diff --git a/docs/configuration/configuration.md b/docs/configuration/configuration.md
index 3a9ace2b6c..db41c3247d 100644
--- a/docs/configuration/configuration.md
+++ b/docs/configuration/configuration.md
@@ -427,11 +427,16 @@ Where `<job_name>` must be unique across all scrape configurations.
 A `tls_config` allows configuring TLS connections.
 
 ```yaml
-# CA certificate to validate API server certificate with.
+# CA certificate to validate API server certificate with. At most one of ca and ca_file is allowed.
+[ ca: <string> ]
 [ ca_file: <filename> ]
 
-# Certificate and key files for client cert authentication to the server.
+# Certificate and key for client cert authentication to the server.
+# At most one of cert and cert_file is allowed.
+# At most one of key and key_file is allowed.
+[ cert: <string> ]
 [ cert_file: <filename> ]
+[ key: <secret> ]
 [ key_file: <filename> ]
 
 # ServerName extension to indicate the name of the server.