diff --git a/discovery/discovery.go b/discovery/discovery.go
index 0ad3d0c18..4207606fd 100644
--- a/discovery/discovery.go
+++ b/discovery/discovery.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package discovery provides an implementation of the cluster discovery that
+// is used by etcd.
 package discovery
 
 import (
diff --git a/error/error.go b/error/error.go
index 56facdc01..499823dbb 100644
--- a/error/error.go
+++ b/error/error.go
@@ -12,9 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// error package describes errors in etcd project.
-// When any change happens, Documentation/errorcode.md needs to be updated
-// correspondingly.
+// error package describes errors in etcd project. When any change happens,
+// Documentation/errorcode.md needs to be updated correspondingly.
 package error
 
 import (
diff --git a/discovery/doc.go b/etcdctl/command/doc.go
similarity index 83%
rename from discovery/doc.go
rename to etcdctl/command/doc.go
index 18cfd78c1..7e95e656a 100644
--- a/discovery/doc.go
+++ b/etcdctl/command/doc.go
@@ -12,9 +12,5 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/*
-Package discovery provides an implementation of the cluster discovery that
-is used by etcd.
-
-*/
-package discovery
+// Package command is a set of libraries for etcdctl commands.
+package command
diff --git a/etcdctl/main.go b/etcdctl/main.go
index c2fd73346..57567d319 100644
--- a/etcdctl/main.go
+++ b/etcdctl/main.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// etcdctl is a command line application that controls etcd.
 package main
 
 import (
diff --git a/etcdserver/etcdhttp/httptypes/doc.go b/etcdctlv3/command/doc.go
similarity index 82%
rename from etcdserver/etcdhttp/httptypes/doc.go
rename to etcdctlv3/command/doc.go
index fa0158020..b9420fe90 100644
--- a/etcdserver/etcdhttp/httptypes/doc.go
+++ b/etcdctlv3/command/doc.go
@@ -12,8 +12,5 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/*
-Package httptypes defines how etcd's HTTP API entities are serialized to and deserialized from JSON.
-*/
-
-package httptypes
+// Package command is a set of libraries for etcd v3 commands.
+package command
diff --git a/etcdctlv3/main.go b/etcdctlv3/main.go
index 835368b33..75e9c9d6d 100644
--- a/etcdctlv3/main.go
+++ b/etcdctlv3/main.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// etcdctlv3 is a command line application that utilizes v3 API.
 package main
 
 import (
diff --git a/etcdserver/api/v3rpc/key.go b/etcdserver/api/v3rpc/key.go
index cf4bd4129..449182ccc 100644
--- a/etcdserver/api/v3rpc/key.go
+++ b/etcdserver/api/v3rpc/key.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package v3rpc implements etcd v3 RPC system based on gRPC.
 package v3rpc
 
 import (
diff --git a/etcdserver/auth/auth.go b/etcdserver/auth/auth.go
index 609ee7aeb..46c1de24e 100644
--- a/etcdserver/auth/auth.go
+++ b/etcdserver/auth/auth.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package auth implements etcd authentication.
 package auth
 
 import (
diff --git a/etcdserver/doc.go b/etcdserver/doc.go
new file mode 100644
index 000000000..a444d528d
--- /dev/null
+++ b/etcdserver/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package etcdserver defines how etcd servers interact and store their states.
+package etcdserver
diff --git a/etcdserver/etcdhttp/doc.go b/etcdserver/etcdhttp/doc.go
new file mode 100644
index 000000000..84883aaf1
--- /dev/null
+++ b/etcdserver/etcdhttp/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package etcdhttp provides etcd client and server implementations.
+package etcdhttp
diff --git a/etcdserver/etcdhttp/httptypes/member.go b/etcdserver/etcdhttp/httptypes/member.go
index 30ecbb539..432f73a4f 100644
--- a/etcdserver/etcdhttp/httptypes/member.go
+++ b/etcdserver/etcdhttp/httptypes/member.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package httptypes defines how etcd's HTTP API entities are serialized to and
+// deserialized from JSON.
 package httptypes
 
 import (
diff --git a/etcdserver/stats/stats.go b/etcdserver/stats/stats.go
index 5bda72327..a917a120b 100644
--- a/etcdserver/stats/stats.go
+++ b/etcdserver/stats/stats.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package stats defines a standard interface for etcd cluster statistics.
 package stats
 
 import "github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
diff --git a/pkg/cors/cors.go b/pkg/cors/cors.go
index b1a0baf08..d149d10a2 100644
--- a/pkg/cors/cors.go
+++ b/pkg/cors/cors.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package cors handles cross-origin HTTP requests (CORS).
 package cors
 
 import (
diff --git a/pkg/crc/crc.go b/pkg/crc/crc.go
index b4e7c8da0..4b998a484 100644
--- a/pkg/crc/crc.go
+++ b/pkg/crc/crc.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Package crc provides utility function for cyclic redundancy check
+// algorithms.
 package crc
 
 import (
diff --git a/pkg/fileutil/fileutil.go b/pkg/fileutil/fileutil.go
index 7a39ca554..b728a4953 100644
--- a/pkg/fileutil/fileutil.go
+++ b/pkg/fileutil/fileutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package fileutil implements utility functions related to files and paths.
 package fileutil
 
 import (
diff --git a/pkg/flags/flag.go b/pkg/flags/flag.go
index 30a1b11e1..9dc5a085b 100644
--- a/pkg/flags/flag.go
+++ b/pkg/flags/flag.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package flags implements command-line flag parsing.
 package flags
 
 import (
diff --git a/pkg/httputil/cancelreq.go b/pkg/httputil/cancelreq.go
index ebebcb3d9..e3a7a7422 100644
--- a/pkg/httputil/cancelreq.go
+++ b/pkg/httputil/cancelreq.go
@@ -6,6 +6,7 @@
 
 // +build go1.5
 
+// Package httputil provides HTTP utility functions.
 package httputil
 
 import "net/http"
diff --git a/pkg/idutil/id.go b/pkg/idutil/id.go
index 02f3aa866..0ba570cff 100644
--- a/pkg/idutil/id.go
+++ b/pkg/idutil/id.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package idutil implements utility functions for generating unique,
+// randomized ids.
 package idutil
 
 import (
diff --git a/pkg/ioutil/reader.go b/pkg/ioutil/reader.go
index 412f3915a..8ef9a9330 100644
--- a/pkg/ioutil/reader.go
+++ b/pkg/ioutil/reader.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package ioutil implements I/O utility functions.
 package ioutil
 
 import "io"
diff --git a/pkg/netutil/netutil.go b/pkg/netutil/netutil.go
index 62aacf2c3..771b863f2 100644
--- a/pkg/netutil/netutil.go
+++ b/pkg/netutil/netutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package netutil implements network-related utility functions.
 package netutil
 
 import (
diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index 6e8f9f035..6ece3b18d 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package osutil implements operating system-related utility functions.
 package osutil
 
 import (
diff --git a/pkg/pathutil/path.go b/pkg/pathutil/path.go
index 82fd1db39..f26254ba9 100644
--- a/pkg/pathutil/path.go
+++ b/pkg/pathutil/path.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Package pathutil implements utility functions for handling slash-separated
+// paths.
 package pathutil
 
 import "path"
diff --git a/pkg/pbutil/pbutil.go b/pkg/pbutil/pbutil.go
index 66693a2f2..d22d945b0 100644
--- a/pkg/pbutil/pbutil.go
+++ b/pkg/pbutil/pbutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package pbutil defines interfaces for handling Protocol Buffer objects.
 package pbutil
 
 import "github.com/coreos/etcd/Godeps/_workspace/src/github.com/coreos/pkg/capnslog"
diff --git a/pkg/runtime/fds_linux.go b/pkg/runtime/fds_linux.go
index 85297c09d..d81114405 100644
--- a/pkg/runtime/fds_linux.go
+++ b/pkg/runtime/fds_linux.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package runtime implements utility functions for runtime systems.
 package runtime
 
 import (
diff --git a/pkg/testutil/testutil.go b/pkg/testutil/testutil.go
index 49a25da00..a884bd10d 100644
--- a/pkg/testutil/testutil.go
+++ b/pkg/testutil/testutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package testutil provides test utility functions.
 package testutil
 
 import (
diff --git a/pkg/timeutil/timeutil.go b/pkg/timeutil/timeutil.go
index 58da59397..272e6f529 100644
--- a/pkg/timeutil/timeutil.go
+++ b/pkg/timeutil/timeutil.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package timeutil providese time-related utility functions.
 package timeutil
 
 import "time"
diff --git a/pkg/transport/doc.go b/pkg/transport/doc.go
new file mode 100644
index 000000000..4411e4487
--- /dev/null
+++ b/pkg/transport/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package transport implements various HTTP transport utilities based on Go
+// net package.
+package transport
diff --git a/pkg/types/doc.go b/pkg/types/doc.go
new file mode 100644
index 000000000..04b4c38d1
--- /dev/null
+++ b/pkg/types/doc.go
@@ -0,0 +1,17 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package types declares various data types and implements type-checking
+// functions.
+package types
diff --git a/pkg/wait/wait.go b/pkg/wait/wait.go
index e8cf073f8..141f24981 100644
--- a/pkg/wait/wait.go
+++ b/pkg/wait/wait.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package wait provides utility functions for polling, listening using Go
+// channel.
 package wait
 
 import (
diff --git a/pkg/wait/wait_time.go b/pkg/wait/wait_time.go
index 99fb3a96c..1ed277084 100644
--- a/pkg/wait/wait_time.go
+++ b/pkg/wait/wait_time.go
@@ -12,22 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/*
-   Copyright 2015 CoreOS, Inc.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
-
 package wait
 
 import (
diff --git a/pkg/wait/wait_time_test.go b/pkg/wait/wait_time_test.go
index 5f7ad6949..c194600af 100644
--- a/pkg/wait/wait_time_test.go
+++ b/pkg/wait/wait_time_test.go
@@ -12,22 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/*
-
-   Copyright 2015 CoreOS, Inc.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-*/
 package wait
 
 import (
diff --git a/proxy/doc.go b/proxy/doc.go
new file mode 100644
index 000000000..181a3e0fa
--- /dev/null
+++ b/proxy/doc.go
@@ -0,0 +1,18 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package proxy implements etcd proxy node. The etcd proxy acts as a reverse
+// proxy forwarding client requests to active etcd cluster members, and does
+// not participate in consensus.
+package proxy
diff --git a/raft/rafttest/doc.go b/raft/rafttest/doc.go
new file mode 100644
index 000000000..85ef5e7ff
--- /dev/null
+++ b/raft/rafttest/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package rafttest provides functional tests for etcd's raft implementation.
+package rafttest
diff --git a/rafthttp/doc.go b/rafthttp/doc.go
new file mode 100644
index 000000000..320f842b8
--- /dev/null
+++ b/rafthttp/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package rafthttp implements HTTP transportation layer for etcd/raft pkg.
+package rafthttp
diff --git a/snap/snapshotter.go b/snap/snapshotter.go
index dd4fe02af..c80849c97 100644
--- a/snap/snapshotter.go
+++ b/snap/snapshotter.go
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package snap stores raft nodes' states with snapshots.
 package snap
 
 import (
diff --git a/storage/backend/doc.go b/storage/backend/doc.go
new file mode 100644
index 000000000..50cd8d5cf
--- /dev/null
+++ b/storage/backend/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package backend defines a standard interface for etcd's backend storage.
+package backend
diff --git a/storage/doc.go b/storage/doc.go
new file mode 100644
index 000000000..7de6851c5
--- /dev/null
+++ b/storage/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package storage defines etcd's stable storage.
+package storage
diff --git a/store/doc.go b/store/doc.go
new file mode 100644
index 000000000..08cb924ab
--- /dev/null
+++ b/store/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package store defines etcd's in-memory key/value store.
+package store
diff --git a/version/version.go b/version/version.go
index 464911f0c..976917e95 100644
--- a/version/version.go
+++ b/version/version.go
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package version implements etcd version parsing and contains latest version
+// information.
 package version
 
 import (