I use Visual Studio Code to edit the YAML files of my Home Assistant installation. Works great. However, there is one annoying thing: The YAML extension treats the “!secret” option of Home Assistant as “Syntax error” and underlines it in red.

To solve this problem, open your settings.json at
C:\Users\<yourusername>\AppData\Roaming\Code\User\settings.json
On my installation it looks like this:

After I added the code…
,
"yaml.customTags": [
"!secret scalar"
]
… it looked like this…

… and the problem is gone:
