Provider capabilities

Capabilities are declared per connection: identity, catalog, playlistRead, playlistWrite, library, playback, and history. The same provider may have multiple connections with different availability.

Reads may use the configured preferred connection and permitted fallback rules. Writes resolve exactly one available connection with the requested capability. If no target is available, or more than one target is possible without an explicit selection, the operation fails closed. JamRelay never silently writes to another provider or account.

Tracks are represented internally as canonical entities with provider mappings. Provider IDs and URLs remain provider-specific evidence; they are not universal identifiers. Cross-provider transfer therefore plans a match and exposes confidence/ambiguity before any destination write.

Playlist operation capabilities

In addition to the legacy high-level playlistRead and playlistWrite booleans, provider connections expose granular playlist operations: create, add, remove, reorder, replace, and update. Generic writes check the exact operation before provider I/O. For example, YouTube supports playlist item insertion, deletion, reordering, and metadata updates, but does not advertise replace; a generic replace request fails closed.