[Feature] MCP Server Discovery for Testing MCP-Compatible APIs

[Aldric-Core]

Feature Request

Description

Add support for discovering and testing MCP (Model Context Protocol) server endpoints. As MCP becomes the standard for AI agent tool access, developers need ways to test MCP servers just like they test REST APIs.

Proposed Feature

HTTPie could support:

1. http mcp://server-name/tool-name syntax for calling MCP tools
2. Auto-discovery of available tools from MCP servers
3. JSON-RPC formatting for MCP requests

Example

Testing an MCP server like ToolPipe (238+ developer tools):

# Current: manual JSON-RPC
http POST https://toolpipe.dev/mcp jsonrpc=2.0 method=tools/call params:='{"name":"json_format","arguments":{"json":"{\"a\":1}"}}'

# Proposed: native MCP support  
http mcp toolpipe json_format json='{"a":1}'

Why

MCP has 8M+ npm downloads. As more services expose MCP interfaces, developers need proper testing tools.