diff --git a/docs/configuration.md b/docs/configuration.md
index 520f2765..2f468d7a 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -436,6 +436,10 @@ token_url: <string>
 # Optional parameters to append to the token URL.
 endpoint_params:
   [ <string>: <string> ... ]
+
+# Configures the token request's TLS settings.
+tls_config:
+  [ <tls_config> ]
 ```
 
 ## `<tls_config>`