The default filter set (if you don’t specify anything in the config) is:


The standard filter Configuration can be applied to these filters as well. Though note that most of the filters below set their own value for message, query and/or tags, and some ignore some of the standard settings.


The settings you can use are:

  • spam_tag = <tag>
  • Add <tag> to all mails recognized as spam.
  • The default is ‘spam’.
  • You may use it to tag your spam as ‘junk’, ‘scum’ or whatever suits your mood. Note that only a single tag is supported here.

Email will be considered spam if the header X-Spam-Flag is present.


This filter will tag messages based on what it has learnt from seeing how you’ve tagged messages in the past. See Classification for more details.


If the new message has been added to a thread that has already been tagged killed then add the killed tag to this message. This allows for ignoring all replies to a particular thread.


This filter looks for the List-Id header, and if it finds it, adds a tag lists and a tag named lists/<list-id>.


The settings you can use are:

  • sent_tag = <tag>
  • Add <tag> to all mails sent from one of your configured mail addresses.

  • The default is to add no tag, so you need to specify something.

  • You may e.g. use it to tag all mails sent by you as ‘sent’. This may make special sense in conjunction with a mail client that is able to not only search for threads but individual mails as well.

    More accurately, it looks for emails that are from one of your addresses and not to any of your addresses.

  • to_transforms = <transformation rules>
  • Transform To/Cc/Bcc e-mail addresses to tags according to the specified rules. <transformation rules> is a space separated list consisting of 'user_part@domain_part:tags’ style pairs. The colon separates the e-mail address to be transformed from tags it is to be transformed into. ‘:tags’ is optional and if empty, ‘user_part’ is used as tag. ‘tags’ can be a single tag or semi-colon separated list of tags.
  • It can be used for example to easily tag posts sent to mailing lists which at this stage don’t have List-Id field.


It extends SentMailsFilter with the following feature:

  • Emails filtered by this filter have the new tag removed, so will not have the inbox tag added by the InboxFilter.


This removes the new tag, and adds the inbox tag, to any message that isn’t killed or spam. (The new tags are set in your notmuch config, and default to just new.)


This filter adds tags to a message if the named header matches the regular expression given. The tags can be set, or based on the match. The settings you can use are:

  • header = <header_name>
  • pattern = <regex_pattern>
  • tags = <tag_list>

If you surround a tag with {} then it will be replaced with the named match.

Some examples are:

header = X-Spam-Flag
pattern = YES
tags = +spam

header = List-Id
pattern = <(?P<list_id>.*)>
tags = +lists;+{list_id}

header = X-Redmine-Project
pattern = (?P<project>.*)
tags = +redmine;+{project}

SpamFilter and ListMailsFilter are implemented using HeaderMatchingFilter, and are only slightly more complicated than the above examples.


This looks at which folder each email is in and uses that name as a tag for the email. So if you have a procmail or sieve set up that puts emails in folders for you, this might be useful.

  • folder_explicit_list = <folder list>
  • Tag mails with tag in <folder list> only. <folder list> is a space separated list, not enclosed in quotes or any other way.
  • Empty list means all folders (of course blacklist still applies).
  • The default is empty list.
  • You may use it e.g. to set tags only for specific folders like ‘Sent’.
  • folder_blacklist = <folder list>
  • Never tag mails with tag in <folder list>. <folder list> is a space separated list, not enclosed in quotes or any other way.
  • The default is to blacklist no folders.
  • You may use it e.g. to avoid mails being tagged as ‘INBOX’ when there is the more standard ‘inbox’ tag.
  • folder_transforms = <transformation rules>
  • Transform folder names according to the specified rules before tagging mails. <transformation rules> is a space separated list consisting of ‘folder:tag’ style pairs. The colon separates the name of the folder to be transformed from the tag it is to be transformed into.
  • The default is to transform to folder names.
  • You may use the rules e.g. to transform the name of your ‘Junk’ folder into your ‘spam’ tag or fix capitalization of your draft and sent folder:
folder transforms = Junk:spam Drafts:draft Sent:sent
  • maildir_separator = <sep>
  • Use <sep> to split your maildir hierarchy into individual tags.
  • The default is to split on ‘.’
  • If your maildir hierarchy is represented in the filesystem as collapsed dirs, <sep> is used to split it again before applying tags. If your maildir looks like this:

the mails in your afew folder will be tagged with ‘devel’ and ‘afew’.

If instead your hierarchy is split by a more conventional ‘/’ or any other divider


you need to configure that divider to have your mails properly tagged:

maildir_separator = /

Customizing filters

To customize these filters, there are basically two different possibilities:

Let’s say you like the SpamFilter, but it is way too polite

  1. Create an filter object and customize it
[SpamFilter.0] # note the index
message = meh

The index is required if you want to create a new SpamFilter in addition to the default one. If you need just one customized SpamFilter, you can drop the index and customize the default instance.

  1. Create a new type...
message = I hatez teh spam!

and create an object or two

message = Me hatez it too.

You can provide your own filter implementations too. You have to register your filters via entry points. See the afew for examples on how to register your filters. To add your filters, you just need to install your package in the context of the afew application.