Cito

Cito is a hybrid search engine over the Semantic Scholar corpus: 236M papers in the keyword index, 146M with SPECTER2 dense vectors, fused with RRF and reranked by a cross-encoder. Free web search with no signup, a plain JSON API, and a native MCP endpoint so agents like Claude Code can run deep literature research without upstream rate limits. Built because every academic API throttled my agents to death.