In partnership with the government of the Islamic Republic of Afghanistan (GIRoA) and the North Atlantic Treaty Organization (NATO), CSTC-A was charged with planning, programming, and implementing reform of the Afghan Security Forces consisting of the Afghan National Army (ANA) and the Afghan National Police (ANP) in order to develop a stable Afghanistan, strengthen the rule of law, and deter and defeat terrorism within its borders.

At its peak structure, CSTC-A/NTM-A was an 8,000-member advisor/mentor, combat theater forward-deployed strategic command recognized as an Army Corps-level Headquarters.

In November 2013, with NTM-A functionally aligned under International Security Assistance Force's Joint Command (IJC), NTM-A and CSTC-A disaggregated, allowing each organization to focus on its unique mission set.

Several months later, CSTC-A prepared Camp Eggers for turnover to the U.S. Department of State and transferred the unit's personnel and equipment to the Headquarters International Security Assistance Force (HQ ISAF) compound while simultaneously drawing down to Resolute Support mission numbers.

Along with the mission to budget, account, and execute more than $50 billion of Afghanistan Security Force Funds across multiple fiscal years, manage all foreign military sales for the Afghan National Defense Security Forces (ANDSF), and plan, budget, and execute all of the infrastructure projects in support of the ANDSF, DCOS SA/CSTC-A currently provides the TAA mission for four Essential Functions – EF1 (Plan, Program, Budget, and Execute), EF2 (Transparency, Accountability, and Oversight), EF3 (Rule of Law), and EF5 (Sustainment).