Side-by-side comparison of two Model Context Protocol servers — install paths, tools, quality signals, and directory engagement so you can pick the right one for Claude, Cursor, and other MCP clients.
Chemistry toolbox computed from authoritative data: molecular weight / molar mass of any formula (nested groups, isotope labels, propagated NIST uncertainties, percent composition), isotope-distribution mass spectra (m/z peaks for a given charge), and name⇆formula lookup with isomer resolution. Element masses from the NIST Atomic Weights and Isotopic Compositions database; offline and deterministic, with an optional on-by-default online fallback (PubChem/Wikidata/EPA CompTox) that can be disabled. uvx mcp-molecules.
Access legislative data from all 50 US states and Congress — search bills, get full text, track votes, and look up legislators via the LegiScan API.