Noodle: Semantic Biomedical Literature Discovery and Navigable Publication Graph

Noodle is a free, public, read-only web application for semantic discovery and navigation of biomedical literature. It integrates publication metadata and source-linked context from PubMed, Europe PMC, and OpenAlex while preserving those services as the authoritative sources. Noodle supports natural-language and identifier-based retrieval, gene, variant, phenotype, and indexed-concept views, and navigable semantic publication neighbourhoods. The production SPECTER2 graph covers 1,684,299 canonical non-retracted works with validated 8–12-work neighbourhoods; the current search-engine-indexable cohort contains 10,000 current, non-retracted, policy-cleared PMID publication pages. Semantic proximity is a discovery signal and does not establish scientific evidence, causality, clinical validity, diagnosis, or treatment guidance. This public technical service description documents the service boundary, provenance, retrieval roles, graph contract, governance, limitations, and citation metadata. The CC BY 4.0 licence applies to this document only, not to third-party publication content or private implementation source code.