[steveclarke]

Closes #32.

ucmix ls scenes failed with ✗ accepts 1 arg(s), received 0 — cobra's bare count message, which never says what the argument is. Since ls projects takes none, it read as though ls scenes should list everything.

Now:

$ ucmix ls scenes
✗ ls scenes needs a project name
run `ucmix ls projects` to see them — quote names that contain spaces

The quoting note earns its place: real project names look like 03.135 Main Live.proj, so the common failure is a forgotten quote, not an omitted argument. Unquoted, cobra sees three args and the same message fires — the hint has to cover both.

How

requireArgs (internal/cli/args.go) wraps a cobra.PositionalArgs validator and turns a wrong count into an errs.CLIError naming what the command wants, plus a hint pointing at how to find the value. When there's nothing better to say the hint falls back to the command's usage line:

$ ucmix verify
✗ verify needs a config file
usage: ucmix verify <config.yml>

Applied to every command that validates positional args: ls scenes, recall, store, rename, delete, channel, mix, send, get, fade, apply, verify, dump, and the profile subcommands. set uses ArbitraryArgs and never errors, so it's untouched.

Not done deliberately

• No cross-project ls scenes. The issue left that open; this stays a usage-message fix.
• No behavior changes beyond the error text. Same validators, same exit codes.

Known limitation, pre-existing

--no-color is not honored on the arg-validation path: ui.Init runs in PersistentPreRun, which cobra skips when Args validation fails, so ucmix --no-color ls scenes still emits ANSI. NO_COLOR=1 does work (the package-level initializer reads it). This predates the change — cobra's bare message was styled too — but this PR adds a second styled line there, so it's worth naming. Fixing it means restructuring Execute(), out of scope here.

Testing

• just test — 378 unit (was 373); table-driven TestRequireArgs covers valid counts, too few, too many, and the usage-line fallback (including that cobra's [flags] suffix is trimmed).
• just test-e2e — 75 BATS (was 72); new cases in test/errors.bats for ls scenes with no project, get/recall missing args, and the usage-line fallback.
• just lint, just vet clean.
• Against the real 32R (profile studiolive32r), read-only — nothing was written: ls projects, ls scenes "03.135 Main Live.proj", get line/ch1/mute, dump line/ch1, and --json output all still work. Also confirmed the arg errors for store, rename, delete, apply, and fade fire with the live profile current and exit non-zero without contacting the board, and that the unquoted ls scenes 03.135 Main Live.proj case produces the message above.
• The write commands themselves weren't exercised on hardware: this change only affects argument-count validation, which fails before any connection is opened, so writing to a live show-state board shared with other sessions would have modified real state for no added signal.

https://claude.ai/code/session_01Ggvmi2jXGiS5ffLr7Hfn6d