However, letters or documents prepared by attorneys which memorialize the terms of the agreement reached will suffice.' [Cit.]" Stevens v. McCarty, 198 Ga. App. 412, 413 (1), 414 ( 401 S.E.2d 605). As a preliminary matter, we must decide whether a plaintiff's "offer to settle" an existing lawsuit for his personal injuries "for the limits of liability coverage" is an offer capable of acceptance. "`"(I)f the offer is in any case so indefinite as to make it impossible for a court to decide just what it means, and to fix the legal liability of the parties, its acceptance can not result in an enforceable agreement.
" Dickey v. Harden, 202 Ga. App. 645, 647 ( 414 S.E.2d 924) (1992). Despite plaintiffs' argument to the contrary, an attorney may bind his clients outside the context of formal litigation and this may be done by letter agreement, as here. Stevens v. McCarty, 198 Ga. App. 412, 414 (1) ( 401 S.E.2d 605) (1991); see generally Brumbelow v. Northern Propane Gas Co., 251 Ga. 674 ( 308 S.E.2d 544) (1983). Therefore, summary judgment as to Garner White and Garner White Enterprises, Inc. was appropriate on this ground and makes consideration of the remaining enumerations unnecessary as to these two defendants.