diff --git a/cmd/ccache_exporter/main.go b/cmd/ccache_exporter/main.go
index 2ad92ab..3ba01cb 100644
--- a/cmd/ccache_exporter/main.go
+++ b/cmd/ccache_exporter/main.go
@@ -1,3 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package main
 
 import (
diff --git a/cmd/ccacheparser/main.go b/cmd/ccacheparser/main.go
index 06c8630..231f0eb 100644
--- a/cmd/ccacheparser/main.go
+++ b/cmd/ccacheparser/main.go
@@ -1,3 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package main
 
 import (
diff --git a/collector.go b/collector.go
index bf888f8..e44239a 100644
--- a/collector.go
+++ b/collector.go
@@ -1,8 +1,7 @@
-// Prometheus metrics collection.
-//
-// See:
-// - https://ccache.samba.org/
-// - https://prometheus.io/
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package ccache
 
 import (
@@ -30,6 +29,8 @@ type collector struct {
 	maxCacheSizeBytes        *prometheus.Desc
 }
 
+// NewCollector initializes and returns a Prometheus collector for ccache
+// metrics.
 func NewCollector() *collector {
 	return &collector{
 		call: prometheus.NewDesc(
@@ -101,6 +102,8 @@ func NewCollector() *collector {
 	}
 }
 
+// Describe publishes the description of each ccache metric to a metrics
+// channel.
 func (c *collector) Describe(ch chan<- *prometheus.Desc) {
 	ch <- c.call
 	ch <- c.callHit
@@ -115,6 +118,7 @@ func (c *collector) Describe(ch chan<- *prometheus.Desc) {
 	ch <- c.maxCacheSizeBytes
 }
 
+// Collect gathers metrics from ccache.
 func (c *collector) Collect(ch chan<- prometheus.Metric) {
 	out, err := exec.Command("ccache", "-s").Output()
 	if err != nil {
diff --git a/doc.go b/doc.go
new file mode 100644
index 0000000..b875176
--- /dev/null
+++ b/doc.go
@@ -0,0 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+// Package ccache provides a simple parser for ccache metrics, and a Prometheus
+// collector to expose these metrics for scraping.
+package ccache
diff --git a/parser.go b/parser.go
index f390b3e..7d675a1 100644
--- a/parser.go
+++ b/parser.go
@@ -1,3 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package ccache
 
 import (
diff --git a/parser_test.go b/parser_test.go
index b989640..626bc09 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -1,3 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package ccache
 
 import (
diff --git a/statistics.go b/statistics.go
index 4cea930..be28a71 100644
--- a/statistics.go
+++ b/statistics.go
@@ -1,3 +1,7 @@
+// Copyright 2018 VirtualTam.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 package ccache
 
 import (