META-HARNESS: END-TO-END OPTIMIZATION OF MODEL HARNESSES

Summary from the TLDR AI newsletter

The performance of large language model systems depends not just on model weights, but also on their harnesses. Meta-Harness is an outer-loop system that searches over harness code for LLM applications. Its harnesses surpass the best hand-engineered harnesses on agentic coding benchmarks. Meta-Harness shows how richer access to prior experience can enable automated harness engineering.