Spotify MCP: create_playlist tool creates playlists that never appear in user's library

Bug Description

The create_playlist tool appears to succeed — it returns a valid playlist URI and tracks are fetchable via fetch_tracks — but the created playlists never appear in the user's Spotify library (desktop app, mobile, or web player).

Steps to Reproduce

1. Connect Spotify integration in Claude desktop app
2. Ask Claude to create a playlist
3. create_playlist returns a valid playlist URI with GENERATIVE subtitle metadata
4. Check Spotify library (desktop, mobile, web player) — playlist is not there
5. Search for the playlist by name in Spotify — not found
6. Call fetch_tracks with the returned URI — tracks are returned successfully

Expected Behavior

The created playlist should appear in the authenticated user's Spotify library.

Actual Behavior

The playlist exists on Spotify's backend (tracks are fetchable) but is invisible in the user's library across all Spotify clients.

Environment

• Platform: macOS
• Claude Desktop App
• Spotify MCP (claude.ai Spotify)

Additional Context

• add_to_library works correctly — tracks saved via this tool appear in Liked Songs as expected
• get_currently_playing works correctly
• Only create_playlist is broken
• Multiple playlists were created across multiple sessions, none appeared in the user's library

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>