diff --git a/doc/shackle.md b/doc/shackle.md
index 6282f85..fb1145e 100644
--- a/doc/shackle.md
+++ b/doc/shackle.md
@@ -26,7 +26,7 @@ backlog_size() = pos_integer()
 
 
 <pre><code>
-cast() = #cast{client = undefined | <a href="#type-client">client()</a>, pid = undefined | pid(), pool_name = undefined | <a href="#type-pool_name">pool_name()</a>, ref = undefined | reference(), reply = undefined | term(), request = undefined | term(), timestamp = undefined | <a href="erlang.md#type-timestamp">erlang:timestamp()</a>, timing = [pos_integer()]}
+cast() = #cast{client = undefined | <a href="#type-client">client()</a>, pid = undefined | pid(), reply = undefined | term(), request = undefined | term(), request_id = undefined | <a href="#type-request_id">request_id()</a>, timestamp = undefined | <a href="erlang.md#type-timestamp">erlang:timestamp()</a>, timing = [pos_integer()]}
 </code></pre>
 
 
diff --git a/doc/shackle_queue.md b/doc/shackle_queue.md
index ae1a143..7fc136c 100644
--- a/doc/shackle_queue.md
+++ b/doc/shackle_queue.md
@@ -26,7 +26,7 @@ backlog_size() = pos_integer()
 
 
 <pre><code>
-cast() = #cast{client = undefined | <a href="#type-client">client()</a>, pid = undefined | pid(), pool_name = undefined | <a href="#type-pool_name">pool_name()</a>, ref = undefined | reference(), reply = undefined | term(), request = undefined | term(), timestamp = undefined | <a href="erlang.md#type-timestamp">erlang:timestamp()</a>, timing = [pos_integer()]}
+cast() = #cast{client = undefined | <a href="#type-client">client()</a>, pid = undefined | pid(), reply = undefined | term(), request = undefined | term(), request_id = undefined | <a href="#type-request_id">request_id()</a>, timestamp = undefined | <a href="erlang.md#type-timestamp">erlang:timestamp()</a>, timing = [pos_integer()]}
 </code></pre>
 
 
@@ -122,6 +122,16 @@ pool_strategy() = random | round_robin
 
 
 
+### <a name="type-request_id">request_id()</a> ###
+
+
+<pre><code>
+request_id() = {<a href="#type-pool_name">pool_name()</a>, reference()}
+</code></pre>
+
+
+
+
 ### <a name="type-server_name">server_name()</a> ###