PMCoder resolves 25 more SWE-bench Verified cases

PMCoder resolved 25 more SWE-bench Verified cases by refusing to trust its own "finished" claim, per a study posted to arXiv. That's a 5.0-percentage-point gain over a harness-matched baseline, and it holds across three different backends: Claude Haiku 4.5, DeepSeek-V4-Flash, and an OpenHands port. For teams building coding agents, the backend matters less than whether the harness checks its own work.

The system couples two things agent harnesses usually keep separate: planning and episodic memory. The plan phase now conditions what gets pulled from memory. Memory-derived trajectory stats decide when the agent's stuck and needs a new plan, instead of letting it grind on a broken approach.

The bigger break from convention is verification. PMCoder doesn't accept an agent's self-report that a bug is fixed. It checks whether the reported issue actually reproduces, or stops reproducing, after the patch. On the smaller Verified-500 subset, the gain held at 2.8 percentage points or better across all three backends, per the paper. It doesn't say what the added memory and replanning loop costs in tokens or latency.