cxg-census-mcp

Gives Claude direct access to the CZ CELLxGENE Discover Census, a single-cell RNA-seq atlas covering millions of cells across hundreds of datasets. The server wraps 13 tools for querying cell counts, filtering by ontology terms (cell types via CL, tissues via UBERON, diseases via MONDO), aggregating gene expression, and exporting subsets. It handles ontology resolution through EBI's OLS4 API and includes tiered execution with cost caps to keep queries feasible. Every response includes dataset provenance and CC BY 4.0 attribution. Useful for exploratory analysis when you need to ask questions like "how does this gene's expression differ between healthy and diseased lung tissue" without writing SOMA queries by hand. Community project, unaffiliated with CZI, alpha stage but functional.