Can LLMs Engineer Their Own Agent Harness? ByteDance Seed’s HarnessDev Says Only 34 of 64 Changes Generalize
An agent harness is the code round a mannequin: execution loop, instruments, context, state, restoration, and verification. Per the Terminal-Bench 2.1 leaderboard, GPT-5 solves 35.2% of duties inside Terminus 2 however 49.6% inside Codex CLI with similar weights. Most benchmarks preserve that harness fastened. HarnessDev proposed by staff of researchers from ByteDance Seed, Singapore University…
