The most common and most likely answer to this crossword clue is the 5 plus 7 letter word SPELL CHECKER
I've seen this crossword clue in Independent
S
P
E
L
L
C
H
E
C
K
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Buddy explains!
The straight part
We know that "electronic tool" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case electronic tool = spell checker.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPELL CHECKER mean?
SPELL CHECKER noun- A software application that attempts to verify spelling in a document.