diff --git a/.config/rash/rashrc.rkt b/.config/rash/rashrc.rkt
index 33b9427..92981b4 100644
--- a/.config/rash/rashrc.rkt
+++ b/.config/rash/rashrc.rkt
@@ -7,14 +7,15 @@
 (provide nv)
 
 (current-prompt-function
-  (λ (#:last-return-value retval)
+  (λ (#:last-return-value retval
+      #:last-command-duration duration)
     (unless (void? retval)
       (display ((current-rash-top-level-print-formatter) retval)))
 
     (parameterize ([current-environment-variables (environment-variables-copy (current-environment-variables))])
       (putenv "MZPROMPT_STATUS" (if (exn:fail? retval) "1" "0"))
       (putenv "MZPROMPT_FISH_MODE" "insert")
-      (putenv "MZPROMPT_DURATION" "0")
+      (putenv "MZPROMPT_DURATION" (number->string duration))
       (putenv "MZPROMPT_JOBS" "0")
       (readline-prompt #{prompt show |> port->bytes}))))