pyCardDAV is a simple to use CardDAV CLI client. It has built in support for
mutt's query_command but also works very well solo (and with other MUAs).

pyCardDAV consists of pycardsyncer, a program for syncing your CardDAV
resource into a local database and of pc_query, a program for querying the
local database.

Features:

  * Tested against davical, owncloud and sabredav
  * Import the sender's address directly from mutt
  * Add email addresses directly from mutt
  * Backup and import to and from .vcf files

WWW: http://lostpackets.de/pycarddav