# BPM Enrichment Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Add a `bpm` field (tempo from Spotify audio-features) to every track object returned by the MCP server.

**Architecture:** A private `_enrich_with_bpm(sp, tracks)` helper in `spotify_client.py` batch-fetches audio features for a list of parsed track dicts (100 IDs per API call) and adds a `bpm` field in place. Each of the three track-returning functions stores the track `id` during parsing, then calls this helper before returning.

**Tech Stack:** Python 3.11+, spotipy (`sp.audio_features()`), no new dependencies.

---

### Task 1: Add `_enrich_with_bpm` helper

**Files:**
- Modify: `spotify_client.py` — add helper after `_format_duration`

- [ ] **Step 1: Add the helper function**

In `spotify_client.py`, insert the following function immediately after `_format_duration` (around line 58):

```python
def _enrich_with_bpm(sp: spotipy.Spotify, tracks: list[dict]) -> None:
    ids = [t["id"] for t in tracks]
    for i in range(0, len(ids), 100):
        chunk_ids = ids[i : i + 100]
        features = sp.audio_features(chunk_ids)
        for track, feat in zip(tracks[i : i + 100], features):
            track["bpm"] = round(feat["tempo"], 1) if feat else None
```

- [ ] **Step 2: Verify syntax**

```bash
cd /Users/kriss/Dev/scm/scm.vilanet.fr/kriss/mcp-spotify
.venv/bin/python -c "import spotify_client; print('OK')"
```

Expected: `OK`

---

### Task 2: Add `id` field and BPM enrichment to `get_playlist_tracks`

**Files:**
- Modify: `spotify_client.py:get_playlist_tracks`

- [ ] **Step 1: Add `"id"` to the track dict and call the helper**

In `get_playlist_tracks`, add `"id": track["id"],` to the `results.append({...})` block (alongside `"uri"`), and add `_enrich_with_bpm(sp, results)` just before the `return` statement:

```python
            results.append({
                "name": track["name"],
                "artists": [a["name"] for a in track["artists"]],
                "album": track["album"]["name"],
                "duration_ms": track["duration_ms"],
                "duration": _format_duration(track["duration_ms"]),
                "popularity": track.get("popularity"),
                "id": track["id"],
                "uri": track["uri"],
                "added_at": item["added_at"],
            })
        page += 1
        response = sp.next(response) if response["next"] else None
    _enrich_with_bpm(sp, results)
    _dbg(f"get_playlist_tracks returning {len(results)} tracks")
    return results
```

- [ ] **Step 2: Smoke test**

```bash
SPOTIPY_CLIENT_ID=d66baed203d1461a860acbc5db27e3f5 \
SPOTIPY_CLIENT_SECRET=6d9ccf95957749ffac433919b585f4ff \
SPOTIPY_REDIRECT_URI=http://127.0.0.1:8888/callback \
.venv/bin/python -c "
import spotify_client, json
tracks = spotify_client.get_playlist_tracks('7LhqpCM88rPqDqxTLadLmf')
for t in tracks[:3]:
    print(t['name'], '|', t.get('bpm'), 'bpm')
" 2>/dev/null
```

Expected: 3 lines like `oh baby | 128.0 bpm`

---

### Task 3: Add `id` field and BPM enrichment to `list_saved_tracks`

**Files:**
- Modify: `spotify_client.py:list_saved_tracks`

- [ ] **Step 1: Add `"id"` to the track dict and call the helper**

In `list_saved_tracks`, add `"id": track["id"],` to the `results.append({...})` block, and add `_enrich_with_bpm(sp, results)` just before the `return` statement:

```python
            results.append({
                "name": track["name"],
                "artists": [a["name"] for a in track["artists"]],
                "album": track["album"]["name"],
                "duration_ms": track["duration_ms"],
                "duration": _format_duration(track["duration_ms"]),
                "popularity": track["popularity"],
                "id": track["id"],
                "uri": track["uri"],
                "added_at": item["added_at"],
            })
    _enrich_with_bpm(sp, results)
    return results
```

- [ ] **Step 2: Smoke test**

```bash
SPOTIPY_CLIENT_ID=d66baed203d1461a860acbc5db27e3f5 \
SPOTIPY_CLIENT_SECRET=6d9ccf95957749ffac433919b585f4ff \
SPOTIPY_REDIRECT_URI=http://127.0.0.1:8888/callback \
.venv/bin/python -c "
import spotify_client
tracks = spotify_client.list_saved_tracks(limit=3)
for t in tracks:
    print(t['name'], '|', t.get('bpm'), 'bpm')
" 2>/dev/null
```

Expected: 3 lines with bpm values.

---

### Task 4: Add `id` field and BPM enrichment to `search_tracks`

**Files:**
- Modify: `spotify_client.py:search_tracks`

- [ ] **Step 1: Add `"id"` to the track dict and call the helper**

In `search_tracks`, add `"id": track["id"],` to the `results.append({...})` block, and add `_enrich_with_bpm(sp, results)` just before the `return` statement:

```python
    for track in response["tracks"]["items"]:
        results.append({
            "name": track["name"],
            "artists": [a["name"] for a in track["artists"]],
            "album": track["album"]["name"],
            "duration_ms": track["duration_ms"],
            "duration": _format_duration(track["duration_ms"]),
            "popularity": track["popularity"],
            "id": track["id"],
            "uri": track["uri"],
        })
    _enrich_with_bpm(sp, results)
    return results
```

- [ ] **Step 2: Smoke test**

```bash
SPOTIPY_CLIENT_ID=d66baed203d1461a860acbc5db27e3f5 \
SPOTIPY_CLIENT_SECRET=6d9ccf95957749ffac433919b585f4ff \
SPOTIPY_REDIRECT_URI=http://127.0.0.1:8888/callback \
.venv/bin/python -c "
import spotify_client
tracks = spotify_client.search_tracks('LCD Soundsystem', limit=3)
for t in tracks:
    print(t['name'], '|', t.get('bpm'), 'bpm')
" 2>/dev/null
```

Expected: 3 lines with bpm values.

---

### Task 5: Commit

- [ ] **Commit all changes**

```bash
git add spotify_client.py
git commit -m "feat: add bpm field to all track-returning tools via audio-features endpoint"
```