Koru Standard Library: std/cli — a command surface for programs. import std/cli std/cli:flag(verbose) { "type": "boolean", // boolean | string | int | float "short": "v", "description": "chatter" } std/cli:command(run) { "description": "run the thing", "alias": "r", "subcommands": ["check", "fire"] } std/cli() | run { subcommand, file: string, verbose } |> handle(subcommand, file, verbose) | build |> build_all() | usage { message } |> complain(message) | help { text } |> std/io:print.ln(text) The declares are [comptime|norun] Source records — the compiler.kz flag.declare/command.declare idiom, name as the positional arg, metadata in the block body. `std/cli()` resolves to this module's `default` tor — a [keyword|comptime|transform] that harvests the declares from the program AST and the command arms from its own continuations, and emits an argv parser + generated --help + dispatch. The std/json:parse emit pattern end to end. THE DESTRUCTURE IS THE SCHEMA (the json:parse license): a field whose name matches a declared flag (`verbose`) binds the parsed flag value; the reserved name `subcommand` binds the first token after the command, constrained against the declare's "subcommands" list when one exists; every other field is a positional in written order, typed by its spec — `file: string` hands a []const u8, `count: i64` parses the token, `?string` admits a missing trailing argument, `[]string` binds the rest. Bare fields bind strings. A command arm with no matching `std/cli:command` declare still dispatches — declares carry prose (help text, alias, subcommand validation), arms carry shape. `| usage { message, help }` and `| help { text }` are optional arms. Absent: --help prints the generated text and exits 0; a usage fault prints the message + generated text and exits 2. Bare invocation (no command token) shows help and exits 0. Program name/version in the usage line are harvested from a std/build:app declaration when one exists (identity lives there, not here) and fall back to the entry-file stem.