A DESCRIPTION OF THE PROBLEM :
It looks like Skara's TagCommand creates a malformed Markdown link, see https://github.com/openjdk/skara/blob/c731445ce5dc110ad1967c8f6b1e7065a49c4f9e/bots/pr/src/main/java/org/openjdk/skara/bots/pr/TagCommand.java#L97
It appends a square bracket ']' instead of a parenthesis ')' after the `hashUrl`.
It looks like Skara's TagCommand creates a malformed Markdown link, see https://github.com/openjdk/skara/blob/c731445ce5dc110ad1967c8f6b1e7065a49c4f9e/bots/pr/src/main/java/org/openjdk/skara/bots/pr/TagCommand.java#L97
It appends a square bracket ']' instead of a parenthesis ')' after the `hashUrl`.