses to see where Codex is making a difference when working through problems for individuals and teams,” Sottiaux writes.

In a separate blog post announcing the deal on Friday, Cunniffe notes that the tie-up reflects a shared focus on measuring the performance and value of AI coding tools.

“OpenAI shares our belief that users should have the data to compare model performance and understand the ROI of every token they spend.”

“OpenAI shares our belief that users should have the data to compare model performance and understand the ROI of every token they spend,” he writes.

Tracking AI-generated code

Git AI, for the uninitiated, is an open-source Git extension that tracks AI-generated code. Every line of code is linked to the agent, model, and prompts that generated it, preserving the context behind a change even after the code has been committed, merged, or rebased.

More broadly, it’s designed to help teams see how much AI-generated code ultimately reaches production, how often it’s reworked, and where time and tokens are being spent. That data can then be used to compare coding agents and models, and assess whether the money being spent on them is producing useful output.

The tool already supports a broad range of coding agents, including OpenAI Codex, Anthropic’s Claude Code, Cursor, and Google’s Gemini CLI, as well as background agents including Codex Cloud, Claude Web, Cursor Agent, and Devin.

After installation, supported agents automatically report their edits to Git AI. For developers, the pitch is basically: “Just prompt and commit”—they can keep using their coding tools and Git as usual.

Git AI can then show the split between human- and AI-written code and trace individual lines back to the agent that produced them.

The story so far

Cunniffe has, in fact, been here before. He founded developer tooling startup Optic in 2018, which built open-source tools around API development, before Atlassian acquired the company in 2024. He subsequently joined Atlassian as a principal product manager leading go-to-market efforts for developer tools.

Git AI began while Cunniffe was still at Atlassian. He and Varlamov started working on the project in the summer of 2025 as a side project, initially trying to answer one seemingly simple question: how much of their code was actually being written by AI, and what happened to that code afterward?

By the first major release in November, Cunniffe was publicly describing Git AI as a “weekend project” that had grown into something much larger. He subsequently left Atlassian in January 2026 to turn Git AI into a company, building a commercial business around the open-source project.

Now, less than a year later, Cunniffe and Varlamov are heading to OpenAI. It is not yet clear what that means for Git AI as a commercial business, but with both founders joining OpenAI, the standalone business will likely be wound down while the open-source project continues.

The New Stack has reached out to OpenAI and will update this story when we hear back.

Cunniffe, for his part, says OpenAI will continue backing the open-source project.

“We’ll keep investing in open source, while also giving enterprises the data they need to build effective software factories,” he writes.

How that cross-model independence ultimately holds up under OpenAI stewardship will be one of the more interesting things to watch.

Paul is an experienced technology journalist covering some of the biggest stories from Europe and beyond, most recently at TechCrunch where he covered startups, enterprise, Big Tech, infrastructure, open source, AI, regulation, and more. Based in London, these days Paul…

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