Open, Reproducible Calculation of Assembly Indices

We present assembly-theory, a Rust package for computing assembly indices of covalently bonded molecular structures. This is a key complexity measure of assembly theory, a recent theoretical framework quantifying selection across diverse systems, most importantly chemistry. assembly-theory is designed for researchers and practitioners alike, providing (i) extensible, high-performance implementations of assembly index calculation algorithms, (ii) comprehensive benchmarks against which current and future algorithmic improvements can be tested, and (iii) Python bindings and RDKit-compatible data loaders to support integration with existing computational pipelines.