The act of kavannah: Intending to Intend

(6) The sacrifice is slaughtered for the sake of six things:For the sake of the sacrifice, For the sake of the sacrificer, For the sake of the [Divine] Name, For the sake of fire-offerings, For the sake of fragrance, For the sake of pleasing; And a hatat and an asham for the sake of sin. Rabbi Yose said: even if one did not have any of these purposes in his heart, it is valid, because it is a regulation of the court. Since the intention is determined only by the worshipper.

...And also one who was passing behind a synagogue or if his house was next to the synagogue and he heard the sound of the shofar or of the megillah [being read], if he directed his heart (had intention), then he has fulfilled his obligation, but if not he has not fulfilled his obligation. Even though this one heard and this one heard, this one directed his heart and this one did not.

§ It is related that the following ruling was sent from Eretz Yisrael to Shmuel’s father: If one was forcibly compelled to eat matza on Passover, he has fulfilled his obligation. .... Rava said: That is to say that one who sounds a shofar for the music, having no intent to fulfill the mitzva, fulfills his obligation, since the critical issue is hearing the blast and not the intent of the blower.

(2) If one recited the Shema without a blessing, one has fulfilled the obligation of reciting the Shema. [Nonetheless,] one [later] goes back and recites the blessings without the Shema; however, it seems to me that it is proper to go back and recite the [entire] Shema with the blessings.

(4) There are those who hold that the commandments do not require intention, and there are those who hold that they do need intention in order to fulfill the doing of that commandment - and such [i.e. the latter] is the [correct] halacha.