XF 2.2 Adding Tags to Existing Threads

[ChadCLund]

Using the API, what is the correct punctuation for adding tags to an existing thread?
The example:

REST API endpoints (2.2)

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xenforo.com

Does not show an example of how the tag array should be formed or expected

Currently, I have:
request1.AddParameter("add_tags", "[tag1,tag2,tag3]")

Does this need to be:
request1.AddParameter("add_tags", "[{tag1},{tag2},{tag3}]")
or
request1.AddParameter("add_tags", "[{'tag1'},{'tag2'},{'tag3'}]")

Please advise...