diff --git a/docs/reference.md b/docs/reference.md
index 33ee391..f606086 100644
--- a/docs/reference.md
+++ b/docs/reference.md
@@ -195,10 +195,10 @@
    - "test_targets": A list of the labels for targets that are needed to run
      the tests we wish to run.
 
-   - "additional_compile_targets": A list of the labels for targets that we
-     wish to rebuild, but aren't necessarily needed for testing. The important
-     difference between this field and "test_targets" is that if an item in
-     the additional_compile_targets list refers to a group, then any
+   - "additional_compile_targets" (optional): A list of the labels for targets
+     that we wish to rebuild, but aren't necessarily needed for testing. The
+     important difference between this field and "test_targets" is that if an
+     item in the additional_compile_targets list refers to a group, then any
      dependencies of that group will be returned if they are out of date, but
      the group itself does not need to be. If the dependencies themselves are
      groups, the same filtering is repeated. This filtering can be used to
@@ -209,6 +209,8 @@
      This filtering behavior is also known as "pruning" the list of compile
      targets.
 
+     If "additional_compile_targets" is absent, it defaults to the empty list.
+
   If input_path is -, input is read from stdin.
 
   output_path is a path indicating where the results of the command are to be
diff --git a/src/gn/command_analyze.cc b/src/gn/command_analyze.cc
index 5c6c193..cf6985d 100644
--- a/src/gn/command_analyze.cc
+++ b/src/gn/command_analyze.cc
@@ -38,10 +38,10 @@
    - "test_targets": A list of the labels for targets that are needed to run
      the tests we wish to run.
 
-   - "additional_compile_targets": A list of the labels for targets that we
-     wish to rebuild, but aren't necessarily needed for testing. The important
-     difference between this field and "test_targets" is that if an item in
-     the additional_compile_targets list refers to a group, then any
+   - "additional_compile_targets" (optional): A list of the labels for targets
+     that we wish to rebuild, but aren't necessarily needed for testing. The
+     important difference between this field and "test_targets" is that if an
+     item in the additional_compile_targets list refers to a group, then any
      dependencies of that group will be returned if they are out of date, but
      the group itself does not need to be. If the dependencies themselves are
      groups, the same filtering is repeated. This filtering can be used to
@@ -52,6 +52,8 @@
      This filtering behavior is also known as "pruning" the list of compile
      targets.
 
+     If "additional_compile_targets" is absent, it defaults to the empty list.
+
   If input_path is -, input is read from stdin.
 
   output_path is a path indicating where the results of the command are to be