click-to-mcp

Auto-wrap any Click/typer CLI as an MCP (Model Context Protocol) server.

⭐ Star this repo if you build CLI tools — it helps other devs discover click-to-mcp!

Part of the Revenue Holdings developer tool ecosystem.

Why click-to-mcp?

The problem: You have Python CLIs built with Click or typer. Your AI coding agent (Claude Code, Codex, Cursor) needs to call them — but MCP servers require writing boilerplate from scratch.

The old way:

1. Create a new Python package for your MCP server
2. Define JSON Schema for every tool manually
3. Wire up stdio/HTTP transport
4. Keep it in sync when your CLI changes

The click-to-mcp way:

pip install click-to-mcp
click-to-mcp serve your-cli

One command. Your CLI is now an MCP server. No boilerplate, no schema writing, no maintenance burden.

Real example: api-contract-guardian has 6 commands with 20+ options. Writing an MCP server for it would take 200+ lines of boilerplate. With click-to-mcp: click-to-mcp serve api-contract-guardian — done.

Works with Revenue Holdings CLI tools out of the box — wrap api-contract-guardian, json2sql, deploydiff, or configdrift as MCP servers with zero code changes.

Quick Start

Install from PyPI (recommended):

pip install click-to-mcp

For HTTP+SSE transport (web-based MCP clients), install with the http extra:

pip install "click-to-mcp[http]"

Install directly from GitHub (latest development version):

pip install git+https://github.com/Coding-Dev-Tools/click-to-mcp.git

Or install via Homebrew (macOS/Linux):

brew tap Coding-Dev-Tools/tap
brew install click-to-mcp

Or install via Scoop (Windows):

scoop bucket add Coding-Dev-Tools https://github.com/Coding-Dev-Tools/scoop-bucket
scoop install click-to-mcp

# Discover all Click/typer CLIs installed in your environment
click-to-mcp discover

# List the MCP tools that would be exposed from a CLI (without starting a server)
click-to-mcp list-tools api-contract-guardian
click-to-mcp list-tools --all --json-output   # all CLIs, JSON for CI

# Serve a specific CLI as an MCP server (stdio transport)
click-to-mcp serve api-contract-guardian

# Serve over HTTP+SSE (for web-based MCP clients)
click-to-mcp serve-http api-contract-guardian --port 8000

# Or serve the built-in demo
click-to-mcp demo            # stdio
click-to-mcp demo-http       # HTTP+SSE on port 8000

# Generate MCP client configuration (copy-paste ready JSON)
click-to-mcp config api-contract-guardian
click-to-mcp config api-contract-guardian --client cursor
click-to-mcp config api-contract-guardian --transport http --port 9000
click-to-mcp config --all --client vscode

Then configure your MCP client to connect via stdio or HTTP.

How It Works

click-to-mcp introspects your Click/typer CLI at runtime and maps every command to an MCP tool:

Click Concept	MCP Mapping
@click.command()	MCP tool
@click.argument()	Required input property
@click.option()	Optional input property with default
click.Choice	JSON Schema enum
click.INT/FLOAT	JSON Schema integer/number
click.BOOL / is_flag	JSON Schema boolean
Nested click.Group	Prefixed tools (e.g. config_show)

No annotations, no decorators, no boilerplate. Your existing Click CLI is the MCP server.

MCP Workflow with AI Coding Agents

This section shows how to integrate click-to-mcp with popular AI coding tools so your CLIs become first-class tools that AI agents can invoke directly.

Claude Code

Add your CLI as an MCP server in your project's .claude/settings.json:

{
  "mcpServers": {
    "api-contract-guardian": {
      "command": "click-to-mcp",
      "args": ["serve", "api-contract-guardian"]
    },
    "json2sql": {
      "command": "click-to-mcp",
      "args": ["serve", "json2sql"]
    },
    "deploydiff": {
      "command": "click-to-mcp",
      "args": ["serve", "deploydiff"]
    }
  }
}

Now when you ask Claude Code to "validate my API contracts", it will automatically call the acg_validate MCP tool with the right arguments — no manual command-line invocation needed.

Cursor

Add to your Cursor MCP settings (.cursor/mcp.json):

{
  "mcpServers": {
    "api-contract-guardian": {
      "command": "click-to-mcp",
      "args": ["serve", "api-contract-guardian"]
    }
  }
}

Cline / VS Code

Add to .vscode/mcp.json:

{
  "servers": {
    "api-contract-guardian": {
      "command": "click-to-mcp",
      "args": ["serve", "api-contract-guardian"]
    }
  }
}

Custom Integration (Programmatic)

For CLIs that aren't installed as entry points, use the library API:

# my_mcp_server.py
from click_to_mcp import run
from my_cli import app  # Your Click/typer CLI

run(app, prefix="my-cli", name="my-cli-mcp")

Then reference the script directly:

{
  "mcpServers": {
    "my-cli": {
      "command": "python",
      "args": ["my_mcp_server.py"]
    }
  }
}

What the Agent Sees

When your MCP server is configured, the AI agent sees your CLI commands as native tools. For example, with api-contract-guardian:

Agent: "I need to validate the API contract against the staging server."
→ Calls MCP tool: acg_validate
  Arguments: { "spec_file": "openapi.yaml", "base_url": "https://staging.api.com", "strict": true, "output_format": "json" }
← Result: "Validating openapi.yaml against https://staging.api.com...\n✓ All contracts pass"

The agent doesn't need to know shell syntax, argument flags, or command names. It just calls the tool with structured arguments, and click-to-mcp handles the rest.

Examples

Quick Start (3 lines)

import click
from click_to_mcp import run

@click.group()
def my_cli():
    """My awesome CLI tool."""
    pass

@my_cli.command()
@click.argument("name")
@click.option("--loud", is_flag=True, help="Shout the greeting")
def hello(name: str, loud: bool):
    """Say hello to someone."""
    msg = f"Hello, {name}!"
    if loud:
        msg = msg.upper()
    click.echo(msg)

if __name__ == "__main__":
    run(my_cli, prefix="my-cli", name="my-cli-mcp")

See examples/quick_start.py for the full runnable example.

Wrapping api-contract-guardian

See examples/api_contract_guardian_mcp.py for a demo showing how to wrap API Contract Guardian as an MCP server with validate, extract, and monitor commands.

Usage

CLI — Discover and Serve

# List all installed Click/typer CLIs
click-to-mcp discover

# Serve a specific CLI as an MCP server over stdio
click-to-mcp serve <name>

# Serve over HTTP+SSE (requires pip install "click-to-mcp[http]")
click-to-mcp serve-http <name> --port 8000

# Serve the built-in demo
click-to-mcp demo            # stdio
click-to-mcp demo-http       # HTTP+SSE

# Version info
click-to-mcp --version

Library — Integrate directly

# my_cli.py
import click
from click_to_mcp import serve_stdio

@click.group()
def cli():
    """My CLI tool."""
    pass

@cli.command()
@click.argument("file")
@click.option("--verbose", is_flag=True)
def validate(file: str, verbose: bool) -> None:
    """Validate a file."""
    click.echo(f"Validating {file}...")

# Run as MCP server
serve_stdio(cli, name="my-cli", description="My CLI as MCP server")

Library — High-level run() API

from click_to_mcp import run
from my_cli import app

# Automatically detects Click/typer instances
run(app, prefix="my-cli")

Features

• Auto-discovery: click-to-mcp discover scans console_scripts entry points for Click/typer CLIs
• Tool preview: click-to-mcp list-tools <name> shows MCP tools without starting a server (CI-friendly with --json-output)
• Client config: click-to-mcp config <name> generates ready-to-paste JSON for Claude Desktop, Cursor, VS Code, Windsurf, and Cline
• Serve any CLI: click-to-mcp serve <name> wraps any discovered CLI as an MCP server
• HTTP+SSE transport: click-to-mcp serve-http <name> serves over HTTP for web-based clients (v0.3.0+)
• Supports both Click and Typer: Full compatibility with both frameworks
• Nested command groups: Handles subcommand groups recursively with prefixed tool names
• Parameter introspection: Correctly maps Click options, arguments, types, enums, defaults, and help text to JSON Schema
• Full MCP protocol: Implements initialize, tools/list, tools/call over stdio and HTTP+SSE
• Health endpoint: HTTP servers expose /health for monitoring and load balancers

Transports

Stdio (default)

Best for local CLI-based MCP clients (Claude Code, Cursor, Cline). No extra dependencies needed.

click-to-mcp serve <name>

HTTP+SSE (v0.3.0+)

Best for web-based MCP clients, remote access, and multi-user setups. Requires the [http] extra.

# Install HTTP dependencies
pip install "click-to-mcp[http]"

# Start an HTTP+SSE server
click-to-mcp serve-http <name> --host 127.0.0.1 --port 8000

Endpoints:

Endpoint	Method	Description
/sse	GET	SSE stream (server-to-client events)
/messages	POST	JSON-RPC message endpoint
/health	GET	Health check (JSON status)

Configure your MCP client with the SSE URL:

{
  "mcpServers": {
    "my-cli": {
      "url": "http://127.0.0.1:8000/sse"
    }
  }
}

MCP Protocol

Click-to-MCP implements the standard MCP protocol with:

• initialize — protocol handshake (returns server capabilities)
• tools/list — discover all CLI commands as MCP tools with JSON Schema inputs
• tools/call — invoke a CLI command with typed arguments

Integration with Existing CLIs

Add an MCP server entry point to any Click/typer CLI:

# cli.py — add a subcommand to run as MCP server
import typer
from click_to_mcp import run

app = typer.Typer(...)

@app.command()
def mcp():
    """Run as an MCP server over stdio."""
    from click_to_mcp import run
    run(app)

Then agents can use it as: your-cli mcp

Development

git clone https://github.com/Coding-Dev-Tools/click-to-mcp
cd click-to-mcp
pip install -e ".[dev,http]"
python -m pytest tests/ -v          # 23 tests (12 stdio + 11 HTTP)
click-to-mcp demo                    # starts MCP stdio server for demo CLI
click-to-mcp demo-http               # starts MCP HTTP+SSE server on port 8000

Pricing

click-to-mcp is free and open source under Apache 2.0. No license key required, no rate limits, no telemetry.

It also works with any Revenue Holdings CLI tool — even on the free tier.

License

Apache 2.0

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_{Part of Revenue Holdings — developer CLI tools built by autonomous AI agents.}