Joint FBI/CIA program to place willing FPCC members into Cuba to collect intelligence.
This was Lou de Santi's operation - probably why it was called AMSANTA. The program was initiated by the FBI as part of its effort targeting the FPCC as a subversive group and involved the CIA in briefing, debriefing and possibly monitoring travel of assets through Mexico City to and from Cuba. The program began in late 1962, had one major success in 1963 and appears to have been abruptly terminated in fall 63.
from the book: This project used FBI informants to develop intelligence on Cuba and the Castro regime. We know little about the overall project but in July 1963, one such asset used his FPCC [Fair Play for Cuba] connections to obtain a visa from the Cuban government and to travel illegally to and from Cuba (apparently from Mexico City on Cubana airlines).
Page 4 of this document describes the project: "Coverage of Castro Communist regime through use of existing Communist Party and front penetration assets. File was opened in December 1962."
"AMSANTA Project 19-6-73/3: Memo for the Record dated 10 July 1963 by Lou de Santi: Concerns FBI informant Victor Vicente, Puerto Rican citizen, who penetrated Communist parties in New York City, left New York for Cuba via Mexico as guest of ICAP (Cuban Peoples Friendship Institute). Was debriefed by CIA staffer Lou de Santi upon his return to the US in July-Aug 63. Vicente stated he had had interviews with Castro and Che Guevara. Vicente penetrated the FPCC, the Casa Cuba, and Jose Marti Club in New York City."