# From Typer

URL: /milo-cli/docs/get-started/migrate-existing-cli/from-typer/
Section: migrate-existing-cli
Tags: migration, typer, cli, mcp

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Typer and Milo both make Python type hints central to CLI authoring. The main migration question is not syntax; it is contract surface. Milo adds MCP tools/list, MCP tools/call, llms.txt discovery, structured error data, and milo verify to the same typed function. Official references: Typer first steps and Typer command arguments. Before import typer app = typer.Typer() @app.command() def greet(name: str, loud: bool = False): message = f"Hello, {name}!" print(message.upper() if loud else message) if __name__ == "__main__": app() After from milo import CLI cli = CLI(name="greeter", description="Greeting commands") @cli.command("greet", description="Return a greeting") def greet(name: str, loud: bool = False) -> str: """Greet someone. Args: name: Person to greet. loud: If true, SHOUT. """ message = f"Hello, {name}!" return message.upper() if loud else message if __name__ == "__main__": cli.run() Mapping Typer concept Milo equivalent typer.run(main) cli = CLI(...); @cli.command(...); cli.run() app = typer.Typer() cli = CLI(...) @app.command() @cli.command("name", description="...") Required argument from name: str Required schema field from name: str Option from flag: bool = False Optional flag from flag: bool = False Function docstring help Function docstring plus Args: parameter descriptions Add The Agent Contract After migrating a Typer command, add these checks: uv run python app.py --llms-txt uv run milo verify app.py uv run pytest tests/ -q And test MCP dispatch directly: from milo.mcp import _call_tool def test_mcp_dispatch(): result = _call_tool(cli, {"name": "greet", "arguments": {"name": "Agent"}}) assert result["content"][0]["text"] == "Hello, Agent!" What To Watch Replace output-first handlers with return values when agents need structured data. Document every public parameter. milo verify warns when schema fields lack descriptions. Keep interactive behavior behind ctx.is_interactive so MCP calls remain deterministic.

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- Author: lbliii
- Word Count: 269
- Reading Time: 1 minutes