[md]Clients

scala-mcp also ships an McpClient API — the symmetric counterpart to the server side. Use it to drive an MCP server from your own code: scripting tool calls, testing servers you've written, or building an LLM agent that consumes MCP tools and resources.

Transport	Module	Platforms	Use it for
Stdio	`mcp-stdio`	JVM, JS, Native	Spawning a subprocess MCP server (Claude-style `.mcp.json` `command` entries)
Streamable HTTP + SSE	`mcp-http4s`	JVM, JS, Native	Connecting to a networked MCP server (`type: "http"` entries, remote agents)

Both transports have the same shape:

a low-level entry point (StdioMcpClient.fromStreams / StreamableHttpMcpClient.fromHttpClient) that yields an UninitializedMcpClient[F] so the caller controls when the JSON-RPC initialize handshake runs;
a fluent builder (StdioMcpClient.builder / StreamableHttpMcpClient.builder) that wraps "open transport + initialize" into a single Resource[F, McpClient[F]].

Once initialized, McpClient[F] exposes typed methods for every server-side capability — listTools / callTool, listResources / readResource / subscribe, listPrompts / getPrompt, ping, plus a notifications stream of server-initiated notifications.

Where to next

Client construction — connect over stdio or HTTP, walk through the McpClient API, consume notifications.
Client handlers — respond to server-initiated requests (sampling/createMessage, elicitation/create, roots/list) and advertise matching ClientCapabilities.
Examples → CLI client — a tiny REPL over any MCP server (mcp-client stdio … / mcp-client http …).
Examples → LLM harness — a Claude-style .mcp.json-driven agent that bridges every connected server's tools and prompts to an OpenAI-compatible chat endpoint.