Parsimony Benchmark Tracks How Much Code AI Models Add
An open-source benchmark called Parsimony measures the code AI adds minus the code it deletes when it modifies a program. It analyzes existing benchmark modification data using a unit that counts syntactic elements rather than lines, so line breaks and comments do not count. In its published comparison, Claude Opus 5.5(high) adds about 1.1 times as much code as other models, while GPT-6.1 Sol(high)/Codex adds about 0.7 times.