+ ``--keep``
+ Keep the message file if indexing fails, and keep the message
+ indexed if applying tags or maildir flag synchronization
+ fails. Ignore these errors and return exit status 0 to
+ indicate successful mail delivery.
+
+ ``--no-hooks``
+ Prevent hooks from being run.
+
+ ``--decrypt=(true|false)``
+
+ If true and the message is encrypted, try to decrypt the
+ message while indexing. If decryption is successful, index
+ the cleartext itself. Either way, the message is always
+ stored to disk in its original form (ciphertext). Be aware
+ that the index is likely sufficient to reconstruct the
+ cleartext of the message itself, so please ensure that the
+ notmuch message index is adequately protected. DO NOT USE
+ ``--decrypt=true`` without considering the security of
+ your index.
+
+ See also ``index.decrypt`` in **notmuch-config(1)**.
+