Vocalists should already be written as performers.
at least in the release I posted, it is not present
1 I Got My Eyes on You
recorded in: Chicago, Illinois, United States (on 1960-03-02)
baritone saxophone: Donald Hankins (Saxophonist) (on 1960-03-02)
bass: Jack Myers (US blues bassist) (on 1960-03-02)
drums (drum set): Fred Below (on 1960-03-02)
guitar: Buddy Guy (on 1960-03-02)
piano: Little Brother Montgomery (on 1960-03-02)
tenor saxophone: Jarrett Gibson (Blues tenor saxophonist) (on 1960-03-02) and Bob Neely (on 1960-03-02)
vocals: Buddy Guy (on 1960-03-02)
phonographic copyright (℗) by: MCA Records, Inc. (do not use as a release label! a division of UMG Recordings, Inc.) (in 1960)
recording of: I've Got My Eyes On You (on 1960-03-02)
writer: B. Guy and W. Dixon
publisher: Arc Music (U.S. rock & blues publisher), Arc Music Corporation (U.S. rock & blues publisher), Hoochie Coochie Music and Tristan Music Ltd.
And the tag performer have
Performer : Bob Neely (tenor saxophone); Buddy Guy (guitar); Donald Hankins (baritone saxophone); Fred Below (drums (drum set)); Jack Myers (bass); Jarrett Gibson (tenor saxophone); Little Brother Montgomery (piano)
That composer seems to come from a related work which this component has never considered before. I'll look in to it.
I hoped it will be possible, there is a lot of data in some releases that will be interesting to have available in tags