What are the elements of conspiracy and common unlawful design?

The essential elements of conspiracy are: 1) an intention to agree, 2) the completion of an agreement, and 3) a common unlawful design: United States v. Dynar, 1997 CanLII 359 (SCC), [1997] 2 S.C.R. 462, [1997] S.C.J. No. 64, at para. 86. Further, there must exist an intention to put the common design into effect: O’Brien, at p. 668; Dynar at para. 86. The offence of conspiracy is entirely complete upon the formation of the agreement.