The phrase 'my only plan' is correct and usable in written English.
It can be used to express a single course of action that someone intends to pursue. For example, "I have spent weeks researching ways to save money on my next vacation, and my only plan is to drive instead of fly."
The question came at him again — "my only plan, at this time, is to run for re-election as attorney general," he answered — and again.
"My only plan is: I have no plan," he says.
My only plan was to stay true to my style.
My only plan toward the end was to try to capture the weirdness.
"My only plan this weekend is to watch football," said William J. Palatucci, a close confidante and adviser to Mr. Christie.
The future now seemed cavernous, and I didn't exactly have a Plan B, unless B stood for Baby: my only plan there was to request an epidural as soon as it was possible to receive one, and to hope for the best as I stumbled into first-time parenthood.
That gave me a bit of a taste for speed, but when I went out on the river this past week my only plans were to fish a little, travel a little, motor into a few neglected bays.
"My only research plan for the trip is to evaluate the differences between American and Russian engineering practices.
I can do almost no forward planning since I can only plan my art after I learn what the government is going to give me this year.
I greedily broke my sandwiches-only plan to take advantage of the great deal.
"My bipartisan proposal is the only plan that has a chance to be signed into law by the end of this year," says Bond. "So if the Democratic leaders are serious about protecting millions of auto-dependent jobs before the end of the year, they will embrace this approach".
