I have a .yaml file like this:

title: 'We'll do cool stuff'
draft: true

However, I get the following error:

Error parsing YAML: YAMLException: can not read a block mapping entry; 
a multiline key may not be an implicit key at line 2, column 6:

  draft: true
       ^

How can I fix it?

Note: this setup seems different than the other questions where this same error was raised, including the following posts:

You can use a site like YAML Formatter to format and validate your yaml:

yaml formatter example

In this case, the error message and location is a bit of red-herring.

The error is actually caused by a string that was accidentally terminated because of an unescaped quote symbol within the string. A hint for this is the syntax highlighting of <code>'<b><i>We</i></b>'ll do cool stuff'</code>.

To fix, in this case, you can just skip wrapping the string quotes and rewrite like this:

title: We'll do cool stuff
draft: true

Further Reading