MCP REPL

Interactive REPL for testing Model Context Protocol (MCP) servers.

Replated blog post: https://kokosa.dev/blog/2026/repl-mcp/.

Features

• List and inspect tools, prompts, and resources
• Call tools with JSON or interactive parameter input
• Tab autocompletion for commands and tool names
• Command history (arrow keys)
• Rich terminal UI with syntax highlighting

Installation

Option 1: Install from PyPI (Recommended)

# Using uv (fast, Rust-based)
uv tool install repl-mcp

# Using pipx
pipx install repl-mcp

# Using pip
pip install repl-mcp

Option 2: Run directly without installing

# Using uvx
uvx repl-mcp -c "npx mcp-remote https://mcp.atlassian.com/v1/mcp"

Option 3: Development Setup

git clone https://github.com/kkokosa/repl-mcp.git
cd repl-mcp
pip install -e .

Usage

[!NOTE] mcp-remote sidenote - Some MCP servers (like Atlassian) use OAuth for authentication and don't support direct HTTP connections. The mcp-remote MCP bridges this gap by handling OAuth flows locally and/or converting HTTP-based MCP servers to stdio transport. Beware that for OAuth-based servers, mcp-remote needs to receive the OAuth callback. If you're running in an environment without a public URL (like WSL or a remote server), you'll need a tunneling tool like ngrok to expose the callback endpoint.

Stdio Transport (command-based)

# Simple MCP server
repl-mcp -c "npx -y @modelcontextprotocol/server-filesystem /tmp"

# Remote MCP server via mcp-remote proxy (requires ngrok or similar for OAuth authorization!)
repl-mcp -c "npx mcp-remote https://mcp.atlassian.com/v1/mcp"

# Local Python MCP server
repl-mcp -c "python my_mcp_server.py"

# Using uvx
repl-mcp -c "uvx mcp-server-sqlite --db-path test.db"

HTTP Transport (URL-based)

# GitHub Copilot MCP
repl-mcp -url https://api.githubcopilot.com/mcp/ \
         -H "Authorization: Bearer YOUR_GITHUB_TOKEN" \
         -t http

# Notion MCP
repl-mcp -u https://mcp.notion.com/mcp

# Multiple headers
repl-mcp -u https://example.com/mcp \
         -H "Authorization: Bearer TOKEN" \
         -H "X-Custom-Header: value"

Using a config file

# If multiple servers in config, you'll be prompted to choose
repl-mcp --config sample-mcp-config.json

# Or select specific server directly
repl-mcp --config sample-mcp-config.json --server github

Config file formats

Stdio transport:

{
  "command": "npx",
  "args": ["mcp-remote", "https://mcp.atlassian.com/v1/mcp"]
}

HTTP transport:

{
  "url": "https://api.githubcopilot.com/mcp/",
  "headers": {
    "Authorization": "Bearer YOUR_TOKEN"
  }
}

Multiple servers (Cursor/Claude Desktop format):

{
  "mcpServers": {
    "atlassian": {
      "command": "npx",
      "args": ["mcp-remote", "https://mcp.atlassian.com/v1/mcp"]
    },
    "github": {
      "url": "https://api.githubcopilot.com/mcp/",
      "headers": {
        "Authorization": "Bearer YOUR_TOKEN"
      }
    },
    "notion": {
      "url": "https://mcp.notion.com/mcp",
      "headers": {}
    }
  }
}

YAML format:

command: npx
args:
  - mcp-remote
  - https://mcp.atlassian.com/v1/mcp

REPL Commands

Command	Description
tools	List all available tools
tool <name>	Show detailed info about a specific tool
prompts	List all available prompts
resources	List all available resources
call <tool> [args]	Call a tool (interactive input if no args)
prompt <name> [args]	Get a prompt with optional JSON arguments
read <uri>	Read a resource by URI
info	Show server info and capabilities
help	Show help message
quit / exit / q	Exit the REPL

Keyboard Shortcuts

Key	Action
Tab	Autocomplete commands and tool names
↑ / ↓	Navigate command history
Ctrl+C	Cancel current input
Ctrl+D	Exit REPL

Examples

mcp> tools
┌─────────────────────────────────────────────────────────┐
│ Available Tools (15)                                    │
├──────────────────┬───────────────────────────┬──────────┤
│ Name             │ Description               │ Params   │
├──────────────────┼───────────────────────────┼──────────┤
│ get_issue        │ Retrieves a Jira issue... │ issueKey │
│ search_issues    │ Search for issues using...│ jql      │
└──────────────────┴───────────────────────────┴──────────┘

mcp> call get_issue {"issueKey": "PROJ-123"}
┌─────────────────────────────────────────────────────────┐
│ Result                                                  │
├─────────────────────────────────────────────────────────┤
│ {                                                       │
│   "key": "PROJ-123",                                    │
│   "summary": "Example issue",                           │
│   ...                                                   │
│ }                                                       │
└─────────────────────────────────────────────────────────┘

mcp> quit
Goodbye!

Requirements

• Python 3.10+
• Node.js (if using npx mcp-remote)