Interesting write-up, but I feel like a lot of its argument relies on the interpretation of ECI scores as merely showing linear improvement in AI capabilities. Sure, Epoch AI themselves claim that ECI's scale is linear, meaning that a large increase in capabilities should result in a large increase in ECI. Yet, the widely perceived jump in coding abilities in late 2025 that started making agentic coding actually productive doesn't really show on the software engineering ECI.

The ECI is basically an aggregate of benchmark scores, but benchmark complexity might not increase linearly. In fact, if LLM capabilities grew exponentially, then benchmarks would also need to increase their difficulty / complexity exponentially to stay relevant.