ORIGINAL: Capitaine
Nothing from my "source" but I did come across an actual Soviet archived top secret document, Document 103202/06, which became available after the fall of the USSR. This was signed by Marshall Timoshenko and the Chief of the Soviet General Staff at that time Merezkov. It outlines "Operation Thunderstorm" (or "Operatsia Groza") comprising the invasion of Europe slated for July 10, 1941. It was signed three months before Operation Barbarossa was signed.
It's mentioned in this Wikipedia entry here: https://en.wikipedia.org/wiki/Igor_Bunich
I think it's mentioned in that article that Stalin wasn't a military man but a statesman, and relied on others to implement his plans. Now, this looks concrete to me and with something like this in the offing you'd have to insist that nothing short of waiting till an actual Soviet invasion would provide proof of their intent if this doesn't convince you.
You are talking about MP-41 which was mobilization plan for year 41, not plan for invasion. True is that forces mobilized according to MP-41 were enormous and this rises question about purpose of such huge build up. Most obvious answer is attack on Germany.
Plans about Soviet attack on Germany were never revealed and never will(if exist).



