I was present at Eid with ‘Umar, and he started with the prayer before the khutbah. He said: The Messenger of Allah ﷺ forbade fasting on these two days. The day of al-Fitr is the day when you break your fast, and on the day of al-Adha, eat the meat of your sacrifices. (Using translation from Aḥmad 163)
شَهِدْتُ الْعِيدَ مَعَ عُمَرَ ؓ فَبَدَأَ بِالصَّلَاةِ قَبْلَ الْخُطْبَةِ ثُمَّ قَالَ إِنَّ رَسُولَ اللهِ ﷺ نَهَى عَنْ صِيَامِ هَذَيْنِ الْيَوْمَيْنِ أَمَّا يَوْمُ الْأَضْحَى فَتَأْكُلُونَ مِنْ نُسُكِكُمْ وَأَمَّا يَوْمُ الْفِطْرِ فَفِطْرُكُمْ مِنْ صِيَامِكُمْ