diff --git a/src/led_sync/models.py b/src/led_sync/models.py
new file mode 100644
index 0000000..4c7e1cb
--- /dev/null
+++ b/src/led_sync/models.py
@@ -0,0 +1,96 @@
+"""Choreography data model for LED Sync Studio.
+
+Implements ChoreoEvent and ChoreoFile Pydantic v2 models per CONTEXT.md D-01/D-02/D-03.
+
+Valid zones: schrank, wand, all (from docs/protocol.md)
+Valid animations: chase, pulse, rainbow, strobe, color_wash, breathe, sparkle, gradient_sweep
+
+File extension convention: .choreo.json (D-03)
+Events are always sorted by timestamp (D-02).
+"""
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Optional
+
+from pydantic import BaseModel, field_validator
+
+VALID_ZONES: set[str] = {"schrank", "wand", "all"}
+
+VALID_ANIMATIONS: set[str] = {
+    "chase",
+    "pulse",
+    "rainbow",
+    "strobe",
+    "color_wash",
+    "breathe",
+    "sparkle",
+    "gradient_sweep",
+}
+
+
+class ChoreoEvent(BaseModel):
+    """A single choreography event: at `timestamp` seconds, trigger `animation` on `zone`."""
+
+    timestamp: float  # seconds from song start; must be >= 0
+    zone: str  # "schrank" | "wand" | "all"
+    animation: str  # must match ESP32 animation names from docs/protocol.md
+    params: dict  # speed, intensity, colors, direction — forwarded as-is to ESP32
+    loop: Optional[int] = None  # None = play once; N = repeat N times
+    duration: Optional[float] = None  # seconds; None = run until next event
+
+    @field_validator("timestamp")
+    @classmethod
+    def validate_timestamp(cls, v: float) -> float:
+        if v < 0:
+            raise ValueError("timestamp must be >= 0")
+        return v
+
+    @field_validator("zone")
+    @classmethod
+    def validate_zone(cls, v: str) -> str:
+        if v not in VALID_ZONES:
+            raise ValueError(
+                f"Invalid zone: {v!r}. Must be one of {sorted(VALID_ZONES)}"
+            )
+        return v
+
+    @field_validator("animation")
+    @classmethod
+    def validate_animation(cls, v: str) -> str:
+        if v not in VALID_ANIMATIONS:
+            raise ValueError(
+                f"Unknown animation: {v!r}. Must be one of {sorted(VALID_ANIMATIONS)}"
+            )
+        return v
+
+
+class ChoreoFile(BaseModel):
+    """A choreography file: song path, optional BPM, and a sorted list of events.
+
+    Events are always kept sorted by timestamp (D-02).
+    Persist with .choreo.json extension (D-03).
+    """
+
+    song_path: str
+    bpm: Optional[float] = None
+    events: list[ChoreoEvent] = []
+
+    def model_post_init(self, __context: object) -> None:
+        """Sort events by timestamp on initialization (D-02)."""
+        self.events = sorted(self.events, key=lambda e: e.timestamp)
+
+    def add_event(self, event: ChoreoEvent) -> None:
+        """Insert an event and re-sort by timestamp."""
+        self.events.append(event)
+        self.events.sort(key=lambda e: e.timestamp)
+
+    def save(self, path: str | Path) -> None:
+        """Write choreography to a .choreo.json file."""
+        Path(path).write_text(self.model_dump_json(indent=2))
+
+    @classmethod
+    def load(cls, path: str | Path) -> "ChoreoFile":
+        """Load a choreography from a .choreo.json file. Events will be sorted."""
+        return cls.model_validate_json(Path(path).read_text())
diff --git a/tests/test_models.py b/tests/test_models.py
new file mode 100644
index 0000000..a8710b9
--- /dev/null
+++ b/tests/test_models.py
@@ -0,0 +1,212 @@
+"""TDD: Tests for ChoreoEvent and ChoreoFile Pydantic v2 models.
+
+Tests cover:
+- Field validation (zone, animation, timestamp)
+- File save/load roundtrip
+- Event sorting by timestamp
+- add_event() re-sorts
+"""
+import json
+import tempfile
+from pathlib import Path
+
+import pytest
+from pydantic import ValidationError
+
+
+# --- RED: these imports will fail until models.py exists ---
+def import_models():
+    from led_sync.models import ChoreoEvent, ChoreoFile, VALID_ZONES, VALID_ANIMATIONS
+    return ChoreoEvent, ChoreoFile, VALID_ZONES, VALID_ANIMATIONS
+
+
+class TestChoreoEventValidation:
+    def test_valid_event_creation(self):
+        ChoreoEvent, _, _, _ = import_models()
+        e = ChoreoEvent(
+            timestamp=1.5,
+            zone="wand",
+            animation="chase",
+            params={"speed": 0.5},
+        )
+        assert e.timestamp == 1.5
+        assert e.zone == "wand"
+        assert e.animation == "chase"
+        assert e.params == {"speed": 0.5}
+        assert e.loop is None
+        assert e.duration is None
+
+    def test_all_valid_zones_accepted(self):
+        ChoreoEvent, _, VALID_ZONES, _ = import_models()
+        for zone in VALID_ZONES:
+            e = ChoreoEvent(timestamp=0, zone=zone, animation="pulse", params={})
+            assert e.zone == zone
+
+    def test_invalid_zone_rejected(self):
+        ChoreoEvent, _, _, _ = import_models()
+        with pytest.raises(ValidationError) as exc_info:
+            ChoreoEvent(timestamp=1.0, zone="bedroom", animation="chase", params={})
+        assert "Invalid zone" in str(exc_info.value)
+
+    def test_all_valid_animations_accepted(self):
+        ChoreoEvent, _, _, VALID_ANIMATIONS = import_models()
+        for anim in VALID_ANIMATIONS:
+            e = ChoreoEvent(timestamp=0, zone="wand", animation=anim, params={})
+            assert e.animation == anim
+
+    def test_invalid_animation_rejected(self):
+        ChoreoEvent, _, _, _ = import_models()
+        with pytest.raises(ValidationError) as exc_info:
+            ChoreoEvent(timestamp=1.0, zone="wand", animation="disco", params={})
+        assert "Unknown animation" in str(exc_info.value)
+
+    def test_negative_timestamp_rejected(self):
+        ChoreoEvent, _, _, _ = import_models()
+        with pytest.raises(ValidationError):
+            ChoreoEvent(timestamp=-1.0, zone="wand", animation="chase", params={})
+
+    def test_zero_timestamp_accepted(self):
+        ChoreoEvent, _, _, _ = import_models()
+        e = ChoreoEvent(timestamp=0.0, zone="schrank", animation="breathe", params={})
+        assert e.timestamp == 0.0
+
+    def test_loop_and_duration_optional(self):
+        ChoreoEvent, _, _, _ = import_models()
+        e = ChoreoEvent(
+            timestamp=2.0,
+            zone="all",
+            animation="rainbow",
+            params={},
+            loop=3,
+            duration=5.0,
+        )
+        assert e.loop == 3
+        assert e.duration == 5.0
+
+
+class TestChoreoFileBasics:
+    def test_empty_choreofile_creation(self):
+        _, ChoreoFile, _, _ = import_models()
+        cf = ChoreoFile(song_path="test.mp3")
+        assert cf.song_path == "test.mp3"
+        assert cf.bpm is None
+        assert cf.events == []
+
+    def test_choreofile_with_bpm(self):
+        _, ChoreoFile, _, _ = import_models()
+        cf = ChoreoFile(song_path="test.mp3", bpm=120.0)
+        assert cf.bpm == 120.0
+
+
+class TestChoreoFileSortingAndAdd:
+    def test_events_sorted_on_load(self):
+        ChoreoEvent, ChoreoFile, _, _ = import_models()
+        e1 = ChoreoEvent(timestamp=3.0, zone="wand", animation="chase", params={})
+        e2 = ChoreoEvent(timestamp=1.0, zone="wand", animation="pulse", params={})
+        e3 = ChoreoEvent(timestamp=2.0, zone="schrank", animation="rainbow", params={})
+        cf = ChoreoFile(song_path="test.mp3", events=[e1, e2, e3])
+        timestamps = [e.timestamp for e in cf.events]
+        assert timestamps == sorted(timestamps), "Events must be sorted by timestamp"
+
+    def test_add_event_maintains_sort(self):
+        ChoreoEvent, ChoreoFile, _, _ = import_models()
+        cf = ChoreoFile(song_path="test.mp3")
+        cf.add_event(ChoreoEvent(timestamp=5.0, zone="wand", animation="strobe", params={}))
+        cf.add_event(ChoreoEvent(timestamp=1.0, zone="wand", animation="chase", params={}))
+        cf.add_event(ChoreoEvent(timestamp=3.0, zone="all", animation="pulse", params={}))
+        timestamps = [e.timestamp for e in cf.events]
+        assert timestamps == [1.0, 3.0, 5.0]
+
+
+class TestChoreoFileRoundtrip:
+    def test_save_creates_json_file(self):
+        ChoreoEvent, ChoreoFile, _, _ = import_models()
+        cf = ChoreoFile(song_path="my_song.mp3", bpm=128.0)
+        e = ChoreoEvent(timestamp=1.5, zone="wand", animation="chase", params={"speed": 0.5})
+        cf.add_event(e)
+
+        with tempfile.NamedTemporaryFile(suffix=".choreo.json", delete=False) as f:
+            tmp = Path(f.name)
+
+        try:
+            cf.save(tmp)
+            assert tmp.exists()
+            data = json.loads(tmp.read_text())
+            assert data["song_path"] == "my_song.mp3"
+            assert data["bpm"] == 128.0
+            assert len(data["events"]) == 1
+            assert data["events"][0]["timestamp"] == 1.5
+        finally:
+            tmp.unlink(missing_ok=True)
+
+    def test_load_roundtrip_preserves_all_fields(self):
+        ChoreoEvent, ChoreoFile, _, _ = import_models()
+        e1 = ChoreoEvent(timestamp=1.5, zone="wand", animation="chase", params={"speed": 0.5})
+        e2 = ChoreoEvent(
+            timestamp=0.5,
+            zone="schrank",
+            animation="strobe",
+            params={"intensity": 0.8},
+            loop=2,
+            duration=3.0,
+        )
+        e3 = ChoreoEvent(timestamp=3.0, zone="all", animation="rainbow", params={})
+        original = ChoreoFile(song_path="test.mp3", bpm=120.0, events=[e1, e2, e3])
+
+        with tempfile.NamedTemporaryFile(suffix=".choreo.json", delete=False) as f:
+            tmp = Path(f.name)
+
+        try:
+            original.save(tmp)
+            loaded = ChoreoFile.load(tmp)
+            assert loaded.song_path == original.song_path
+            assert loaded.bpm == original.bpm
+            assert len(loaded.events) == 3
+            # Events should be sorted: 0.5, 1.5, 3.0
+            assert loaded.events[0].timestamp == 0.5
+            assert loaded.events[1].timestamp == 1.5
+            assert loaded.events[2].timestamp == 3.0
+            assert loaded.events[0].loop == 2
+            assert loaded.events[0].duration == 3.0
+        finally:
+            tmp.unlink(missing_ok=True)
+
+    def test_load_sorts_events_by_timestamp(self):
+        """Loading a file with unsorted events should produce sorted output."""
+        _, ChoreoFile, _, _ = import_models()
+        # Write raw JSON with unsorted events
+        raw = {
+            "song_path": "test.mp3",
+            "bpm": None,
+            "events": [
+                {"timestamp": 3.0, "zone": "wand", "animation": "chase", "params": {}, "loop": None, "duration": None},
+                {"timestamp": 1.0, "zone": "wand", "animation": "pulse", "params": {}, "loop": None, "duration": None},
+                {"timestamp": 2.0, "zone": "all", "animation": "rainbow", "params": {}, "loop": None, "duration": None},
+            ],
+        }
+        with tempfile.NamedTemporaryFile(
+            suffix=".choreo.json", mode="w", delete=False
+        ) as f:
+            json.dump(raw, f)
+            tmp = Path(f.name)
+
+        try:
+            loaded = ChoreoFile.load(tmp)
+            timestamps = [e.timestamp for e in loaded.events]
+            assert timestamps == [1.0, 2.0, 3.0]
+        finally:
+            tmp.unlink(missing_ok=True)
+
+
+class TestExportedConstants:
+    def test_valid_zones_exported(self):
+        _, _, VALID_ZONES, _ = import_models()
+        assert "schrank" in VALID_ZONES
+        assert "wand" in VALID_ZONES
+        assert "all" in VALID_ZONES
+        assert len(VALID_ZONES) == 3
+
+    def test_valid_animations_exported(self):
+        _, _, _, VALID_ANIMATIONS = import_models()
+        expected = {"chase", "pulse", "rainbow", "strobe", "color_wash", "breathe", "sparkle", "gradient_sweep"}
+        assert VALID_ANIMATIONS == expected