Molecular Graph Assembly - scaffold/site/fragment combinatorial core (no AI)

What it is

Structural core of the research-grade molecular-design engine: the shared atom-bond graph { atoms, bonds, charges?, sites? }, the additive FragmentProps descriptor, and the exact mixed-radix index<->state<->explicit-graph mapping over a fixed scaffold with N attachment sites. Deterministic and exact (integer odometer, append-only assembly so scaffold indices are stable). This is a LIBRARY brick composed by the provable sampler plugin; it computes no property and makes NO chemical claim - the substrate carries no chemical advantage (mesh57/HVP benchmarked information-equivalent to Weisfeiler-Leman). The value is a provably-correct, reproducible sampler substrate.

Honest scope

Authorities cited

• Mixed-radix odometer indexing (big-endian) matches geometric_graph_sampler.indexOf/stateOf convention.
• Half-bond integer valence units reuse mol_graph_validity.plugin.es (Greenwood & Earnshaw standard valences).
• Additive fragment descriptors: Hansch & Leo 1979 (logP pi-additivity); Ertl et al. J.Med.Chem. 2000 (TPSA); Lipinski 2001 (HBD/HBA); Veber 2002 (rotatable bonds).