Q: At daily Mass, is the reader supposed to introduce the responsorial psalm the same as a reading: “Today’s Responsorial is Psalm 85. The response is….”?
A: Actually, no, though I hear many readers do it. The Order of Mass assigns introductions to the readings but not to the responsorials.
It probably has to do with the refrain, which is often not a direct quote from the psalm, but a tweaked quote. Not every word the people say comes directly from the bible.