When the speaker really intends a particular object, there should be contextual evidence that lets the listener recover it. Merely noticing a transitive verb is insufficient to invent whichever object seems plausible.
Contrast:
«زَيْدٌ يَقْرَأُ» — In context this may describe Zayd's habit of reading.
«هَلْ قَرَأْتَ الْكِتَابَ؟ نَعَمْ، قَرَأْتُ» — “Did you read the book?” “Yes, I read [it].” Here the previous mention of the book provides an explicit clue.
The basic criterion is whether the intended proposition includes a recoverable object.