I'm surprised that we've heard from some very experienced people here - the people I'd like to hear from - and all we've really gotten is opinions. Isn't there a rule to be cited? Is this really an unresolved issue? My take on it is that it's generally accepted that "I'm going to put you all in" is not an actual bet. Clearly some people want to infer intention and make it so. Personally I don't think we can do that. I may have to spend some time reading rules.
I haven't found a clear cut rule, closest is RROP on poker etiquette:
POKER ETIQUETTE
The following actions are improper, and grounds for warning, suspending, or barring a violator:
.....
"Making statements or taking action that could unfairly influence the course of play, whether or not the offender is involved in the pot"
Otherwise, you're piecing different sections together:
GLOSSARY
ACTION: A fold, check, call, bet, or raise. For certain situations, doing something formally connected with the game that conveys information about your hand may also be considered as having taken action. Examples would be showing your cards at the end of the hand, or indicating the number of cards you are taking at draw.
BET: (1) The act of making a wager before anyone else on a betting round. (2)The chips used by a player to bet, call, or raise.
BETTING AND RAISING
9. A verbal statement in turn denotes your action, is binding, and takes precedence over a differing physical action.
I'm not finding anything that states you have verbally announce a particular number for the verbalization to constitute action. There are sections which note this but it's in reference only to string bets, which wouldn't apply here. With all of the above, the question comes down to whether or not you agree with what
@markleteenie posted:
"I will put you all in" is shortened way to say some variation of "I will [bet the amount that is the total of your current chip stack and thus will] put you all in [if you want to continue in this current hand]."