@zevruna/client

MCP handshake client that captures a server's advertised contract.

Used by the zevruna CLI and by Zevruna's pollers. Connects over streamable HTTP with an SSE fallback, and returns a snapshot ready for @zevruna/diff.

Install

npm i @zevruna/client

Usage

import { takeSnapshot } from "@zevruna/client";

const snapshot = await takeSnapshot("https://mcp.example.com/mcp");
// { server, takenAt, protocolVersion, tools, resources, prompts }

Second argument is optional: { headers, timeoutMs }, headers for an authenticated server.

Local stdio servers are snapshotted by running them:

import { takeStdioSnapshot } from "@zevruna/client/stdio";

const snapshot = await takeStdioSnapshot("npx", ["-y", "some-mcp-server"]);

Schemas only

takeSnapshot performs initialize, tools/list, resources/list and prompts/list. It never calls a tool, so no arguments, payloads or PII are ever read. A server that advertises none of the three is an error; missing any one of them is not.

Hard caps guard against a hostile or broken server, 15s connect, 15s per list, 2000 tools, and are exported as LIMITS.

License

MIT