36 CFR § 800.14(b)(4)
The ACHP can designate an agreement document as a prototype that can be used for the same type of program or undertaking in more than one program or area. When a federal agency uses a prototype programmatic agreement, the agency may develop and execute the agreement with the appropriate SHPO/THPO without the need for the ACHP's participation in consultation or ACHP signature.
The benefits of a prototype agreement include expediting review of routine activities with limited potential to affect historic properties; providing predictability in the treatment of historic properties through the use of a template agreement; and allowing the federal agency and SHPO/THPO to execute such agreements without ACHP involvement. Once a prototype agreement is designated by the ACHP, agencies can use it exactly as approved for subsequent agreements with individual SHPOs/THPOs or modify the language to meet their particular needs so long as they stay within the broad parameters established by the ACHP for the prototype agreement.
More information is available in the Prototype Programmatic Agreement Guidance.