27 formalized on September 22, 2010, the prosecutor properly disclosed its terms and filed a discovery packet including all of the Commonwealth's documents. See Commonwealth v. Burgos, 462 Mass. 53, 62-63, cert. denied, 133 S. Ct. 796 (2012) (prosecutor informed defendant before trial of formalized cooperation agreements). Until the agreement was formalized, Colton received no promises, rewards, or inducements that the Commonwealth was obligated to disclose. With respect to the Commonwealth's delayed disclosure of a later statement Colton made about the DCF call, we disagree with the defendants that this statement was a critical change in his story. In his initial statement to the police, Colton did not provide specific information about the location from which the DCF telephone call was made, and, later, Colton asserted that William had made the call from Colton's home telephone. The defendants had adequate notice of this assertion in the Commonwealth's bill of particulars, a supplemental police report, and Colton's follow-up interview report. The information was provided long before trial, permitting ample time for the defense to weave it into its over-all strategy and counsel's cross-examination of Colton. See Commonwealth v. Baldwin, 385 Mass. 165, 175 (1982) ("disclosure was sufficiently timely to allow the defendant 'to make effective use of the