res = client.data_modeling.containers.retrieve(('mySpace', 'myContainer'))

from cognite.client.data_classes.data_modeling import ContainerId
res = client.data_modeling.containers.retrieve(ContainerId(space='mySpace', external_id='myContainer'))

{
  "items": [
    {
      "space": "<string>",
      "externalId": "<string>",
      "usedFor": "node",
      "createdTime": 1730204346000,
      "lastUpdatedTime": 1730204346000,
      "isGlobal": true,
      "properties": {},
      "name": "<string>",
      "description": "<string>",
      "constraints": {},
      "indexes": {}
    }
  ]
}