Developer Creates LoopSleuth To Detect Quadratic Complexity

On 2026-01-31, an engineer on the transformers project fixed a tokenizer conversion bug that reduced a conversion step from four minutes to about one second on very large vocabularies (100k+ tokens). They then built LoopSleuth, a Rust CLI using llama.cpp and local models (e.g., Qwen2.5-Coder 3B Q4) to scan roughly 3,000 Python functions and flag about 20 quadratic-pattern instances as linter-like warnings.