Coding agents have taken over open-source development.
Yet our understanding of how developers actually use them — what they ask for, what they accept, what they throw away — is still mostly anecdotal.
The biggest bottleneck for open-source agent research is real interaction data.
SWE-chat is that data.
Each session pairs the full agent transcript — prompts, replies, every tool call — with the resulting git history. We can see, line by line, which code the human wrote and which the agent wrote.
of sessions are now ~all agent-written. Doubled in three months.
of agent-produced code survives into commits.
of prompts ask the agent to explain code — the #1 intent, ahead of creating new code.
of turns get pushback or interruption. Agents ask for clarification in just 1.4%.
of vibe-coding users still act as expert nitpickers — meticulously correcting agent output as it comes in.
more security vulnerabilities per 1K lines than human-only code.
Three distinct modes emerge from the data.
Human-only: agent assists, human codes. Collaborative: shared authorship — the most cost-efficient mode. Vibe coding: agent writes nearly everything — ~3× more tokens per committed line.
We ran Semgrep on every commit, before and after.
Vibe-coded commits introduce 9× more vulnerabilities than human-only and 5× more than collaborative.
Vibe coding fixes more vulnerabilities too — but every mode introduces more than it fixes.
New Semgrep findings introduced per 1,000 committed lines, by coding mode.