# Tags special to notmuch

This page describes the tags that the notmuch lib, cli, and emacs ui recognize
and treat specially.

## Tags special to lib

None of the tags recognized by the lib are configurable.

### Synchronization between tags and maildir flags

 - draft
 - flagged
 - passed
 - replied
 - unread
 - deleted (*)

The above tags are recognized by the lib, and synchronized with the
corresponding maildir flags through the following lib function calls:

 - `notmuch_message_maildir_flags_to_tags()`
 - `notmuch_message_tags_to_maildir_flags()`

The cli calls the above functions in "notmuch new" if the
maildir.synchronize_flags configuration option is enabled.

(*) The "deleted" tag is not synced to maildir T flag at the moment, but it may
be in the future.

### Automatic tags

 - attachment
 - signed
 - encrypted

The above tags are assigned to messages that have an attachment, or are signed
or encrypted, when adding a message to the database through the lib function
call:

 - `notmuch_database_add_message()`

The cli calls the above function in "notmuch new".

## Tags special to cli

All of the tags recognized by the cli are configurable.

### Default tags for new messages

 - unread
 - inbox
 - new (*)

These are the tags assigned to new message by default. The tags can be changed
using the new.tags configuration option.

(*) The "new" tag is by no means special or default, but it is documented here
as the typically used intermediate tag to use between "notmuch tag" and a
post-new tagging script.

### Default excluded tags

 - deleted
 - spam

These are the default tags used for excluding messages from search results. The
tags can be changed using the search.exclude_tags configuration option.

## Tags special to Emacs UI

Most of the tags recognized by the emacs ui are not (easily) configurable.

### Reading mail

 - unread
 - inbox

The elementary mail reading commands automatically remove the "unread" tag when
visiting a message, and remove the "inbox" tag when archiving a message.

### Other

 - replied
 - flagged
 - deleted (*)

The "replied" tag is added to messages that are replied to, and "flagged"
messages are highlighted through `notmuch-search-line-faces` by default.

(*) There are patches to tag, untag, and hide "deleted" tagged messages, but
they have not been merged at the time of writing this.