Is Jesus' agony in Gethsemane recorded in all four Gospels?

No, the agony in Gethsemane is recorded in all three synoptic Gospels—Matthew, Mark, and Luke—but not in John's Gospel. John's Gospel focuses on His deity, while the synoptic Gospels emphasize His humanity and suffering, so this event is absent from John.

Les explains that Matthew, Mark, and Luke are called the synoptic Gospels and deal primarily with Jesus' humanity, while John's Gospel deals with His deity. Because of this distinction, many events covered in the synoptic Gospels are not mentioned in John. For example, the temptations are recorded in Matthew, Mark, and Luke but not in John. Likewise, the agony in the Garden of Gethsemane—and the intensity of that agony—is recorded in all three synoptic Gospels but is not recorded in John's Gospel, since it was part of His humanity and suffering.

Which Gospels include the description of Jesus' agony in Gethsemane, and which one does not?

All three of the first Gospels touch on many of these events, whereas John does not. Therefore, the first three Gospels include the description of Jesus' agony in Gethsemane, and John's Gospel omits it. This contrast highlights the differing Gospel accounts.