diff --git a/music_cli/cli.py b/music_cli/cli.py
index 9136037..11d4b22 100644
--- a/music_cli/cli.py
+++ b/music_cli/cli.py
@@ -150,7 +150,38 @@ def start_daemon_background() -> None:
         )
 
 
-@click.group(invoke_without_command=True)
+class AliasedGroup(click.Group):
+    """Click group that supports hidden command aliases.
+
+    Aliases are registered as a mapping from alias name to real command name.
+    They are hidden from --help output but fully functional.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._aliases: dict[str, str] = {}
+
+    def add_alias(self, alias: str, target: str) -> None:
+        """Register *alias* as a hidden forwarding name for *target*."""
+        self._aliases[alias] = target
+
+    def get_command(self, ctx, cmd_name):
+        """Resolve aliases before normal lookup."""
+        # Check if the cmd_name is an alias
+        real_name = self._aliases.get(cmd_name, cmd_name)
+        return super().get_command(ctx, real_name)
+
+    def format_usage(self, ctx, formatter):
+        """Standard usage — aliases stay hidden."""
+        super().format_usage(ctx, formatter)
+
+
+def _register_alias(group: AliasedGroup, alias: str, target: str) -> None:
+    """Register a hidden alias on an AliasedGroup."""
+    group.add_alias(alias, target)
+
+
+@click.group(cls=AliasedGroup, invoke_without_command=True)
 @click.version_option(__version__)
 @click.pass_context
 def main(ctx):
@@ -162,6 +193,9 @@ def main(ctx):
     # Check for updates on any command
     if ctx.invoked_subcommand is not None:
         _check_for_updates_once()
+    elif ctx.invoked_subcommand is None:
+        # Bare invocation: show status
+        ctx.invoke(status)
 
 
 @main.command()
@@ -175,6 +209,7 @@ def main(ctx):
 @click.option("--source", "-s", help="Source file/URL/station name")
 @click.option(
     "--mood",
+    "-M",
     type=click.Choice(
         ["happy", "sad", "excited", "focus", "relaxed", "energetic", "melancholic", "peaceful"]
     ),
@@ -192,6 +227,7 @@ def play(mode, source, mood, auto, duration, index):
       music-cli play -m local -s song.mp3  # Play local file
       music-cli play -m radio -s "chill"   # Play radio station by name
       music-cli play --mood focus       # Play focus music
+      music-cli play -M focus           # Play focus music (short flag)
       music-cli play -m ai --mood happy # Generate happy AI music
       music-cli play -m history -i 3    # Replay 3rd item from history
       music-cli play -m local --auto    # Shuffle local library
@@ -366,15 +402,16 @@ def next_track():
         sys.exit(1)
 
 
-@main.command()
+@main.command("vol")
 @click.argument("level", type=int, required=False)
 def volume(level):
     """Get or set volume (0-100).
 
     \b
     Examples:
-      music-cli volume      # Show current volume
-      music-cli volume 50   # Set volume to 50%
+      mc vol            # Show current volume
+      mc vol 50         # Set volume to 50%
+      music-cli volume  # Old name still works
     """
     client = ensure_daemon()
 
@@ -390,7 +427,7 @@ def volume(level):
         sys.exit(1)
 
 
-@main.group("radios", invoke_without_command=True)
+@main.group("radio", cls=AliasedGroup, invoke_without_command=True)
 @click.pass_context
 def radios_group(ctx):
     """Manage radio stations.
@@ -404,11 +441,11 @@ def radios_group(ctx):
 
     \b
     Examples:
-      music-cli radios              # List all stations
-      music-cli radios list         # List all stations
-      music-cli radios play 5       # Play station #5
-      music-cli radios add          # Add new station interactively
-      music-cli radios remove 3     # Remove station #3
+      mc radio              # List all stations
+      mc radio list         # List all stations
+      mc radio play 5       # Play station #5
+      mc radio add          # Add new station interactively
+      mc radio remove 3     # Remove station #3
     """
     if ctx.invoked_subcommand is None:
         # Default action: list radios
@@ -679,7 +716,7 @@ def show_config():
     click.echo(f"  PID:           {config.pid_file}")
 
 
-@main.command("moods")
+@main.command("mood")
 def list_moods():
     """List available mood tags."""
     from .context.mood import MoodContext
@@ -687,10 +724,10 @@ def list_moods():
     click.echo("Available moods:")
     for mood in MoodContext.get_all_moods():
         click.echo(f"  - {mood}")
-    click.echo("\nUse with: music-cli play --mood <mood>")
+    click.echo("\nUse with: mc play --mood <mood>")
 
 
-@main.group("ai", invoke_without_command=True)
+@main.group("ai", cls=AliasedGroup, invoke_without_command=True)
 @click.pass_context
 def ai_group(ctx):
     """Manage AI-generated music tracks.
@@ -754,6 +791,7 @@ def ai_list():
 @click.option("-p", "--prompt", help="Custom prompt for AI music generation")
 @click.option(
     "--mood",
+    "-M",
     type=click.Choice(
         ["happy", "sad", "excited", "focus", "relaxed", "energetic", "melancholic", "peaceful"]
     ),
@@ -1143,31 +1181,31 @@ def ai_remove(index):
         sys.exit(1)
 
 
-@main.group("youtube", invoke_without_command=True)
+@main.group("yt", cls=AliasedGroup, invoke_without_command=True)
 @click.pass_context
 def youtube_group(ctx):
     """Manage cached YouTube audio for offline playback.
 
-    \\b
+    \b
     Commands:
-      cached        - Show all cached YouTube tracks (default)
+      list          - Show all cached YouTube tracks (default)
       play <number> - Play a cached track by number (offline)
       remove <num>  - Remove a cached track
       clear         - Clear all cached tracks
 
-    \\b
+    \b
     Examples:
-      music-cli youtube              # List cached tracks
-      music-cli youtube cached       # List cached tracks
-      music-cli youtube play 3       # Play cached track #3
-      music-cli youtube remove 1     # Remove track #1
-      music-cli youtube clear        # Clear entire cache
+      mc yt              # List cached tracks
+      mc yt list         # List cached tracks
+      mc yt play 3       # Play cached track #3
+      mc yt remove 1     # Remove track #1
+      mc yt clear        # Clear entire cache
     """
     if ctx.invoked_subcommand is None:
         ctx.invoke(youtube_cached)
 
 
-@youtube_group.command("cached")
+@youtube_group.command("list")
 def youtube_cached():
     client = ensure_daemon()
 
@@ -1352,5 +1390,27 @@ def update_radios():
     click.echo(f"Config version updated to {__version__}")
 
 
+# ---------------------------------------------------------------------------
+# Register aliases (hidden — don't appear in --help but work on the CLI)
+# ---------------------------------------------------------------------------
+
+# Task 1.3: Old group/command names → hidden aliases on main
+_register_alias(main, "radios", "radio")
+_register_alias(main, "youtube", "yt")
+_register_alias(main, "moods", "mood")
+_register_alias(main, "volume", "vol")
+
+# Task 1.4: Playback single-letter/short aliases
+_register_alias(main, "s", "stop")
+_register_alias(main, "pp", "pause")
+_register_alias(main, "r", "resume")
+_register_alias(main, "n", "next")
+_register_alias(main, "st", "status")
+_register_alias(main, "h", "history")
+
+# Task 1.3: Inside yt group, "cached" → "list"
+_register_alias(youtube_group, "cached", "list")
+
+
 if __name__ == "__main__":
     main()
diff --git a/pyproject.toml b/pyproject.toml
index cc69340..56886df 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,6 +65,7 @@ dev = [
 
 [project.scripts]
 music-cli = "music_cli.cli:main"
+mc = "music_cli.cli:main"
 
 [project.urls]
 Homepage = "https://github.com/luongnv89/music-cli"
diff --git a/tests/test_cli.py b/tests/test_cli.py
new file mode 100644
index 0000000..6f9450f
--- /dev/null
+++ b/tests/test_cli.py
@@ -0,0 +1,242 @@
+"""Tests for CLI v2 Phase 1: Foundation — mc alias, short names, playback aliases."""
+
+import pytest
+from click.testing import CliRunner
+
+from music_cli.cli import main
+
+
+@pytest.fixture
+def runner():
+    """Create a Click CliRunner."""
+    return CliRunner()
+
+
+# -------------------------------------------------------------------------
+# 1.1 — mc entry point (both entry points share the same `main` group)
+# -------------------------------------------------------------------------
+
+
+class TestHelpOutput:
+    """Verify --help contains expected commands with new names."""
+
+    def test_help_shows_new_group_names(self, runner):
+        result = runner.invoke(main, ["--help"])
+        assert result.exit_code == 0
+        # New primary names must appear
+        for cmd in ("radio", "yt", "mood", "vol"):
+            assert cmd in result.output
+
+    def test_help_hides_old_group_names(self, runner):
+        result = runner.invoke(main, ["--help"])
+        assert result.exit_code == 0
+        # Old names must NOT appear in the help listing
+        # They should still work as hidden aliases
+        for old in ("radios", "youtube", "moods", "volume"):
+            # Make sure the old name doesn't appear as a listed command.
+            # We check it doesn't appear on a line starting with whitespace (command listing).
+            lines = result.output.splitlines()
+            command_lines = [l.strip().split()[0] for l in lines if l.startswith("  ") and l.strip()]
+            assert old not in command_lines, f"Old name '{old}' should be hidden from --help"
+
+    def test_help_hides_playback_aliases(self, runner):
+        result = runner.invoke(main, ["--help"])
+        assert result.exit_code == 0
+        lines = result.output.splitlines()
+        command_lines = [l.strip().split()[0] for l in lines if l.startswith("  ") and l.strip()]
+        for alias in ("s", "pp", "r", "n", "st", "h"):
+            assert alias not in command_lines, f"Alias '{alias}' should be hidden from --help"
+
+    def test_help_shows_expected_commands(self, runner):
+        result = runner.invoke(main, ["--help"])
+        assert result.exit_code == 0
+        for cmd in ("play", "stop", "pause", "resume", "next", "status", "history",
+                     "radio", "yt", "mood", "vol", "ai", "daemon", "config"):
+            assert cmd in result.output
+
+    def test_version(self, runner):
+        result = runner.invoke(main, ["--version"])
+        assert result.exit_code == 0
+        assert "version" in result.output.lower()
+
+
+# -------------------------------------------------------------------------
+# 1.2 + 1.3 — Alias infrastructure & renamed groups
+# -------------------------------------------------------------------------
+
+
+class TestGroupRenames:
+    """Old group names resolve to the same commands as new names."""
+
+    def test_radio_help(self, runner):
+        result = runner.invoke(main, ["radio", "--help"])
+        assert result.exit_code == 0
+        assert "radio" in result.output.lower()
+
+    def test_radios_alias_resolves(self, runner):
+        result = runner.invoke(main, ["radios", "--help"])
+        assert result.exit_code == 0
+        assert "radio" in result.output.lower()
+
+    def test_yt_help(self, runner):
+        result = runner.invoke(main, ["yt", "--help"])
+        assert result.exit_code == 0
+        assert "youtube" in result.output.lower() or "yt" in result.output.lower()
+
+    def test_youtube_alias_resolves(self, runner):
+        result = runner.invoke(main, ["youtube", "--help"])
+        assert result.exit_code == 0
+
+    def test_mood_help(self, runner):
+        result = runner.invoke(main, ["mood", "--help"])
+        assert result.exit_code == 0
+
+    def test_moods_alias_resolves(self, runner):
+        result = runner.invoke(main, ["moods", "--help"])
+        assert result.exit_code == 0
+
+    def test_vol_help(self, runner):
+        result = runner.invoke(main, ["vol", "--help"])
+        assert result.exit_code == 0
+        assert "volume" in result.output.lower()
+
+    def test_volume_alias_resolves(self, runner):
+        result = runner.invoke(main, ["volume", "--help"])
+        assert result.exit_code == 0
+        assert "volume" in result.output.lower()
+
+    def test_yt_cached_alias(self, runner):
+        """'yt cached' should resolve to 'yt list' (hidden alias)."""
+        result = runner.invoke(main, ["yt", "cached", "--help"])
+        assert result.exit_code == 0
+
+    def test_yt_list_help(self, runner):
+        result = runner.invoke(main, ["yt", "list", "--help"])
+        assert result.exit_code == 0
+
+
+# -------------------------------------------------------------------------
+# 1.4 — Playback command aliases
+# -------------------------------------------------------------------------
+
+
+class TestPlaybackAliases:
+    """Single-letter and short aliases resolve to real commands."""
+
+    @pytest.mark.parametrize(
+        "alias,target_cmd",
+        [
+            ("s", "stop"),
+            ("pp", "pause"),
+            ("r", "resume"),
+            ("n", "next"),
+            ("st", "status"),
+            ("h", "history"),
+        ],
+    )
+    def test_alias_resolves_to_help(self, runner, alias, target_cmd):
+        """Each alias should resolve without error when given --help."""
+        result = runner.invoke(main, [alias, "--help"])
+        assert result.exit_code == 0, f"Alias '{alias}' failed: {result.output}"
+
+    @pytest.mark.parametrize(
+        "alias,target_cmd",
+        [
+            ("s", "stop"),
+            ("pp", "pause"),
+            ("r", "resume"),
+            ("n", "next"),
+            ("st", "status"),
+            ("h", "history"),
+        ],
+    )
+    def test_alias_help_matches_target(self, runner, alias, target_cmd):
+        """Alias help output should match the target command help output."""
+        alias_result = runner.invoke(main, [alias, "--help"])
+        target_result = runner.invoke(main, [target_cmd, "--help"])
+        # The help text body should be the same (ignoring the usage line which
+        # shows the invoked name)
+        alias_body = "\n".join(alias_result.output.splitlines()[1:])
+        target_body = "\n".join(target_result.output.splitlines()[1:])
+        assert alias_body == target_body
+
+
+# -------------------------------------------------------------------------
+# 1.5 — Bare invocation → status
+# -------------------------------------------------------------------------
+
+
+class TestBareInvocation:
+    """Bare `mc` (no subcommand) should invoke status."""
+
+    def test_bare_invocation_does_not_crash(self, runner):
+        """Bare invocation should not crash (exit code 0 or 1 for daemon not running)."""
+        result = runner.invoke(main, [])
+        # We accept exit_code 1 because the daemon likely isn't running in test,
+        # but it must not be exit_code 2 (Click usage error).
+        assert result.exit_code in (0, 1), (
+            f"Bare invocation crashed with exit code {result.exit_code}: {result.output}"
+        )
+
+    def test_bare_invocation_attempts_status(self, runner):
+        """Bare invocation should try to show status (connect to daemon)."""
+        result = runner.invoke(main, [])
+        # Either shows status output or a connection error — both prove status was invoked
+        output_lower = result.output.lower()
+        assert (
+            "status" in output_lower
+            or "error" in output_lower
+            or "daemon" in output_lower
+            or "starting" in output_lower
+        ), f"Bare invocation did not attempt status: {result.output}"
+
+
+# -------------------------------------------------------------------------
+# 1.6 — -M short flag for --mood
+# -------------------------------------------------------------------------
+
+
+class TestMoodShortFlag:
+    """The -M flag works on both play and ai play."""
+
+    def test_play_has_mood_short_flag(self, runner):
+        result = runner.invoke(main, ["play", "--help"])
+        assert result.exit_code == 0
+        assert "-M" in result.output
+
+    def test_ai_play_has_mood_short_flag(self, runner):
+        result = runner.invoke(main, ["ai", "play", "--help"])
+        assert result.exit_code == 0
+        assert "-M" in result.output
+
+
+# -------------------------------------------------------------------------
+# Integration: all subcommand --help should resolve cleanly
+# -------------------------------------------------------------------------
+
+
+class TestSubcommandHelp:
+    """Every primary command/group shows --help without errors."""
+
+    @pytest.mark.parametrize(
+        "cmd_args",
+        [
+            ["play", "--help"],
+            ["stop", "--help"],
+            ["pause", "--help"],
+            ["resume", "--help"],
+            ["next", "--help"],
+            ["status", "--help"],
+            ["history", "--help"],
+            ["radio", "--help"],
+            ["yt", "--help"],
+            ["mood", "--help"],
+            ["vol", "--help"],
+            ["ai", "--help"],
+            ["daemon", "--help"],
+            ["config", "--help"],
+        ],
+    )
+    def test_command_help_succeeds(self, runner, cmd_args):
+        result = runner.invoke(main, cmd_args)
+        assert result.exit_code == 0, f"Failed for {cmd_args}: {result.output}"