diff --git a/cmd/joj3/stage/run.go b/cmd/joj3/stage/run.go
index daa71f9..e9d4fff 100644
--- a/cmd/joj3/stage/run.go
+++ b/cmd/joj3/stage/run.go
@@ -6,7 +6,7 @@ import (
 	"strings"
 
 	"github.com/joint-online-judge/JOJ3/cmd/joj3/conf"
-	executors "github.com/joint-online-judge/JOJ3/internal/executor"
+	"github.com/joint-online-judge/JOJ3/internal/executor"
 	_ "github.com/joint-online-judge/JOJ3/internal/parser"
 	"github.com/joint-online-judge/JOJ3/internal/stage"
 
@@ -139,7 +139,7 @@ func Run(
 ) (
 	stageResults []stage.StageResult, forceQuitStageName string, err error,
 ) {
-	executors.InitWithConf(
+	executor.InitWithConf(
 		conf.Stage.SandboxExecServer,
 		conf.Stage.SandboxToken,
 	)
diff --git a/internal/executor/all.go b/internal/executor/all.go
index 5c66365..a170328 100644
--- a/internal/executor/all.go
+++ b/internal/executor/all.go
@@ -1,4 +1,5 @@
-package executors
+// Package executor contains all the executors.
+package executor
 
 import (
 	_ "github.com/joint-online-judge/JOJ3/internal/executor/dummy"
diff --git a/internal/parser/all.go b/internal/parser/all.go
index c5ff8f9..29fbd96 100644
--- a/internal/parser/all.go
+++ b/internal/parser/all.go
@@ -1,4 +1,5 @@
-package parsers
+// Package parser contains all the parsers.
+package parser
 
 import (
 	_ "github.com/joint-online-judge/JOJ3/internal/parser/clangtidy"
diff --git a/internal/parser/clangtidy/convert.go b/internal/parser/clangtidy/convert.go
index 628e102..ccee81e 100644
--- a/internal/parser/clangtidy/convert.go
+++ b/internal/parser/clangtidy/convert.go
@@ -1,4 +1,3 @@
-// Referenced from https://github.com/yuriisk/clang-tidy-converter/blob/master/clang_tidy_converter/parser/clang_tidy_parser.py
 package clangtidy
 
 import (
@@ -9,6 +8,7 @@ import (
 	"strings"
 )
 
+// Referenced from https://github.com/yuriisk/clang-tidy-converter/blob/master/clang_tidy_converter/parser/clang_tidy_parser.py
 type Level int
 
 const (
diff --git a/internal/parser/plugin/meta.go b/internal/parser/plugin/meta.go
index 63c7939..b6255e6 100644
--- a/internal/parser/plugin/meta.go
+++ b/internal/parser/plugin/meta.go
@@ -2,7 +2,6 @@
 // dynamically. It is used for custom parsers.
 // The plugin needs to be located at `ModPath` and export a symbol with name
 // `SymName` that implements the stage.Parser interface.
-
 package plugin
 
 import "github.com/joint-online-judge/JOJ3/internal/stage"
diff --git a/internal/parser/tierscore/meta.go b/internal/parser/tierscore/meta.go
index 2b1528c..970b639 100644
--- a/internal/parser/tierscore/meta.go
+++ b/internal/parser/tierscore/meta.go
@@ -1,6 +1,5 @@
 // Package tierscore provides a parser for tiered scoring based on
 // time and memory constraints. Leave the field empty or 0 to disable.
-
 package tierscore
 
 import "github.com/joint-online-judge/JOJ3/internal/stage"
diff --git a/internal/stage/run.go b/internal/stage/run.go
index d4a910c..06a69d0 100644
--- a/internal/stage/run.go
+++ b/internal/stage/run.go
@@ -1,3 +1,6 @@
+// Package stage provides functionality to run stages. Each stage contains an
+// executor and multiple parsers. The executor executes the command and parsers
+// parse the output generated by the executor.
 package stage
 
 import (
diff --git a/pkg/healthcheck/all.go b/pkg/healthcheck/all.go
index 2293701..562e84a 100644
--- a/pkg/healthcheck/all.go
+++ b/pkg/healthcheck/all.go
@@ -1,3 +1,4 @@
+// Package healthcheck provides a set of health checks for a repository.
 package healthcheck
 
 import (
diff --git a/pkg/sample/sample.go b/pkg/sample/sample.go
index 6c9ab5a..20f40fa 100644
--- a/pkg/sample/sample.go
+++ b/pkg/sample/sample.go
@@ -1,3 +1,4 @@
+// Package sample provides a sample function that returns a Result.
 package sample
 
 import (