4 tagged Paper Search, measured the same way as everything else here.
Skill Claude CodeCodex
Search, download, and read academic papers from 20+ sources (arXiv, PubMed, Semantic Scholar, CrossRef, etc). Use when the user asks to find papers, search for research, look up academic literature, download a paper PDF, or extract text from a paper.
LivXue/paper-search-with-citation
Skill Claude CodeCodex
Use when working with the Academic Paper Search and BibTeX Generation API, including searching papers, retrieving BibTeX citations, and monitoring API manager statistics.
Skill Codex
Use NB Paper Search for academic/patent discovery, optional External Search v1 websearch, multi-preset/source union, identifier lookup, durable researchrun history, citationexpand plan/run/resume, checksum-bound transparent assessment, provider-mediated artifact/PDF acquisition and extraction, selected…