diff --git a/tools/aconfig/aflags/src/load_protos.rs b/tools/aconfig/aflags/src/load_protos.rs
index 90d8599..f201d8f 100644
--- a/tools/aconfig/aflags/src/load_protos.rs
+++ b/tools/aconfig/aflags/src/load_protos.rs
@@ -60,3 +60,10 @@
     }
     Ok(result)
 }
+
+pub(crate) fn list_containers() -> Result<Vec<String>> {
+    Ok(aconfig_device_paths::parsed_flags_proto_paths()?
+        .into_iter()
+        .map(|p| infer_container(&p))
+        .collect())
+}
diff --git a/tools/aconfig/aflags/src/main.rs b/tools/aconfig/aflags/src/main.rs
index 07b7243..8173bc2 100644
--- a/tools/aconfig/aflags/src/main.rs
+++ b/tools/aconfig/aflags/src/main.rs
@@ -253,6 +253,14 @@
         FlagSourceType::DeviceConfig => DeviceConfigSource::list_flags()?,
         FlagSourceType::AconfigStorage => AconfigStorageSource::list_flags()?,
     };
+
+    if let Some(ref c) = container {
+        ensure!(
+            load_protos::list_containers()?.contains(c),
+            format!("container '{}' not found", &c)
+        );
+    }
+
     let flags = (Filter { container }).apply(&flags_unfiltered);
     let padding_info = PaddingInfo {
         longest_flag_col: flags.iter().map(|f| f.qualified_name().len()).max().unwrap_or(0),
@@ -298,7 +306,7 @@
         Command::List { container } => {
             if aconfig_flags::auto_generated::enable_only_new_storage() {
                 list(FlagSourceType::AconfigStorage, container)
-                    .map_err(|err| anyhow!("storage may not be enabled: {err}"))
+                    .map_err(|err| anyhow!("could not list flags: {err}"))
                     .map(Some)
             } else {
                 list(FlagSourceType::DeviceConfig, container).map(Some)