From Cobra - Milo

Cobra is a Go CLI framework built around command structs, generated files, and flag binding. Milo is a Python framework built around typed functions. Migrating from Cobra is usually a rewrite of command handlers, not a mechanical port.

Official references: Cobra getting started and Cobra flags guide.

Command Trees

Cobra command trees map cleanly to Milo groups:

from milo import CLI

cli = CLI(name="cloud", description="Cloud operations")
cluster = cli.group("cluster", description="Cluster commands")
node = cluster.group("node", description="Node commands")


@node.command("drain", description="Drain a node")
def drain(name: str, force: bool = False) -> dict[str, str | bool]:
    """Drain a node.

    Args:
        name: Node name.
        force: Skip confirmation checks.
    """
    return {"name": name, "force": force, "status": "draining"}

Surface	Name
CLI	`cloud cluster node drain --name node-1 --force`
Programmatic	`cli.call("cluster.node.drain", name="node-1", force=True)`
MCP	`{"name": "cluster.node.drain", "arguments": {"name": "node-1", "force": true}}`

Mapping

Cobra concept	Milo equivalent
Root command	`CLI(name=..., description=...)`
Subcommand	`cli.group(...)` or `@group.command(...)`
Local flag	Function parameter with a default
Required flag	Function parameter without a default
Persistent flag	`Context`, config loading, or explicit parameter passed to each command
`RunE`returning error	Raise`MiloError`or another exception; MCP receives structured tool errors
Generated command file	Plain Python module with typed command functions

What To Watch

Cobra's persistent flags are convenient but can hide command contracts. In Milo, prefer explicit parameters when agents need to see the value in schema.
If a Cobra command relies on global mutable state, move that state to config, injected context, or an explicit boundary before making MCP calls concurrent.
Preserve command names and aliases only when users depend on them. Agents care more about clear names, descriptions, and repairable errors than exact legacy flag layout.