Alibaba-led preprint: the best of ten coding agents fully finishes 26.4% of real user requests
Researchers from Alibaba and several universities, in an arXiv preprint submitted on 26 October 2026, report that OpenAI's GPT-6 Astra met 69.9% of acceptance criteria per task on average but fully satisfied only 26.4% of 273 tasks. The Decoder covered the paper on 8 November. The tasks come from real coding sessions, and the authors favoured requests where users had to rephrase or roll back changes.
Why it matters: A pull request that covers most of a ticket looks like progress and lands as work for the reviewer. The paper says 73.6% of the leader's tasks keep at least one unmet criterion. If your pilot reports how much of each ticket the agent covered, it will read better than the review queue feels.
The catch: AI judges did the grading, though two frontend experts checked a sample of scores. The authors chose the ten models, the work is not peer reviewed, and Alibaba, the lead affiliation, also makes the Qwen models in the test. Every model ran in one harness, Claude Code, capped at three hours and 120 turns. Each task is one fixed request, so follow-up questions are not tested.
Zoom out: The harness mattered as much as the model. Swapping only the harness moved Qwen3.8-27B's repository-edit score from 0.560 to 0.749, and the order of two models changed with it. The authors say leaderboards should name model and harness together.
What to do: Track the share of tickets that merge with no human follow-up commit, as its own metric next to cost per ticket. Split tickets that mix layout, interaction and content changes; the authors report scores fall as a request mixes more change types. When you trial a new model, hold the harness fixed on 20 of your own tickets, then change one thing at a time.
Our coverage →arXiv: Co-Design Bench, authors' preprint ↗The Decoder: AI coding agents still need human cleanup on nearly three out of four tasks ↗