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Collaborator or Assistant? How AI Coding Agents Partition Work Across Pull Request Lifecycles

AI Coding AgentsPull Request WorkflowsCode ReviewSoftware GovernanceHuman AI Interaction

This paper studies 29,585 GitHub pull requests involving OpenAI, Copilot, Devin, Cursor, and Claude Code to measure who starts AI-agent PR work and who merges it. It finds that agents often initiate work in some tools, but humans almost always retain merge authority.

  • Teams need to know where human oversight belongs when AI coding agents create branches, write code, and submit PRs.
  • Prior studies report merge rates, review counts, or productivity, but they do not reconstruct who initiated, reviewed, revised, and merged each PR.
  • This matters because agent-led coding can look autonomous while the merge decision remains human-controlled or recorded only as an automation event.
  • The authors analyze the AIDev dataset: 33,600 raw PRs and 29,585 PRs after excluding 15 without commits and 4,000 without terminal outcomes.
  • They classify each actor as Agent or Human using GitHub actor.type plus login patterns such as bot, copilot, devin, cursor, codex, openai, and claude; validation reports 0.36% residual error.
  • Each PR is mapped through phases: created, review, revision, merged and closed, or unmerged and closed.
  • The core mechanism is simple: identify who made the first commit, identify who executed the merge if one occurred, then assign the PR to one of six Initiator × Approver scenarios.
  • They compute per-tool transition probabilities and median times, then compare tool-scenario association with a chi-square test and Cramér's V.
  • Tool identity predicts the interaction pattern: chi-square = 29,817, df = 20, p < 0.001; Cramér's V = 0.50.
  • Cursor, Devin, and Copilot fall on the Collaborator side, with at least 96% agent-initiated PRs; OpenAI and Claude fall on the Assistant side, with at least 95.6% human-initiated PRs.
  • Merge authority stays human: Agent-Init + Agent-Approved PRs total 14 and stay below 0.1% per tool.
  • Review routing differs by tool: Copilot routes 90.3% of PRs through review, Cursor 51.3%, Devin 52.2%, while OpenAI resolves 76.5% directly and Claude 37.6% directly.
  • Revision loops are more common for Collaborator tools: Revision-to-Review return rates are 95.5% for Copilot and 72.3% for Devin; median review time is 3.0 h for Copilot, 2.0 h for Devin, and 0.7 h for OpenAI.
  • Closure timing varies: median time to unmerged close is 67.8 h for Devin, 0.2 h for Copilot, and 1.4 h for OpenAI.