Completion Suggester with Exact Starting Match and Whitespace Separated Words

[foobarbaz]

Following the completion suggester example from here: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-suggesters-completion.html

Having trouble understanding how to index titles that have spaces. With the following index/mapping:

curl -XPUT 'localhost:9200/social?pretty' -H 'Content-Type: application/json' -d'
{
    "mappings": {
        "post" : {
            "properties" : {
                "suggest" : {
                    "type" : "completion"
                },
                "title" : {
                    "type": "keyword"
                }
            }
        }
    }
}
'

Adding a suggest with a space like so:

curl -XPOST 'localhost:9200/social/post' -H 'Content-Type: application/json'  '{"suggest":{"input":"Alec Baldwin","weight":4}}'

Produces the following error:

`{"error":{"root_cause":[{"type":"mapper_parsing_exception","reason":"failed to parse"}],"type":"mapper_parsing_exception","reason":"failed to parse","caused_by":{"type":"json_e_o_f_exception","reason":"Unexpected end-of-input in VALUE_STRING\n at [Source: org.elasticsearch.common.bytes.BytesReference$MarkSupportingStreamInputWrapper@691d96c0; line: 1, column: 51]"}},"status":400}curl: (3) [globbing] unmatched close brace/bracket in column 16`

If the space is turned into a dash:

curl -XPOST 'localhost:9200/social/post' -H 'Content-Type: application/json'  '{"suggest":{"input":"Alec-Baldwin","weight":4}}'

The suggest is successfully indexed:

{"_index":"social","_type":"post","_id":"AVtmxoQVIOBiOQZhZa8Y","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"created":true}

Have successfully indexed by splitting by space and indexing as an array like {"suggest":{"input":["Alec", "Baldwin"],"weight":4}} however when sending the completion suggester "Ale", this produces other matches like young alec baldwin which is undesired (these are programatically generated, too many to filter out manually); only interested in exact starting matches like Alec Baldwin or Alec Baldwin Jr.

Any insight would be greatly appreciated!

Best,
Joshua