The most common and most likely answer to this crossword clue is the 3 plus 2 plus 3 plus 3 letter word SPY IN THE CAB
I've seen this crossword clue in The Times
S
P
Y
I
N
T
H
E
C
A
B
Buddy explains!
The straight part
We know that "Recorder for something that’s often articulated informally" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case recorder for something that’s often articulated informally = spy in the cab.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.