diff --git a/mie/dialect/builtin/builtin.c b/mie/dialect/builtin/builtin.c
index 5b8f870..f4a9d49 100644
--- a/mie/dialect/builtin/builtin.c
+++ b/mie/dialect/builtin/builtin.c
@@ -92,4 +92,6 @@ MIE_DIALECT_BEGIN(mie_builtin, struct builtin_dialect, "builtin")
 	MIE_DIALECT_ADD_ATTRIBUTE(mie_builtin_int);
 	MIE_DIALECT_ADD_ATTRIBUTE(mie_builtin_float);
 	MIE_DIALECT_ADD_TRAIT(mie_builtin_isolated_from_above);
+	MIE_DIALECT_ADD_TRAIT(mie_builtin_symbol_table);
+	MIE_DIALECT_ADD_INTERFACE(mie_builtin_symbol);
 MIE_DIALECT_END()
diff --git a/mie/dialect/builtin/interface/symbol.c b/mie/dialect/builtin/interface/symbol.c
new file mode 100644
index 0000000..e9a845b
--- /dev/null
+++ b/mie/dialect/builtin/interface/symbol.c
@@ -0,0 +1,7 @@
+#include <mie/dialect/builtin.h>
+#include <mie/interface/interface-definition.h>
+#include <mie/macros.h>
+
+MIE_INTERFACE_DEFINITION_BEGIN(mie_builtin_symbol, "symbol")
+	MIE_INTERFACE_DEFINITION_STRUCT(struct mie_symbol);
+MIE_INTERFACE_DEFINITION_END()
diff --git a/mie/dialect/builtin/trait/symbol-table.c b/mie/dialect/builtin/trait/symbol-table.c
new file mode 100644
index 0000000..675ebbb
--- /dev/null
+++ b/mie/dialect/builtin/trait/symbol-table.c
@@ -0,0 +1,21 @@
+#include <mie/dialect/builtin.h>
+#include <mie/dialect/dialect.h>
+#include <mie/macros.h>
+#include <mie/trait/trait-definition.h>
+#include <mie/trait/trait.h>
+
+static enum mie_status validate(
+	const struct mie_trait_definition *trait_def,
+	const struct mie_trait *trait, const struct mie_trait_target *target)
+{
+	return MIE_SUCCESS;
+}
+
+/* builtin.isolated-from-above trait:
+ * regions of an op that has this trait cannot capture or reference
+ * values defined in the enclosing scope. */
+MIE_TRAIT_DEFINITION_BEGIN(mie_builtin_symbol_table, "symbol-table")
+	MIE_TRAIT_DEFINITION_TARGETS(MIE_TRAIT_TARGET_OP | MIE_TRAIT_TARGET_TYPE);
+	MIE_TRAIT_DEFINITION_STRUCT(struct mie_symbol_table);
+	MIE_TRAIT_DEFINITION_VALIDATE(validate);
+MIE_TRAIT_DEFINITION_END()
diff --git a/mie/include/mie/dialect/builtin.h b/mie/include/mie/dialect/builtin.h
index 09a43f2..ea8c2be 100644
--- a/mie/include/mie/dialect/builtin.h
+++ b/mie/include/mie/dialect/builtin.h
@@ -3,11 +3,14 @@
 
 #include <blue/ds/string.h>
 #include <mie/attribute/attribute.h>
+#include <mie/interface/interface.h>
 #include <mie/misc.h>
+#include <mie/trait/trait.h>
 
 struct mie_dialect;
 
 struct mie_ctx;
+struct mie_op;
 struct mie_int_type;
 struct mie_float_type;
 
@@ -51,6 +54,15 @@ struct mie_index {
 	size_t i_value;
 };
 
+struct mie_symbol {
+	struct mie_interface sym_base;
+	const char *(*sym_get_name)(const struct mie_op *);
+};
+
+struct mie_symbol_table {
+	struct mie_trait tab_base;
+};
+
 struct mie_int_cache;
 struct mie_float_cache;
 struct mie_string_cache;