diff --git a/userspace/engine/falco_engine.cpp b/userspace/engine/falco_engine.cpp
index a59bb201..98d2ca04 100644
--- a/userspace/engine/falco_engine.cpp
+++ b/userspace/engine/falco_engine.cpp
@@ -819,6 +819,19 @@ void falco_engine::get_json_used_plugins(
 	const std::unordered_set<std::string>& fields,
 	const std::vector<std::shared_ptr<sinsp_plugin>>& plugins) const
 {
+	// note: condition and output fields may have an argument, so
+	// we need to isolate the field names
+	std::unordered_set<std::string> fieldnames;
+	for (auto f: fields)
+	{
+		auto argpos = f.find('[');
+		if (argpos != std::string::npos)
+		{
+			f = f.substr(0, argpos);
+		}
+		fieldnames.insert(f);
+	}
+
 	out = Json::arrayValue;	
 	for (const auto& p : plugins)
 	{
@@ -846,7 +859,7 @@ void falco_engine::get_json_used_plugins(
 			{
 				for (const auto &f : p->fields())
 				{
-					if (!used && fields.find(f.m_name) != fields.end())
+					if (!used && fieldnames.find(f.m_name) != fieldnames.end())
 					{
 						out.append(p->name());
 						used = true;
diff --git a/userspace/engine/filter_details_resolver.cpp b/userspace/engine/filter_details_resolver.cpp
index 7ab1d8e3..81a9a407 100644
--- a/userspace/engine/filter_details_resolver.cpp
+++ b/userspace/engine/filter_details_resolver.cpp
@@ -19,6 +19,16 @@ limitations under the License.
 
 using namespace libsinsp::filter;
 
+std::string get_field_name(const std::string& name, const std::string& arg)
+{
+	std::string fld = name;
+	if (!arg.empty())
+	{
+		fld += "[" + arg + "]";
+	}
+	return fld;
+}
+
 void filter_details::reset()
 {
 	fields.clear();
@@ -86,7 +96,7 @@ void filter_details_resolver::visitor::visit(ast::list_expr* e)
 void filter_details_resolver::visitor::visit(ast::binary_check_expr* e)
 {
 	m_expect_macro = false;
-	m_details.fields.insert(e->field);
+	m_details.fields.insert(get_field_name(e->field, e->arg));
 	m_details.operators.insert(e->op);
 	if (e->field == "evt.type" || e->field == "evt.asynctype")
 	{
@@ -105,7 +115,7 @@ void filter_details_resolver::visitor::visit(ast::binary_check_expr* e)
 void filter_details_resolver::visitor::visit(ast::unary_check_expr* e)
 {
 	m_expect_macro = false;
-	m_details.fields.insert(e->field);
+	m_details.fields.insert(get_field_name(e->field, e->arg));
 	m_details.operators.insert(e->op);
 }