- ``--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 succesful mail delivery.
+.. option:: --world-readable
+
+ When writing mail to the mailbox, allow it to be read by users
+ other than the current user. Note that this does not override
+ umask. By default, delivered mail is only readable by the current
+ user.
+
+.. option:: --decrypt=(true|nostash|auto|false)
+
+ If ``true`` and the message is encrypted, try to decrypt the
+ message while indexing, stashing any session keys discovered. If
+ ``auto``, and notmuch already knows about a session key for the
+ message, it will try decrypting using that session key but will
+ not try to access the user's secret keys. If decryption is
+ successful, index the cleartext itself. Either way, the message
+ is always stored to disk in its original form (ciphertext).
+
+ ``nostash`` is the same as ``true`` except that it will not stash
+ newly-discovered session keys in the database.
+
+ Be aware that the index is likely sufficient (and a stashed
+ session key is certainly 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`` or
+ ``--decrypt=nostash`` without considering the security of your
+ index.
+
+ See also ``index.decrypt`` in :any:`notmuch-config(1)`.