API Reference

Classes

BaseMcpServer (abstract)

Abstract base class for an MCP server. Holds registered tools and provides the lifecycle contract.

abstract class BaseMcpServer {
    constructor(serverInfo: ServerInfo);
    register(item: Tool | ToolPackage): void;
    abstract start(): Promise<void>;
    stop(): Promise<void>;
}

constructor(serverInfo)

Creates the underlying McpServer from @modelcontextprotocol/sdk.

Parameter	Type	Description
serverInfo	ServerInfo	{ name: string; version: string }

register(item)

Registers a Tool or all tools in a ToolPackage. Duplicate tool names cause an error from the SDK (not silently overwritten). Must be called before start() — tools are snapshotted at session creation time.

Parameter	Type	Description
item	Tool \| ToolPackage	Single tool or package of tools to register

start() (abstract)

Subclasses implement this to connect the server to a transport.

stop()

Calls the onStop() lifecycle hook then closes the underlying McpServer.

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StdioMcpServer

MCP server over standard input/output. Extends BaseMcpServer.

class StdioMcpServer extends BaseMcpServer {
    constructor(serverInfo: ServerInfo);
    start(): Promise<void>;
}

start()

Creates a StdioServerTransport and connects. Reads JSON-RPC messages from stdin and writes responses to stdout.

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HttpMcpServer

MCP server over Streamable HTTP using Express. Each HTTP client gets its own session. Extends BaseMcpServer.

class HttpMcpServer extends BaseMcpServer {
    constructor(serverInfo: HttpServerInfo);
    start(): Promise<void>;
    stop(): Promise<void>;
}

constructor(serverInfo)

Parameter	Type	Description
serverInfo	HttpServerInfo	{ name: string; version: string; port: number }

start()

Binds Express to the configured port. Idempotent — subsequent calls are no-ops while the server is already listening.

stop()

Closes all active HTTP sessions (each transport is closed), clears the session map, then stops the Express listener.

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Types

ServerInfo

type ServerInfo = {
    name: string;
    version: string;
};

Metadata sent to MCP clients during initialization.

HttpServerInfo

type HttpServerInfo = ServerInfo & {
    port: number;
};

Extends ServerInfo with the TCP port for Express to bind to.