Argthtjtr

We are working in teams on the same files. We developed a mechanism to add markers for oneself or to address other people with the following syntax (similar to the @ addressing mechanism here at the StackExchange networks):

//Bob: I need to remember this place and come back later (addressed oneself)

//Bob @ Alice: Please continue here or please fix this error

With the words of 1006a:

So to put this in English, you currently have a notation that means
something like

Bob says to Alice: ...

but you want something that can be read:

Alice, Bob says: ...?

In the tools we use there is a special view where everybody can see this "note". However for a better ordering we need to switch both names but want to keep the meaning. Is there an opposite symbol for the @ (at) sign? I didn't find any so a short word would also suffice. But all the words I can think of don't exactly match the meaning.

// Alice (by Bob): Please continue here or please fix this error

// Alice (from Bob): Please continue here or please fix this error

// Alice (addressed by Bob): Please continue here or please fix this error

The first two sound strange and the last one is too clumsy - isn't there a short version or an @ antonym symbol?
Unfortunately a leading @ (e.g. //@Alice (by Bob) ...) is not allowed since that would throw off the ordering. So the addressee name needs to come first.

The caret (^) is sometimes used for a similar purpose, to identify the author of a tweet.

Mashable said in 2013: "The caret, or hat sign, is used to denote a tweet composed and sent by an individual on behalf of a group account used by multiple people (often a company or organization) account. It usually appears at the end of a Tweet and precedes initials, to indicate which user sent the tweet (e.g., ^JS)." Wikipedia calls this a "Signature tag" (in the Caret article): "a caret placed before a word is used to tag that word as an individual's signature".

Some people say the caret is used because it looks like a hat, and hence in the sense of hat tip (used to acknowledge a source), but I don't know if this is a folk etymology.

The @tention, in some cases, @ is used for "attention" in email messages originally sent to someone else or @mention symbol is a well known universal concept, there is little need to not draw attention to oneself, however it's not uncommon in such context to bracket [oneself] as editor or even embrace {yourself} pun intended [KJO]

// Alice: you could try this [Bob SquarePants]

Such usage may depend on other syntax clashes. The hashtag was intended to use CamelCase as in this first case

If case acceptable
// Alice:#BobSquarepants Shall I exchange the stack here.

Else

// Alice:Bob=Did * you exchange the stack here.

Else

// Alice<Bob: I suggest you exchange stack here.

End case

• equally note I have used the = same as in triple tag structure

Your project is using the at symbol in a different way than Stack Exchange and social media; a more mainstream way would be

//Bob: @Alice Please continue here or please fix this error

Note the lack of a space after the @ sign, and the fact that it's part of the message, not the header. Your symbolism could be interpreted as Bob directing a message 'at' Alice. But I doubt that there's a commonly accepted antonym for this.

What you could do is replace the @ symbol with something else that represents addressing, e.g. → (or -> if it needs to be ASCII). It's very easy to see what the antonym of that symbol would be.