Pasteur

Louis is an MCP server + Slack bot that turns a genome-scale CD4⁺ T-cell CRISPRi Perturb-seq screen (Marson/Pritchard 2025) into a discovery-and-memory assistant living inside Claude — no separate app, no API key. Named for Pasteur, it discovers understudied, druggable regulator handles wired to a disease's own GWAS risk genes, gated by CRISPRi knockdown QC and activation state; run blind as a positive control, the same ranking re-derives the Th17 masters STAT3/BATF/IRF4 — 1 of 77 regulator clusters clears significance (Crohn's q=0.025): disease-calibrated, not a hub. Its sharpest move is honesty. Handed its own flagship RA lead DOT1L, Louis stress-tests it A→C — the wiring is a cross-disease artifact, and because DOT1L props up regulatory T cells an inhibitor likely worsens RA — then returns the survivor, HDAC7 for Th17-driven colitis (favorable, peer-reviewed direction), with the go/no-go experiment. It weighs every source by provenance (a preprint is never decisive), reviews itself, and the whole lab writes back to a shared memory. Why it matters: the bottleneck a bench scientist named isn't analysis — it's trust. A discovery tool that kills its own darling, with receipts, is one you can hand the survivors.