MCP Liveness

Makes one handshake with an MCP server's endpoint — `server/discover` at protocol revision 2026-07-28, then `initialize` for a server on the older revision — with no credential, and reports what a stock client gets. The server is named either by its exact official-registry `name`, or by its endpoint `url` when it is not in the registry or is listed under another name; exactly one of the two is acc

Returns the six outcomes this server can report — usable, needs_credential, charged, unreachable, local_only and not_listed — what each means for an agent choosing a server from the registry, and the usual next move for each. A static reference: it makes no network request and its answer never changes between calls.

Given a server's exact name in the official MCP registry, reports which of its tools were added, removed, or had their description, input schema or output schema change between a named month and the latest monthly snapshot. Useful when a server that worked before behaves differently now, when a prompt or an integration written against its tools has started failing, or before relying on a cached t

Walks a remote MCP server's OAuth sign-in chain from outside, with no credential and no client registration, and returns the first step that breaks, whose it is (`server`, `identity_provider`, or `client` for a known client bug, with its issue URL), the fix, and the spec section that requires it. Steps, in order: one unauthenticated request (it must answer 401 with a WWW-Authenticate challenge);

Checks a remote MCP server's MCP Apps UI (SEP-1865 `ui://` resources) from outside, with no credential and without calling any tool, and returns the first step that stops the view rendering, whose it is (`server`, or `host` for a known host bug with its issue URL), the fix, and the source (the spec, or the host's published page, with the date read). It opens the server as an MCP Apps host would,