Use the --timeout flag to change the timeout.
herbie shell --seed 2020210
(FPCore (alpha beta)
:name "Octave 3.8, jcobi/3"
:precision binary64
:pre (and (> alpha -1.0) (> beta -1.0))
(/ (/ (/ (+ (+ (+ alpha beta) (* beta alpha)) 1.0) (+ (+ alpha beta) (* 2.0 1.0))) (+ (+ alpha beta) (* 2.0 1.0))) (+ (+ (+ alpha beta) (* 2.0 1.0)) 1.0)))