Seems like Trump announced a ceasefire before many Israeli and Iranian government officials knew about the talks or agreement. There was a period between the announcement of a ceasefire and the time it went into effect when Israel and Iran struck each other while they still could. The ceasefire appears to have been broken, but may be holding now.
Claims that the Iranian nuclear program was obliterated sound like silly propagandistic lies by the Trump administration. The nuclear program was greatly damaged, but not obliterated, and Iran can rebuild. Depending on how fast Iran can rebuild, this may have ultimately been a futile attack that only makes Iran more determined to get a nuclear weapon.