diff --git a/src/command/config.rs b/src/command/config.rs
index 76d60ee..0c9974a 100644
--- a/src/command/config.rs
+++ b/src/command/config.rs
@@ -16,8 +16,9 @@ pub(crate) enum Commands {
     Validate,
 }
 
+/// Errors that can happen in `config` subcommand
 #[derive(thiserror::Error, Debug)]
-pub(crate) enum Error {
+pub(crate) enum ConfigError {
     #[error(transparent)]
     Update(#[from] update::UpdateError),
     #[error(transparent)]
@@ -89,7 +90,7 @@ fn next_revision() -> Result<Option<Revision>, RevisionCheckError> {
     Ok(next_revision)
 }
 
-pub(crate) async fn run(command: Commands) -> Result<(), Error> {
+pub(crate) async fn run(command: Commands) -> Result<(), ConfigError> {
     match command {
         Commands::Update { revision } => update::run(revision).await?,
         Commands::Validate => validate::run()?,
diff --git a/src/command/config/update.rs b/src/command/config/update.rs
index 2fcec09..802d65e 100644
--- a/src/command/config/update.rs
+++ b/src/command/config/update.rs
@@ -10,6 +10,7 @@ use chrono::Local;
 use color_print::cprintln;
 use std::{fs, io};
 
+/// Errors that happen in `config update` subcommand
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum UpdateError {
     #[error(transparent)]
diff --git a/src/command/config/update/v1.rs b/src/command/config/update/v1.rs
index d208184..fbe5eb2 100644
--- a/src/command/config/update/v1.rs
+++ b/src/command/config/update/v1.rs
@@ -15,6 +15,7 @@ use std::{
 use url::Url;
 use yaml_rust::{Yaml, YamlLoader};
 
+/// Errors that can happen in `config update v1` subcommand
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum Error {
     #[error("failed to parse the old config file ({})", OLD_CONFIG_PATH)]
@@ -29,6 +30,7 @@ pub(crate) enum Error {
     InvalidUrl(#[from] url::ParseError),
 }
 
+/// Errors that can happen while reading `.config/default.yml`
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum ReadYamlConfigError {
     #[error(transparent)]
@@ -39,6 +41,7 @@ pub(crate) enum ReadYamlConfigError {
     InvalidConfig(String),
 }
 
+/// Errors that can happen while writing `config/{server,client}.toml`
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum WriteTomlConfigError {
     #[error("failed to serialize the new server config into TOML format")]
diff --git a/src/command/config/validate.rs b/src/command/config/validate.rs
index 0db2da5..5336bec 100644
--- a/src/command/config/validate.rs
+++ b/src/command/config/validate.rs
@@ -8,6 +8,7 @@ use color_print::cprintln;
 use std::{fs, io::Read};
 use validator::Validate;
 
+/// Errors that can happen in `config validate` subcommand
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum ValidationError {
     #[error(transparent)]
diff --git a/src/command/mod.rs b/src/command/mod.rs
index a88ec00..65a867e 100644
--- a/src/command/mod.rs
+++ b/src/command/mod.rs
@@ -5,10 +5,11 @@ mod version;
 
 use clap::{Parser, Subcommand};
 
+/// Errors that can happen in any commands
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum Error {
     #[error(transparent)]
-    Config(#[from] config::Error),
+    Config(#[from] config::ConfigError),
 }
 
 #[derive(Parser)]