Decline a meeting without damage

An invite you should not accept, from someone you cannot simply ignore.

Write a reply declining this meeting.

First pick the right move, and tell me which you chose and why:
- Decline outright, when I add nothing.
- Decline and delegate, when someone else should go.
- Decline and answer, when the meeting exists to extract information I can just send now.
- Ask for it to be shortened or made asynchronous.

Then write it:
- One line declining, with no elaborate excuse. Being busy is a complete reason and does not need dressing up.
- The substitute: the answer, the person, the document, or the written update.
- An offer to be looped in on the outcome, if I need to be.
- Under 60 words.

If this is a meeting I should actually attend, say so instead of helping me dodge it.

Invite:
My reason:

Declining and negotiating. Saying no cleanly, and putting a number or a counter-offer in writing.