{"@context":"https://schema.org","@type":"Dataset","name":"MCP Registry Runtime Liveness Census","description":"Independent runtime liveness census of the official Model Context Protocol registry population. On 2026-06-10, of 1481 probed registry servers (out of 4915 with a remote endpoint), 523 answered an anonymous MCP initialize handshake, 518 were alive but auth-gated, and 82 were unreachable.","url":"https://dominionobservatory.com/atlas/census","creator":{"@type":"Organization","name":"Dominion Observatory","url":"https://dominionobservatory.com"},"isAccessibleForFree":true,"dateModified":"2026-06-10","measurementTechnique":"Anonymous MCP `initialize` JSON-RPC handshake over each registry-listed remote endpoint; responses categorized without conflating auth-gated (401/403) with dead.","variableMeasured":[{"@type":"PropertyValue","name":"registry_servers_total","value":11557},{"@type":"PropertyValue","name":"with_remote_endpoint","value":4915},{"@type":"PropertyValue","name":"probed","value":1481},{"@type":"PropertyValue","name":"handshake_ok","value":523},{"@type":"PropertyValue","name":"auth_gated","value":518},{"@type":"PropertyValue","name":"unreachable","value":82}],"provenance":{"row_hash":"9c2f19026409949cab3fa858b16e697ec06babe5b6e1c31b28cb6df73a54656c","prev_hash":"GENESIS","hash_alg":"SHA-256","note":"Hash-chained across runs for tamper-evidence."}}