diff --git a/internal/proto/asynq.proto b/internal/proto/asynq.proto
index 199c9a1..788f43d 100644
--- a/internal/proto/asynq.proto
+++ b/internal/proto/asynq.proto
@@ -1,3 +1,7 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
 syntax = "proto3";
 package asynq;
 
@@ -5,57 +9,110 @@ import "google/protobuf/timestamp.proto";
 
 option go_package = "github.com/hibiken/asynq/internal/proto";
 
-// TaskMessage is the internal representation of a task with additional metadata fields.
-// See base.TaskMessage for details of each field.
+// TaskMessage is the internal representation of a task with additional
+// metadata fields.
 message TaskMessage {
+	// Type indicates the kind of the task to be performed.
   string type = 1;
 
+	// Payload holds data needed to process the task.
   bytes payload = 2;
 
+	// Unique identifier for the task.
   string id = 3;
 
+	// Name of the queue to which this task belongs.
   string queue = 4;
 
+	// Max number of retries for this task.
   int32 retry = 5;
 
+	// Number of times this task has been retried so far.
   int32 retried = 6;
 
+	// Error message from the last failure.
   string error_msg = 7;
 
+	// Timeout specifies timeout in seconds.
+	// Use zero to indicate no timeout.
   int64 timeout = 8;
 
+	// Deadline specifies the deadline for the task in Unix time,
+	// the number of seconds elapsed since January 1, 1970 UTC.
+	// Use zero to indicate no deadline.
   int64 deadline = 9;
 
+	// UniqueKey holds the redis key used for uniqueness lock for this task.
+	// Empty string indicates that no uniqueness lock was used.
   string unique_key = 10;
 };
 
 // ServerInfo holds information about a running server.
 message ServerInfo {
+  // Host machine the server is running on.
   string host = 1;
+
+  // PID of the server process.
   int32 pid = 2;
+
+  // Unique identifier for this server.
   string server_id = 3;
+
+  // Maximum number of concurrency this server will use.
   int32 concurrency = 4;
+
+  // List of queue names with their priorities.
+  // The server will consume tasks from the queues and prioritize
+  // queues with higher priority numbers.
   map<string, int32> queues = 5;
+
+  // If set, the server will always consume tasks from a queue with higher
+  // priority.
   bool strict_priority = 6;
+
+  // Status indicates the status of the server.
   string status = 7;
+
+  // Time this server was started.
   google.protobuf.Timestamp start_time = 8;
+
+  // Number of workers currently processing tasks.
   int32 active_worker_count = 9;
 };
 
 // WorkerInfo holds information about a running worker.
 message WorkerInfo {
+  // Host matchine this worker is running on.
   string host = 1;
+
+  // PID of the process in which this worker is running.
   int32 pid = 2;
+
+  // ID of the server in which this worker is running.
   string server_id = 3;
+
+  // ID of the task this worker is processing.
   string task_id = 4;
+
+  // Type of the task this worker is processing.
   string task_type = 5;
+
+  // Payload of the task this worker is processing.
   bytes task_payload = 6;
+
+  // Name of the queue the task the worker is processing belongs.
   string queue = 7;
+
+  // Time this worker started processing the task.
   google.protobuf.Timestamp start_time = 8;
+
+  // Deadline by which the worker needs to complete processing 
+  // the task. If worker exceeds the deadline, the task will fail.
   google.protobuf.Timestamp deadline = 9;
 };
 
-// SchedulerEntry holds information about a periodic task registered with a scheduler.
+// SchedulerEntry holds information about a periodic task registered 
+// with a scheduler.
 message SchedulerEntry {
 	// Identifier of the scheduler entry.
 	string id = 1;
@@ -80,7 +137,8 @@ message SchedulerEntry {
   google.protobuf.Timestamp prev_enqueue_time = 7;
 };
 
-// SchedulerEnqueueEvent holds information about an enqueue event by a scheduler.
+// SchedulerEnqueueEvent holds information about an enqueue event
+// by a scheduler.
 message SchedulerEnqueueEvent {
 	// ID of the task that was enqueued.
   string task_id = 1;