diff --git a/docs/rbtools/rbt/commands/attach.rst b/docs/rbtools/rbt/commands/attach.rst
index 2bf5d193a949c1703c2fa6c2d02efbadeea389b4..f92ddbae54d169f9227f09ca725063a11e247d99 100644
--- a/docs/rbtools/rbt/commands/attach.rst
+++ b/docs/rbtools/rbt/commands/attach.rst
@@ -10,4 +10,110 @@ The provided ``file`` will be attached to the review request matching
 
 
 .. rbt-command-usage::
+
+
+.. _rbt-attach-json:
+
+JSON Output
+===========
+
+.. versionadded:: 3.0
+
+When running with :option:`--json`, the results of the attachment will be
+outputted as JSON. This can be used by programs that wrap RBTools in order to
+automate attaching changes to review requests.
+
+
+Successful Payloads
+-------------------
+
+When attachment is successful, the results are in the form of:
+
+.. code-block:: javascript
+
+   {
+       "status": "success",
+
+       // Absolute path to the local attached file
+       "attached_file": "<string>",
+
+       // The ID of the attachment history record
+       "attachment_history_id": <int>,
+
+       // The provided or generated caption
+       "caption": "<string>",
+
+       // The filename recorded for the attachment
+       "filename": "<string>",
+
+       // The ID of the file attachment
+       "id": <int>,
+
+       // The stored mimetype of the attachment
+       "mimetype": "<string>",
+
+       // The ID of the review request
+       "review_request_id": <int>,
+
+       // The URL of the review request
+       "review_request_url": "<string>",
+
+       // The URL of the review UI for the attachment
+       "review_url": "<string>",
+
+       // The ID of the attachment revision
+       "revision": <int>
+   }
+
+For example:
+
+.. code-block:: console
+
+   $ rbt attach --json --caption "My Screenshot" 123 ./screenshot.png
+   {
+       "attached_file": "/home/user/src/project/screenshot.png",
+       "attachment_history_id": 132,
+       "caption": "My Screenshot",
+       "download_url": "https://example.com/media/uploaded/files/2022/03/17/94c05e13-de20-43e4-a0f8-bbb9b403af6f__screenshot.png",
+       "filename": "screenshot.png",
+       "id": 289,
+       "mimetype": "image/png",
+       "review_request_id": 123,
+       "review_request_url": "https://example.com/r/123/",
+       "review_url": "https://example.com/r/123/file/289/",
+       "revision": 1,
+       "status": "success"
+   }
+
+
+Error Payloads
+--------------
+
+When there's an error attaching a file, the results will be in the form of:
+
+.. code-block:: javascript
+
+   {
+       "status": "failed",
+
+       // A list of errors from the operation.
+       "errors": [
+           "<string>",
+           ...
+       ]
+   }
+
+For example:
+
+.. code-block:: console
+
+   $ rbt attach --json 123 ./screenshorts.png
+   {
+       "errors": [
+           "/home/user/src/project/screenshorts.png is not a valid file."
+       ],
+       "status": "failed"
+   }
+
+
 .. rbt-command-options::