Pipe Symbol Error?

I'm trying my hand at writing Web Source Scripts, so if I have missed the documentation that answers my question, or if I'm doing something stupid and I've missed it, I apologize in advance.

In a script, I include the following lines:

outputto "COMMENT"
say "first | second"

I have debugging on, and within the log I see the lines:

Total output:
output["COMMENT"]= "first | second"

But from within the Tag Source / Adjust tag information dialog, the Comment field only has "First ". If I press OK, only "First " is written to the tag.

Is the pipe symbol a reserved keyword in the script engine? Do I just need to escape it somehow?

Thanks

PS - I tried escaping it "|", but either that is an incorrect escape, or that doesn't fix it.

It's a reserved char. I don't know if it can be escaped.

Thanks for the definitive info. Any chance you know where the documentation on the Web Source Framework is, other than https://docs.mp3tag.de/tag-sources - clear definitions on structure, reserved keywords, etc would be very helpful - more so than blindly going thru other posted scripts and figuring out what is an isn't correct.

afaik there's no further doc