I also adore the capability that I have to flag articles from folks I follow on Twitter and save them to Instapaper.

This sentence has (at least) two readings, which are probably only obvious to a linguist (and who else would care?); I highlight the differences by adding commas:

1. I adore the capability, that I have to flag articles…
2. I adore the capability that I have, to flag articles…

In the first case you adore the capability. And the capability is that you have to do something (flag articles). Sounds rather odd, doesn’t it? The second case is more clear-cut and easy to understand: you can flag articles, and that’s the capability you have and adore.

So in terms of pattern grammar, you’re either looking at N that or N to-inf with capability. If you consult the Cobuild Dictionary, you’ll find that capability only occurs with the second pattern, the to-infinitive, so that you can rule out the first reading.

Another possibility would be to look at it in terms of modality: here we could argue that capability prospects a modality of ability, but have to expresses obligation; the two don’t go together. Hence the first reading sounds odd, as a capability does not usually force you to do anything, but rather enables you. It could, however, be used to signal sarcasm or irony, as in (the obviously made up) I really like that my new computer gives me the capability to have to save my work every five minutes. This is clearly an odd sentence, suggesting that modality works along similar lines as discourse prosody as described by Louw (1993) [for the full reference follow the previous link].

Here we have discussed two ways of disambiguating a sentence, one based on grammatical properties (or typical environments), and one on a non-syntactic phenomenon (modality). Pattern grammar allows us to identify what the typical usage would be, whereas modality explains to us why the first reading is at odds with the corresponding words. Now all we need is a ‘pattern grammar’ for modality!