mcp-gui-tester 0.2.0

Lightweight PyQt6 GUI tester for MCP servers over Streamable HTTP: list tools, fill parameters from each inputSchema, call tools, and inspect results.

mcp-gui-tester

A lightweight PyQt6 GUI tester for MCP servers speaking the Model Context Protocol Streamable HTTP transport (JSON-RPC over POST).

Connect to a running server, browse its tools, fill in parameters through a form generated from each tool's inputSchema, call the tool, and inspect the result — no Node toolchain, no browser, just pip install.

Developed alongside the MoleditPy MCP Server plugin, but fully generic: it works with any MCP server exposing tools over Streamable HTTP.

Installation

pip install mcp-gui-tester

Usage

mcp-gui-tester                                  # defaults to http://127.0.0.1:7891/mcp
mcp-gui-tester --url http://localhost:9000/mcp  # any MCP HTTP endpoint
python -m mcp_gui_tester                        # equivalent

1. Adjust Host / Port / Path if needed and click Connect — the status bar shows the server name, version, and tool count.
2. Select a tool from the filterable list.
3. Fill in the parameters and click Call Tool.
4. Inspect the formatted Result tab or the Raw JSON tab.

Features

• Tool browser — lists every tool from tools/list with its description; filter by name or description text
• Schema-driven parameter forms, generated from each tool's inputSchema:
  • strings → line edit (multi-line editor for code / file-content / XYZ / MOL block parameters)
  • integer / number → spinbox, boolean → checkbox
  • array / object → JSON editor, validated before sending
  • enum → dropdown, default values pre-filled
  • optional parameters carry a send checkbox and are omitted unless checked; required parameters are marked with *
• Result view — formatted text (tool errors flagged with [TOOL ERROR]) plus the raw JSON-RPC response
• Responsive — calls run on a background thread, so slow tools never freeze the GUI

Scope

This is deliberately a small tool. It supports the Streamable HTTP transport and the tools/* capability (initialize, tools/list, tools/call). It does not currently speak stdio transport, SSE streaming, authentication, or the resources/prompts capabilities. For a full-featured inspector, see the official MCP Inspector.

Requirements

• Python 3.9+
• PyQt6 (installed automatically)

License

GPL-3.0-only — see LICENSE.