Contract Formation ke Liye Essential Intention Kaun Hoga?

Main socha tha ki jab contractor aur contractor milke ek deal banana chahte hain toh yeh essential intention donon ke beech me hoga hi. Lekin phir bhi kuch cases mein iska mean kya hota hai? Kya yeh kahi contract me mention hai, kahi nahi toh kaise pata chalta hai? Main Sunil Bharti ke case ko dekh raha hoon jaha pr yeh suna gaya hai ki essential intention sirf contractor mein hona chahiye. Lekin phir bhi yeh kaise thik hai ki kuch cases mein yeh dono party ke saath saath hona chahiye? Koi explanation please karein.