Ankiconnect will not add note - anki

Question

I am trying to use Ankconnect to add a note, the deck and the model exists and the fields are correct, but I just get "null" back (and the card is not added).
Running this bash script
echo "---------- The deck exists:"
curl localhost:8765 -X POST -d '{
"action": "getDeckConfig",
"version": 6,
"params": {
"deck": "Foo"
}
}'
echo "---------- The model exists:"
curl localhost:8765 -X POST -d '{
"action": "modelFieldNames",
"version": 6,
"params": {
"modelName": "Auto-generated"
}
}'
echo "---------- But adding a card fails:"
curl localhost:8765 -X POST -d '{
"action": "addNotes",
"version": 6,
"params": {
"notes": {
"deckName": "Foo",
"modelName": "Auto-generated",
"fields": {
"Question": "why?",
"Answer": "because!",
"Card ID": "foo"
},
"options": {
"allowDuplicate": true
},
}
}
}'
Produces these results
---------- The deck exists:
{"result": {"dyn": false, "usn": 82, "timer": 0, "replayq": true, "name": "Default", "id": 1, "lapse": {"mult": 0.0, "minInt": 1, "delays": [10], "leechAction": 0, "leechFails": 8}, "autoplay": true, "rev": {"hardFactor": 1.2, "ivlFct": 1.0, "ease4": 1.3, "perDay": 200, "fuzz": 0.05, "minSpace": 1, "bury": false, "maxIvl": 36500}, "mod": 1560476298, "maxTaken": 60, "new": {"ints": [1, 4, 7], "perDay": 20, "delays": [1, 10], "order": 1, "initialFactor": 2500, "bury": false, "separate": true, "LBGIMinBefore": 1, "LBGIMinAfter": 1, "LBEIMinBefore": 4, "LBEIMinAfter": 4}}, "error": null}
---------- The model exists:
{"result": ["Question", "Answer", "Card ID"], "error": null}
---------- But adding a card fails:
null

Answer 1

There's a few errors in your JSON.
Add "tags": [] to each of your notes objects, as it seems to be mandatory from the tests I've done but can be empty.
This will at least get you an output of {"result": [null, null, null, null, null], "error": null}
But then you need to fix some of your fields
"addNotes" takes an array of "notes" objects, but you're assigning a single object to "notes" and not an array.
"modelName" cannot be "Auto-generated" change it to "Basic"
"Question" should be "Front"
"Answer" should be "Back"
So this is what the object in your curl call should look like:
{
"action": "addNotes",
"version": 6,
"params": {
"notes": [
{
"deckName": "Foo",
"modelName": "Basic",
"fields": {
"Front": "why?",
"Back": "because!",
"Card ID": "foo"
},
"options": {
"allowDuplicate": true
},
"tags": []
}
]
}
}