diff --git a/README.md b/README.md
new file mode 100644
index 0000000..500ec48
--- /dev/null
+++ b/README.md
@@ -0,0 +1,20 @@
+# Cleantoots
+
+## Initial config
+
+Only once
+
+```bash
+pipenv install
+pipenv run python main.py create-app
+pipenv run python main.py get-credentials
+```
+
+## Run
+
+See `config.py` for options.
+
+```bash
+pipenv run python main.py clean-toots  # Defaults to a dry run. Does NOT delete.
+pipenv run python main.py clean-toots --delete  # Delete without prompt.
+```
diff --git a/config.py b/config.py
index cbc44d9..2daf287 100644
--- a/config.py
+++ b/config.py
@@ -1,12 +1,21 @@
-USER_SECRET_FILE = "cleantootsuser.secret"
+# A file to store app information obtained when running `create-app`
 APP_SECRET_FILE = "cleantootsapp.secret"
+# A file to store the user secrets obtained when running `get-credentials`
+USER_SECRET_FILE = "cleantootsuser.secret"
+# Your Mastodon server URL
 API_BASE_URL = "https://fosstodon.org"
+
+# IDs of toots you want to protect (never delete)
 PROTECTED_TOOTS = [
     103361883565013391,
     103362008817616000,
     103363106195441418,
 ]
+# Toots that have at least this number of boosts won't be deleted.
 BOOST_LIMIT = 5
+# Toots that have at least this number of favorites won't be deleted.
 FAVORITE_LIMIT = 5
+# Toots that are more recent than this number of days won't be deleted.
 DAYS_COUNT = 30
+# The timezone to use for dates comparisons.
 TIMEZONE = "Europe/Paris"