client_helpers_demo

MCP Client Helpers Demo

This example directory explores patterns for creating helper functions to simplify using the Go MCP client (github.com/localrivet/gomcp/client).

Goal

The primary goal is to develop a configuration loading mechanism (LoadServersFromConfig) that allows a client application to connect to multiple MCP servers based on a configuration structure. This loader should:

1. Parse a configuration defining different servers.
2. Support connecting to servers using different methods based on a prefix in the configuration's command field:
   • @sse:<url>: Connect to a running server via Server-Sent Events.
   • @ws:<url>: Connect to a running server via WebSocket.
   • @stdio:<command_string>: (Intended) Launch the specified command as a local process and connect to its standard input/output streams.
3. Return a map of connected *client.Client instances, keyed by the server name from the configuration.

Current State & Iteration

We iterated on the implementation within loader.go:

1. Initial Idea: Support all prefixes, including launching local processes for @stdio: and potentially @docker:.
2. Blocker Identified: Realized that the standard client.NewStdioClient connects to the current application's stdio, not the stdio pipes of an externally launched process. Manually constructing the client.Client struct with pipes failed due to unexported fields.
3. Hypothetical Solution: Proposed needing a new constructor in the core client package (e.g., NewClientFromPipes or NewClientWithTransport) that could accept pre-existing io.Reader/io.WriteCloser pipes. A placeholder function (newClientFromPipes) was added to loader.go to represent this needed functionality.
4. Current Code (Connect-Only Pivot): To proceed without modifying the core client package yet, the code was simplified to only support connection prefixes (@sse:, @ws:). The @stdio: prefix was temporarily redefined to use client.NewStdioClient (connecting to the app's stdio), and process launching logic (@docker:, default case, exec.Cmd handling, ManagedClient, TerminateManagedClients) was removed.

Therefore, the current code in loader.go does NOT implement the intended functionality for @stdio:<command_string> (launching the command). It only handles connections via @sse:, @ws:, and the application's own @stdio:.

Next Steps

• Review the current LoadServersFromConfig implementation which focuses on connections.
• Decide whether to pursue adding the necessary constructor (like NewClientFromPipes) to the core client package to enable launching and connecting to stdio-based subprocesses as originally intended for @stdio:<command_string>.
• Explore other client helper patterns (e.g., simplified tool calling).