to amend FCA complaints to cure a lack of particularity. See, e.g., United States ex rel. McCoy v. Calif. Med. Rev., Inc., 723 F.Supp. 1363, 1366 (N.D.Cal.1989). In this case, however, Karvelas never filed a motion to amend pursuant to Fed.R.Civ.P. 15(a), which provides for amendments as of right in the absence of a responsive pleading. Therefore, the only issue before us is whether the district court erred in failing sua sponte to provide Karvelas an opportunity to amend before dismissing his complaint with prejudice. Absent exceptional circumstances, a district court has no obligation to invite a plaintiff to amend his or her complaint when the plaintiff has not sought such amendment. See Emerito Estrada Rivera-Isuzu de P.R. Inc. v. Consumers Union, 233 F.3d 24, 30 (1st Cir.2000) (<HOLDING>)(emphasis in the original); see also Wagner v.
holding that because a claim was never raised in the district court this court would not consider it for the first time on appeal holding that district court did not commit error by failing to invite emerito to replead where despite its awareness that the defendant had called for dismissal for failure to state a claim based on deficient pleadings emerito never amended its complaint as of right  nor did it formally ask the district court after judgment to permit such an amendment holding that district court abused its discretion by denying plaintiffs motion to file fourth amended complaint holding that the district court abused its discretion by failing to award attorneys fees based on the objective unreasonableness of plaintiffs complaint holding that the district court did not abuse its discretion in dismissing a complaint with prejudice based on the plaintiffs failure to amend the complaint by the deadline imposed by the court