The Messenger of Allah ﷺ would fast until we said he did not intend to break his fast, and he would go without fasting until we said he did not intend to fast.
أخبرنا محمد بن النضر بن مساور المروزي قال حدثنا حماد عن مروان أبي لبابة
كان رسول الله ﷺ يصوم حتى نقول ما يريد أن يفطر ويفطر حتى نقول ما يريد أن يصوم
[Its chain is hasan]. Related by Tirmidhi, chapters on the merits of the Quran, chapter on reciting Surah Banu Israil and Surah Zumar before sleeping, no. 2920, 3405, from the hadith of Hammad bin Zayd, with this wording, and he said, hasan gharib... It is also found in Al-Kubra, no. 2656, and Ibn Khuzayma graded it sahih, no. 1163.