Has been closed as beeing off topic, given the reason that actually I recived many answers on something I wasn't looking for, so beeing unclear.
This has been clarryfied by Erik with his comment on one of my comments on one of the answers where I was complaining of he just tells me aspects but not how to achieve them. He commented:
"right, I understand. I think the question is misunderstood then. You're getting answers for GMPCs who WILL NOT drive the story forward, but it seems you are looking for a GMPC who CANNOT drive the story forward, even when directly asked to do so? – Erik Feb 17 at 11:17"
Which was pretty much on the point.
But I actually have no clue how to make it more clear, since from my point of view it is totally clear.
Since first of all in the title I'm asking for a character design that is supposed to not do. My intention here was metaplaying not beeing supposed, I was assuming this is clear, since I'm asking about a design and not how to play it that way. Is the title the problem and not clear enough?
The introducing backgroundstory why I'm asking this I told to avoid 2 things:
1st to make sure why I decided to handle it fits best this way for my given situation. So desputing answers that would recommend me avoid my problem by another gaming styl to avoid the GMPC.
2nd to make clear again its me who will have trouble in rollplaying it competent not having informations I as player actually have, while the character is trying to get the informations. So that every one understands I'm not looking for a design that makes the character independent from getting the information when rollplayed well, but I'm looking for a design that just makes an character willing to not share the informations even IF he would know about it, so it is working around my lack of rollplaying experience, and makes me stay in character by just saying "I won't tell you" without even exposing this is relevant information.
And finally the TL&DR part was set, so everyone who might have missunderstood my intention of the introduction(You know, I'm used to be missunderstood, so I'm planing allready what one might missunderstand and how I could avoid it eventually), just sees as standalone the question.
"How to design a character in a way, that his trait, behavior or background when roleplayed correctly lets him not participate in decision-making(footnote:Should the character be forced by another PC into making a decision, it is acceptable, since it is an exceptional case not caused by the GMPC's player himself.), while it still is obvious that his motivations are a success of the "party"?"
Here I'm finally off. I don't even have a clue why this was missunderstood.
I said the thing I'm asking for lets the character not participate1 and was even noting that the exceptional case of a situation where the character at least for given circumstances is able to participate, is aceptable. (AFAIK this would expresses that my given post by itself should express that this exception isn't even acceptable without the note).
So what exactly is in my OP flawed that I was by a handfull of people missunderstood? And how to fix it, so the post becomes on-topic?
1actually my impression is this was instead understood as only lets the character passively participate but again, no clue what makes the sentence sound like that?