A dear reader makes it crystal clear

It's funny, the mental blocks that prevent you from seeing something, even when it's staring you right in the face.

A devoted reader explains:

Accept a mid-October full of hail (5,2)

• Accept: The definition, not part of the cryptic.
• a mid-October full of hail: the cryptic clue.

The cryptic clue is then de-crypted, as follows:

• a: The letter a, part of the solution.
• mid-October: The letter o, part of the solution.
• full of: The words that says it's a container cryptic (we're going to rearrange the parts to put some letters inside of other letters)
• hail: The word greet, part of the solution.

So you have:

a     o, full of greet,
• or: a greet o
• which is: agree to

Answer is agree to

Many thanks to my faithful correspondent!