Ideas discussed are general, do they still fall under a signed NDA/NC?
<p>A lets B sign a Non-Disclosure Agreement/Non-Compete ("NDA/NC") and then shares its ideas.</p>

<p>How "broad"/"general" can these ideas be to not be considered confidential?
E.g. the idea that A tells B is this: "Making an app similar to <em>x</em> but with a better UX and simpler design." without getting into details, <strong>how</strong> it can be done more intuitive/simpler.</p>

<p>Can this idea be protected by the NDA/NC without any details about <em>how</em> you could reach this goal?</p>

<p>NDA provisions in general are rather similar. In particular the ones covering the exceptions to the confidentiality obligations required to the receiving party.
Such provisions normally have the following wording (more or less):
Information shall not be treated as Confidential if:
- at the time of disclosure is already in the public domain or becomes available to the public w/o breach by receiving party;
- the receiving party receives it from a third party free to lawfully disclose such information;
- was in the prior lawfull possession of the receiving party;
- was independently developed by the receiving party; 
- is approved to be released by the disclosing party; or 
- the receiving party is required by law to disclose in response to a valid order of a court or by a government agency.</p>

<p>Your particular case might not necessarily fall under any of this exceptions (i do not know the exact wording of the NDA you're referring to) but in any case, please note that simply telling a third party that you are discussing the development of "an app similar to x but with a better UX and simpler design", might already be considered as a breach of confidentiality.
Surely the NDA is identified as being Confidential itself and it probably also contains a section saying something like: "This Agreement and its contents shall be treated as Confidential Information".</p>

contract-law patents non-compete