Add ConfigUnknown field
diff --git a/plan.go b/plan.go
index 93d7165..579e8d7 100644
--- a/plan.go
+++ b/plan.go
@@ -310,6 +310,7 @@
 	// ConfigValues is the JSON representation of the values in the config block of the action
 	ConfigValues    interface{} `json:"config_values,omitempty"`
 	ConfigSensitive interface{} `json:"config_sensitive,omitempty"`
+	ConfigUnknown   interface{} `json:"config_unknown,omitempty"`
 
 	// ProviderName allows the property "type" to be interpreted unambiguously
 	// in the unusual situation where a provider offers a type whose
diff --git a/plan_test.go b/plan_test.go
index 1c76a12..9da2ef6 100644
--- a/plan_test.go
+++ b/plan_test.go
@@ -167,6 +167,7 @@
 				"ratio": nil,
 			},
 			ConfigSensitive:        map[string]interface{}{},
+			ConfigUnknown:          map[string]interface{}{},
 			ProviderName:           "registry.terraform.io/austinvalle/bufo",
 			LifecycleActionTrigger: nil,
 			InvokeActionTrigger:    &InvokeActionTrigger{},
diff --git a/testdata/actions/plan.json b/testdata/actions/plan.json
index eb20f1b..a3a2e36 100644
--- a/testdata/actions/plan.json
+++ b/testdata/actions/plan.json
@@ -1 +1 @@
-{"format_version":"1.2","planned_values":{"root_module":{}},"complete":true,"configuration":{"provider_config":{"bufo":{"name":"bufo","full_name":"registry.terraform.io/austinvalle/bufo"}},"root_module":{}},"timestamp":"2025-09-12T09:56:02Z","action_invocations":[{"address":"action.bufo_print.success","type":"bufo_print","name":"success","config_values":{"color":null,"name":"bufo-the-builder","ratio":null},"config_sensitive":{},"provider_name":"registry.terraform.io/austinvalle/bufo","invoke_action_trigger":{}}]}
+{"format_version":"1.2","planned_values":{"root_module":{}},"complete":true,"configuration":{"provider_config":{"bufo":{"name":"bufo","full_name":"registry.terraform.io/austinvalle/bufo"}},"root_module":{}},"timestamp":"2025-09-12T09:56:02Z","action_invocations":[{"address":"action.bufo_print.success","type":"bufo_print","name":"success","config_values":{"color":null,"name":"bufo-the-builder","ratio":null},"config_sensitive":{},"config_unknown":{},"provider_name":"registry.terraform.io/austinvalle/bufo","invoke_action_trigger":{}}]}