How to get "usage guidance" for a tag from the Stack Exchange API?

Question

Stack Exchange site tags have "usage guidance", both a 1-paragraph "excerpt" and a longer tag description, as e.g. for JavaScript here. Is it possible to get this data through the API? The options listed under the "filter" menu on the API docs don't seem to include it.

Answer 1

You need the /tags/{tags}/wikis method for this. Here is a link to the documentation page, including the necessary parameters for the JavaScript tag. By default, the body of the tag wiki isn't returned, so you'll need a custom filter.

{
  "items": [
    {
      "excerpt_last_edit_date": 1570698075,
      "body_last_edit_date": 1573208252,
      "excerpt": "JavaScript (not to be confused with Java) is a high-level, dynamic, multi-paradigm, object-oriented, prototype-based, weakly-typed, and interpreted language used for both client-side and server-side scripting. Its primary use is in the rendering and manipulation of web pages. Use this tag for questions regarding ECMAScript and its various dialects/implementations (excluding ActionScript and Google-Apps-Script).",
      "body": "\n\n<p><strong><a href=\"https://en.wikipedia.org/wiki/JavaScript\" rel=\"nofollow noreferrer\">JavaScript</a></strong> (a dialect of ECMAScript) is a high-level, dynamic, multi-paradigm, object-oriented, <a href=\"https://en.wikipedia.org/wiki/Prototype-based_programming\" rel=\"nofollow noreferrer\">prototype-based</a>, weakly-typed, and interpreted language traditionally used for client-side scripting in web browsers.",
      "tag_name": "javascript"
    }
  ],
  "has_more": false,
  "quota_max": 10000,
  "quota_remaining": 9871
}

_{(note: I have omitted part of the body since otherwise this answer would be too long)}