diff --git a/README.md b/README.md
index 860b357..6fe1da1 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,5 @@
 # wev: run shell commands with environment variables
 
-**This is prerelease software. Don't use it. :)**
-
 `wev` is a command line tool for resolving environment variables then running shell commands.
 
 For example:
diff --git a/example.wev.yml b/example.wev.yml
new file mode 100644
index 0000000..729af5a
--- /dev/null
+++ b/example.wev.yml
@@ -0,0 +1,8 @@
+MY_NAME:
+  plugin:
+    id: wev-echo
+    value: Bobby Pringles
+
+[AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN]:
+  plugin:
+    id: wev-awsmfa
diff --git a/wev/mock_plugin.py b/wev/mock_plugin.py
index 5bf9bc8..949fe5d 100644
--- a/wev/mock_plugin.py
+++ b/wev/mock_plugin.py
@@ -18,6 +18,7 @@ class MockPlugin(PluginBase):
     `return_expires_at` will cause resolution to return an expiry date 60
     seconds in the future.
     """
+
     def __init__(
         self,
         values: dict,
diff --git a/wev/resolution_cache.py b/wev/resolution_cache.py
index ccfa87f..fdce4e6 100644
--- a/wev/resolution_cache.py
+++ b/wev/resolution_cache.py
@@ -56,12 +56,13 @@ def read_all(self) -> Dict[str, Dict[Tuple[str, ...], Dict[str, Any]]]:
         Raises `CacheReadError` if the cache cannot be read.
         """
         everything: Dict[str, Dict[Tuple[str, ...], Dict[str, Any]]] = {}
-        self.logger.debug("Reading cache: %s", self.path)
+        self.logger.debug("Reading entire cache: %s", self.path)
         try:
             with open(self.path, "r") as stream:
                 if content := stream.read().strip():
                     everything = YAML(typ="safe").load(content)
-                    self.logger.debug("Read cache: %s", everything)
+                    # Don't log the cache; it contains confidential information.
+                    self.logger.debug("Successfully read the entire cache.")
                 else:
                     self.logger.debug("Cache is empty: %s", self.path)
         except FileNotFoundError:
@@ -100,10 +101,11 @@ def save(self) -> None:
         self.logger.debug("Writing cache: %s", self.path)
         everything = self.read_all()
         everything[self.context] = self.resolutions
-        self.logger.debug("Saving entire cache: %s", everything)
+        # Don't log the cache; it contains confidential information.
+        self.logger.debug("Saving the entire cache: %s", self.path)
         with open(self.path, "w") as stream:
-            yaml = YAML(typ="safe")
-            yaml.dump(everything, stream)
+            YAML(typ="safe").dump(everything, stream)
+            self.logger.debug("Successfully saved the entire cache.")
 
     def update(self, names: Tuple, resolution: Resolution) -> None:
         """
@@ -113,5 +115,6 @@ def update(self, names: Tuple, resolution: Resolution) -> None:
             var_name:   Name of the environment variable.
             resolution: Resolution.
         """
-        self.logger.debug("Updating %s in cache: %s", names, resolution.store)
+        # Don't log the store; it's confidential.
+        self.logger.debug("Updating %s in cache.", names)
         self.resolutions[names] = resolution.store
diff --git a/wev/sdk/resolution.py b/wev/sdk/resolution.py
index 6d02941..a8110e4 100644
--- a/wev/sdk/resolution.py
+++ b/wev/sdk/resolution.py
@@ -9,9 +9,15 @@
 class Resolution:
     def __init__(self, store: Dict[str, Any]) -> None:
         self.logger = get_logger()
-        self.logger.debug("Resolution: store=%s", store)
+
+        # Don't log the store; it probably contains confidential information.
+        self.logger.debug("Initialising new Resolution.")
+
         if not isinstance(store, dict):
-            raise ValueError('"store" is not a dictionary: %s', type(store))
+            raise ValueError(
+                'Resolution "store" is not a dictionary: %s',
+                type(store),
+            )
         self.store = store
 
     def __eq__(self, other: Any) -> bool:
@@ -48,7 +54,9 @@ def make(
                 store.update({"values": value})
         if expires_at:
             store.update({"expires_at": expires_at.isoformat()})
-        get_logger().debug('"Resolution.make" created store: %s', store)
+
+        # Don't log the store; it contains confidential information.
+        get_logger().debug('"Resolution.make" created a new store.')
         return Resolution(store=store)
 
     @property
@@ -98,7 +106,8 @@ def time_until_expiry(self) -> str:
 
     @property
     def values(self) -> Tuple[str, ...]:
-        self.logger.debug("Reading the resolved value: %s", self.store)
+        # Don't log the store; it's confidential.
+        self.logger.debug("Reading the resolved value.")
         values = self.store.get("values", [])
         if isinstance(values, tuple):
             return values
diff --git a/wev/state/state.py b/wev/state/state.py
index 842c6bb..d825e4c 100644
--- a/wev/state/state.py
+++ b/wev/state/state.py
@@ -42,9 +42,9 @@ def get_variables(self) -> Iterator[Variable]:
                 store = self.config[key]
 
                 if cached_resolution := self.resolution_cache.get(names):
-                    self.logger.debug(
-                        "Adding cached resolution: %s", cached_resolution.store
-                    )
+                    # Don't log the resolution; the values are probably
+                    # confidential.
+                    self.logger.debug("Adding cached resolution.")
                     store.update({"resolution": cached_resolution.store})
 
                 yield Variable(names=names, store=store)
diff --git a/wev/variable.py b/wev/variable.py
index 1be0cad..7007f7a 100644
--- a/wev/variable.py
+++ b/wev/variable.py
@@ -11,11 +11,14 @@ class Variable:
 
     def __init__(self, names: Tuple[str, ...], store: Dict[str, Any]) -> None:
         self.logger = get_logger()
-        self.logger.debug('Variable: name="%s" values="%s"', names, store)
+
+        # Don't log the values; they're probably confidential.
+        self.logger.debug('Variable: name="%s"', names)
 
         if "resolution" in store and not isinstance(store["resolution"], dict):
             raise ValueError(
-                '"resolution" is not a dictionary: %s', type(store["resolution"])
+                '"resolution" is not a dictionary: %s',
+                type(store["resolution"]),
             )
 
         self.names = names