Isolate parsed provider parameters

integrations/ckprompt/request_flags.go

@@ -85,6 +85,7 @@ func (f ExecutionFlags[I]) bindings() []requestBinding[I] {
 }
 
 // NewExecutionFlags binds execution controls to a field of the caller's input.
+// Parsed provider parameters are copied when the binding is applied.
 func NewExecutionFlags[I any](destination func(*I) *ExecutionInput) ExecutionFlags[I] {
 	target := func(input *I) *promptkit.ExecutionTargetOverride {
 		value := destination(input)
@@ -104,7 +105,36 @@ func NewExecutionFlags[I any](destination func(*I) *ExecutionInput) ExecutionFla
 		ReasoningEffort:  executionFlag(requestFlags.ReasoningEffort.meta, parseDefinitionString, func(i *I, v string) { target(i).ReasoningEffort = &v }),
 		APIKeyEnv:        executionFlag(requestFlags.APIKeyEnv.meta, parseDefinitionString, func(i *I, v string) { target(i).APIKeyEnv = v }),
 		TransientRetries: executionFlag(requestFlags.TransientRetries.meta, strconv.Atoi, func(i *I, v int) { destination(i).TransientRetries = &v }),
-		ExtraParams:      executionFlag(requestFlags.ExtraParams.meta, parseExtraParams, func(i *I, v map[string]any) { target(i).ExtraParams = v }),
+		ExtraParams:      executionFlag(requestFlags.ExtraParams.meta, parseExtraParams, func(i *I, v map[string]any) { target(i).ExtraParams = copyProviderParams(v) }),
+	}
+}
+
+func copyProviderParams(params map[string]any) map[string]any {
+	if params == nil {
+		return nil
+	}
+	result := make(map[string]any, len(params))
+	for key, value := range params {
+		result[key] = copyProviderValue(value)
+	}
+	return result
+}
+
+func copyProviderValue(value any) any {
+	switch value := value.(type) {
+	case map[string]any:
+		return copyProviderParams(value)
+	case []any:
+		if value == nil {
+			return []any(nil)
+		}
+		result := make([]any, len(value))
+		for i, element := range value {
+			result[i] = copyProviderValue(element)
+		}
+		return result
+	default:
+		return value
 	}
 }