mcpx — The MCP Explorer CLI

Explore, test, and debug MCP servers from your terminal. Zero friction.

mcpx is a fast, keyboard-driven CLI tool for developers building and testing Model Context Protocol servers. No GUI needed — just your terminal.

npx mcpx ./my-server.js

Why mcpx?

The MCP ecosystem is exploding, but developer tooling hasn't kept up:

• The official Inspector is a heavyweight web UI
• MCP Explorer is a GUI desktop app
• Neither is fast enough for developers who live in the terminal

mcpx gives you instant server exploration, tool execution, health checks, and benchmarks — all from the command line.

Install

# Use instantly with npx (no install needed)
npx mcpx ./my-server.js

# Or install globally
npm install -g mcpx

Usage

Interactive Explorer (default)

Launch the interactive TUI to browse tools, resources, and prompts:

mcpx ./my-server.js
mcpx npx @modelcontextprotocol/server-filesystem /tmp
mcpx --sse http://localhost:3000/mcp

Navigate with j/k, press Enter to select a tool, type JSON args, and execute. Esc to go back, q to quit.

List Tools, Resources & Prompts

mcpx list tools ./my-server.js
mcpx list resources ./my-server.js
mcpx list prompts ./my-server.js
mcpx list all ./my-server.js

# JSON output for scripting
mcpx list tools --json ./my-server.js | jq '.[].name'

Call a Tool

mcpx call myTool '{"key": "value"}' ./my-server.js
mcpx call list_allowed_directories '{}' npx @modelcontextprotocol/server-filesystem /tmp

# JSON output
mcpx call myTool '{}' --json ./my-server.js

Health Check

Validate that a server initializes correctly, lists capabilities, and has valid schemas:

mcpx test ./my-server.js
mcpx test npx @modelcontextprotocol/server-filesystem /tmp

Returns non-zero exit code on failure — perfect for CI.

Benchmark

Measure server latency for listTools, listResources, listPrompts, and tool calls:

mcpx bench ./my-server.js
mcpx bench -n 50 ./my-server.js   # 50 iterations

Output includes min, max, avg, and p95 latency.

Auto-discover from Config

Load MCP servers directly from your Claude Desktop config:

# List all configured servers
mcpx --config

# Connect to a named server
mcpx --config --server filesystem list tools
mcpx --config --server filesystem

# Use a custom config path
mcpx --config ~/my-config.json --server myserver test

Transport Support

| Transport | Flag | Example | |-----------|------|---------| | stdio (default) | — | mcpx ./server.js | | SSE | --sse | mcpx --sse http://localhost:3000/sse | | Streamable HTTP | --http | mcpx --http http://localhost:3000/mcp |

Examples

# Explore the official filesystem server
mcpx npx @modelcontextprotocol/server-filesystem /tmp

# List all tools from a local server
mcpx list tools node my-server.js

# Call a tool and pipe results
mcpx call search_files '{"path": "/tmp", "pattern": "*.txt"}' --json \
  npx @modelcontextprotocol/server-filesystem /tmp | jq '.result'

# CI health check
mcpx test ./my-server.js || echo "Server unhealthy!"

# Benchmark before deploying
mcpx bench ./my-server.js -n 100

License

MIT