AI coding agents allow software developers to generate code quickly, which raises a practical question for project managers and open source maintainers: can vibe coders with less development experience substitute for expert developers? To explore whether developer experience still matters in AI-assisted development, we study 22,953 Pull Requests (PRs) from 1,719 vibe coders in the GitHub repositories of the AIDev dataset. We split vibe coders into lower experience vibe coders (ExpLow) and higher experience vibe coders (ExpHigh) and compare contribution magnitude and PR acceptance rates across PR categories. We find that ExpLow submits PRs with larger volume (2.15 × more commits and 1.47 × more files changed) than ExpHigh. Moreover, ExpLow PRs, when compared to ExpHigh, receive 4.52 × more review comments, and have 31% lower acceptance rates, and remain open 5.16 × longer before resolution. Our results indicate that low-experienced vibe coders focus on generating more code while shifting verification burden onto reviewers. For practice, project managers may not be able to safely replace experienced developers with low-experience vibe coders without increasing review capacity. Development teams should therefore combine targeted training for novices with adaptive PR review cycles.

Continuous Integration and Deployment (CI/CD) workflows are central to modern software delivery, yet the reliability of agentic AI bots operating within these workflows remain underexplored. Using pull requests (PRs), commits, and repositories from the AIDev dataset, we retrieved associated CI/CD workflow runs via the GitHub Actions API and analyzed 61,837 runs from 2,355 repositories, all triggered by PRs generated by five AI bots: Claude, Devin, Cursor, Copilot, and Codex. We observed substantial agent-dependent differences in workflow reliability, with Copilot and Codex achieving the highest success rates ∼ 93% and ∼ 94% respectively. At the repository level, we find a negative correlation between AI agent contribution frequency and workflow success rate, suggesting that a higher frequency of Agentic PRs may hinder CI/CD workflow reliability. We defined a taxonomy of 13 categories against 3,067 agentic PRs whose associated workflows failed, and observed a trend analysis that indicates visually observable shifts from functional to non-functional PR categories over time, although these trends are not statistically significant. Our findings motivate the need for actionable guidance on integrating AI agents into CI/CD workflows and prioritizing safeguards in workflows where failures are most likely to occur.