Docs
ECMA TR/53
ECMA Technical Report TR/53, plus ECMA 48 for the exact escape sequences are the only papers I could find about how BiDi in terminal emulators should work. I devote a separate chapter to them.
Arabeyes
Arabeyes is mentioned from PuTTY’s changelog. Doesn’t seem to be active nowadays.
Their ArabeyesTodo page says:
“Need an overall spec on how bidi/control-characters are to be handled within a terminal emulator (cursor movement, etc)”
Funny to see that apparently they went ahead and implemented something for PuTTY without any, and the bullet points for implementing it in other emulators also precede the bullet point of having a spec.