# Context & Global Options

URL: /docs/usage/context/
Section: usage
Tags: context, global-options, verbosity

--------------------------------------------------------------------------------

The Context carries execution metadata — verbosity level, output format, color preference, and user-defined global options — to every command handler. Injecting context Add a ctx: Context parameter to any command handler. The CLI dispatcher injects it automatically and excludes it from argparse and MCP schemas: from milo import CLI, Context cli = CLI(name="myapp") @cli.command("build", description="Build the site") def build(output: str = "_site", ctx: Context = None) -> str: ctx.log("Starting build...", level=1) # only shown with --verbose ctx.log(f"Output dir: {output}", level=2) # only shown with -vv return f"Built to {output}" Verbosity levels The CLI maps flags to verbosity integers: Flag ctx.verbosity Property -q / --quiet -1 ctx.quiet == True (default) 0 — -v / --verbose 1 ctx.verbose == True -vv 2 ctx.debug == True Use ctx.log() to print messages at specific verbosity levels: ctx.log("Always shown unless quiet", level=0) ctx.log("Verbose detail", level=1) ctx.log("Debug trace", level=2) Messages go to stderr, keeping stdout clean for structured output. Global options Register CLI-wide options that are available on every command via ctx.globals: cli.global_option("environment", short="-e", default="local", description="Target environment") cli.global_option("dry_run", is_flag=True, description="Simulate without making changes") Access them in handlers: @cli.command("deploy", description="Deploy the app") def deploy(service: str, ctx: Context = None) -> dict: env = ctx.globals.get("environment", "local") dry = ctx.globals.get("dry_run", False) if dry: return {"action": "dry-run", "service": service, "env": env} return {"action": "deployed", "service": service, "env": env} myapp deploy --service api -e staging --dry-run get_context() For library code that doesn't have direct access to the ctx parameter, use get_context(): from milo import get_context def helper(): ctx = get_context() ctx.log("Called from library code", level=1) get_context() uses a ContextVar set by the CLI dispatcher. If no context has been set, it returns a default Context. Running interactive apps from commands Use ctx.run_app() to launch an interactive App from within a CLI command handler. The command blocks while the app runs and receives the final state when it exits: from dataclasses import dataclass from milo import CLI, Context, quit_on, with_cursor, with_confirm, SpecialKey cli = CLI(name="picker") @dataclass(frozen=True, slots=True) class PickState: items: tuple[str, ...] = ("alpha", "beta", "gamma") cursor: int = 0 @with_confirm() @with_cursor("items", wrap=True) @quit_on(SpecialKey.ESCAPE) def reducer(state, action): if state is None: return PickState() return state @cli.command("pick", description="Pick an item") def pick(ctx: Context = None) -> str: state = ctx.run_app(reducer, template="pick.kida", initial_state=PickState()) return state.items[state.cursor] This bridges the CLI dispatch layer with the Elm Architecture event loop — the command defines what to run, the app handles how to interact. Context fields Field Type Description verbosity int -1=quiet, 0=normal, 1=verbose, 2=debug format str Output format: "plain", "json", "table" color bool Whether color output is enabled globals dict Values from user-defined global options Tip Tip Combine with Configuration to let global options control config loading — for example, a --profile option that selects a config profile.

--------------------------------------------------------------------------------

Metadata:
- Author: lbliii
- Word Count: 452
- Reading Time: 2 minutes