docs(maestro): bare maestro opens the TUI

Turns each sidebar row into a card: name plus actions on line 1, an
adaptive meta line below carrying a colour-coded activity dot, the time
held in that state, any agent-reported detail, and the blocked-work or
exited markers that used to crowd the name row.

Renders the activity dimension the daemon already inferred and adds an
Error state fed by a Claude Code hook, which maestro installs globally
and addresses per session through MAESTRO_SESSION_ID / MAESTRO_URL.
Both clients implement one contract, docs/SIDEBAR.md.

Closes #101, #102, #103, #104, #105, #106, #107, #108, #110, #111, #112,
#113, #114, #115.

crates/maestro/src/main.rs

@@ -19,8 +19,7 @@ use tracing_subscriber::EnvFilter;
 #[command(
     name = "maestro",
     version,
-    about = "Unified CLI / daemon / TUI for the Maestro terminal-session orchestrator",
-    arg_required_else_help = true
+    about = "Unified CLI / daemon / TUI for the Maestro terminal-session orchestrator"
 )]
 struct Cli {
     /// Override the daemon HTTP base clients talk to (e.g.
@@ -37,8 +36,11 @@ struct Cli {
     #[arg(short, long, global = true, action = clap::ArgAction::Count)]
     verbose: u8,
 
+    /// A missing subcommand defaults to the TUI (#119): a bare `maestro` opens
+    /// the terminal UI. Builds without the `tui` feature have no UI surface,
+    /// so they print help and exit 0 instead.
     #[command(subcommand)]
-    command: Command,
+    command: Option<Command>,
 }
 
 #[derive(Debug, Subcommand)]
@@ -89,7 +91,22 @@ fn main() -> ExitCode {
 }
 
 async fn dispatch(cli: Cli) -> Result<(), Box<dyn std::error::Error>> {
-    match cli.command {
+    let command = match cli.command {
+        Some(command) => command,
+        None => {
+            #[cfg(feature = "tui")]
+            {
+                Command::Tui(maestro_tui::cli::TuiArgs { daemon_url: None })
+            }
+            #[cfg(not(feature = "tui"))]
+            {
+                use clap::CommandFactory;
+                let _ = <Cli as CommandFactory>::command().print_help();
+                return Ok(());
+            }
+        }
+    };
+    match command {
         #[cfg(feature = "cli")]
         Command::List(args) => {
             maestro_cli::dispatch(
@@ -166,19 +183,19 @@ fn init_tracing(cli: &Cli) {
 }
 
 #[cfg(feature = "cli")]
-fn is_cli_subcommand(command: &Command) -> bool {
+fn is_cli_subcommand(command: &Option<Command>) -> bool {
     matches!(
         command,
-        Command::List(_)
-            | Command::Spawn(_)
-            | Command::Attach(_)
-            | Command::Kill(_)
-            | Command::Hooks(_)
+        Some(Command::List(_))
+            | Some(Command::Spawn(_))
+            | Some(Command::Attach(_))
+            | Some(Command::Kill(_))
+            | Some(Command::Hooks(_))
     )
 }
 
 #[cfg(not(feature = "cli"))]
-fn is_cli_subcommand(_command: &Command) -> bool {
+fn is_cli_subcommand(_command: &Option<Command>) -> bool {
     false
 }
 
@@ -216,12 +233,20 @@ mod tests {
     }
 
     /// Parse argv the way `main` does, returning just the dispatched subcommand.
-    fn command_of(argv: &[&str]) -> Command {
+    fn command_of(argv: &[&str]) -> Option<Command> {
         Cli::try_parse_from(argv)
             .unwrap_or_else(|e| panic!("parse {argv:?}: {e}"))
             .command
     }
 
+    #[test]
+    fn bare_invocation_parses_to_no_subcommand() {
+        // The TUI-vs-help default is applied in `dispatch`; parsing must not
+        // reject an empty argv.
+        assert!(command_of(&["maestro"]).is_none());
+        assert!(command_of(&["maestro", "--verbose"]).is_none());
+    }
+
     #[cfg(feature = "cli")]
     #[test]
     fn cli_subcommands_are_classified_as_cli() {

crates/maestro/tests/cli.rs

@@ -54,11 +54,35 @@ fn version_flag_succeeds() {
     assert!(text.contains("maestro"), "--version output: {text}");
 }
 
+/// A bare `maestro` must never fall back to help on a build that has a TUI:
+/// the missing subcommand defaults to `tui` (#119). Point at a port with
+/// nothing listening so the TUI's health probe fails fast instead of blocking
+/// on a terminal.
+#[cfg(feature = "tui")]
 #[test]
-fn no_args_prints_help_and_fails() {
-    // `arg_required_else_help = true` => exit non-zero but show usage.
+fn bare_invocation_dispatches_to_the_tui() {
+    let (ok, text) = run(&["--daemon-url", "http://127.0.0.1:9"]);
+    assert!(
+        !ok,
+        "TUI against a dead daemon should exit non-zero:\n{text}"
+    );
+    assert!(
+        text.contains("daemon unreachable"),
+        "bare invocation should have run the TUI's daemon probe:\n{text}"
+    );
+    assert!(
+        !text.contains("Usage"),
+        "bare invocation must not print help when a TUI exists:\n{text}"
+    );
+}
+
+/// Builds without the `tui` feature keep the historical behaviour: no args =>
+/// help, exit 0 (#119).
+#[cfg(not(feature = "tui"))]
+#[test]
+fn bare_invocation_prints_help_and_exits_zero() {
     let (ok, text) = run(&[]);
-    assert!(!ok, "bare invocation should fail:\n{text}");
+    assert!(ok, "bare invocation should exit 0:\n{text}");
     assert!(text.contains("Usage"), "expected usage text:\n{text}");
 }
 

docs/INSTALL.md

@@ -119,6 +119,9 @@ The wizard always installs the default-feature build.
 
 `maestro tui` is the keyboard-and-mouse driven terminal UI client. It ships
 in the default feature set, so a vanilla `cargo install maestro` builds it.
+A bare `maestro` opens the TUI too — the missing subcommand defaults to `tui`
+(#119), so `maestro --daemon-url http://host:7070` works as well. Builds
+without the `tui` feature have no UI to open and print help instead (exit 0).
 Drop the `tui` feature to skip it on hosts that don't need the UI surface
 (`--no-default-features --features cli,daemon`).