Case
sendspin-go -> sendspin-js
Start the server first, then the client. The client advertises a listener, the server connects in, sends a metadata state update, disconnects, and the matrix compares a normalized metadata snapshot.
Server
sendspin-go
Client
sendspin-js
Status
Passed
Metadata snapshot matches
Inspection
Summaries, logs, and builds
Matrix result
RAW{
"case_dir": "artifacts/results/data/macos__server-initiated-metadata__sendspin-go__to__sendspin-js",
"client_exit_code": 0,
"client_impl": "sendspin-js",
"reason": "Metadata snapshot matches",
"scenario_id": "server-initiated-metadata",
"server_exit_code": 0,
"server_impl": "sendspin-go",
"status": "passed"
}Server summary (JSON)
RAW{
"client": {
"client_id": "sendspin-js-client-id",
"name": "sendspin-js-client",
"supported_roles": [
"player@v1",
"controller@v1",
"metadata@v1"
]
},
"discovery_method": "registry_advertised",
"implementation": "sendspin-go",
"initiator_role": "server",
"metadata": {
"expected": {
"album": "Protocol Fixtures",
"album_artist": "Sendspin",
"artist": "Sendspin Conformance",
"artwork_url": "https://example.invalid/almost-silent.jpg",
"progress": {
"playback_speed": 1000,
"track_duration": 180000,
"track_progress": 12000
},
"repeat": "all",
"shuffle": false,
"title": "Almost Silent",
"track": 1,
"year": 2026
}
},
"peer_hello": {
"payload": {
"client_id": "sendspin-js-client-id",
"device_info": {
"manufacturer": "Unknown",
"product_name": "Web Browser",
"software_version": "Node.js/22"
},
"name": "sendspin-js-client",
"player@v1_support": {
"buffer_capacity": 5242880,
"supported_commands": [
"volume",
"mute"
],
"supported_formats": [
{
"bit_depth": 16,
"channels": 2,
"codec": "pcm",
"sample_rate": 48000
},
{
"bit_depth": 16,
"channels": 2,
"codec": "pcm",
"sample_rate": 44100
}
]
},
"supported_roles": [
"player@v1",
"controller@v1",
"metadata@v1"
],
"version": 1
},
"type": "client/hello"
},
"preferred_codec": "none",
"role": "server",
"scenario_id": "server-initiated-metadata",
"server_id": "sendspin-go-server",
"server_name": "sendspin-go server",
"status": "ok"
}Server log
RAW{
"client": {
"client_id": "sendspin-js-client-id",
"name": "sendspin-js-client",
"supported_roles": [
"player@v1",
"controller@v1",
"metadata@v1"
]
},
"discovery_method": "registry_advertised",
"implementation": "sendspin-go",
"initiator_role": "server",
"metadata": {
"expected": {
"album": "Protocol Fixtures",
"album_artist": "Sendspin",
"artist": "Sendspin Conformance",
"artwork_url": "https://example.invalid/almost-silent.jpg",
"progress": {
"playback_speed": 1000,
"track_duration": 180000,
"track_progress": 12000
},
"repeat": "all",
"shuffle": false,
"title": "Almost Silent",
"track": 1,
"year": 2026
}
},
"peer_hello": {
"payload": {
"client_id": "sendspin-js-client-id",
"device_info": {
"manufacturer": "Unknown",
"product_name": "Web Browser",
"software_version": "Node.js/22"
},
"name": "sendspin-js-client",
"player@v1_support": {
"buffer_capacity": 5242880,
"supported_commands": [
"volume",
"mute"
],
"supported_formats": [
{
"bit_depth": 16,
"channels": 2,
"codec": "pcm",
"sample_rate": 48000
},
{
"bit_depth": 16,
"channels": 2,
"codec": "pcm",
"sample_rate": 44100
}
]
},
"supported_roles": [
"player@v1",
"controller@v1",
"metadata@v1"
],
"version": 1
},
"type": "client/hello"
},
"preferred_codec": "none",
"role": "server",
"scenario_id": "server-initiated-metadata",
"server_id": "sendspin-go-server",
"server_name": "sendspin-go server",
"status": "ok"
}
Client summary (JSON)
RAW{
"client_id": "sendspin-js-client-id",
"client_name": "sendspin-js-client",
"implementation": "sendspin-js",
"initiator_role": "server",
"metadata": {
"received": {
"album": "Protocol Fixtures",
"album_artist": "Sendspin",
"artist": "Sendspin Conformance",
"artwork_url": "https://example.invalid/almost-silent.jpg",
"progress": {
"playback_speed": 1000,
"track_duration": 180000,
"track_progress": 12000
},
"repeat": "all",
"shuffle": false,
"title": "Almost Silent",
"track": 1,
"year": 2026
},
"update_count": 1
},
"peer_hello": {
"payload": {
"active_roles": [
"metadata@v1"
],
"connection_reason": "playback",
"name": "sendspin-go server",
"server_id": "sendspin-go-server",
"version": 1
},
"type": "server/hello"
},
"preferred_codec": "none",
"role": "client",
"scenario_id": "server-initiated-metadata",
"server": {
"active_roles": [
"metadata@v1"
],
"connection_reason": "playback",
"name": "sendspin-go server",
"server_id": "sendspin-go-server",
"version": 1
},
"status": "ok"
}Client log
RAWSendspin: Adopted open WebSocket
Sendspin: Using player_id: sendspin-js-client-id
[Opus] Native decoder not available, falling back to FLAC/PCM
Sendspin: Connected to server
Sendspin: WebSocket disconnected
Sendspin: Connection closed
{
"status": "ok",
"implementation": "sendspin-js",
"role": "client",
"scenario_id": "server-initiated-metadata",
"initiator_role": "server",
"preferred_codec": "none",
"client_id": "sendspin-js-client-id",
"client_name": "sendspin-js-client",
"peer_hello": {
"type": "server/hello",
"payload": {
"server_id": "sendspin-go-server",
"name": "sendspin-go server",
"version": 1,
"active_roles": [
"metadata@v1"
],
"connection_reason": "playback"
}
},
"server": {
"server_id": "sendspin-go-server",
"name": "sendspin-go server",
"version": 1,
"active_roles": [
"metadata@v1"
],
"connection_reason": "playback"
},
"metadata": {
"update_count": 1,
"received": {
"title": "Almost Silent",
"artist": "Sendspin Conformance",
"album_artist": "Sendspin",
"album": "Protocol Fixtures",
"artwork_url": "https://example.invalid/almost-silent.jpg",
"year": 2026,
"track": 1,
"progress": {
"track_progress": 12000,
"track_duration": 180000,
"playback_speed": 1000
},
"repeat": "all",
"shuffle": false
}
}
}