diff --git a/include/slibtool/slibtool_output.h b/include/slibtool/slibtool_output.h
new file mode 100644
index 0000000..cf94180
--- /dev/null
+++ b/include/slibtool/slibtool_output.h
@@ -0,0 +1,19 @@
+#ifndef SLIBTOOL_OUTPUT_H
+#define SLIBTOOL_OUTPUT_H
+
+#include <stdint.h>
+
+#define SLBT_PRETTY(x)			((uint64_t)x << 32)
+
+/* output actions */
+#define SLBT_OUTPUT_ARCHIVE_MEMBERS	0x00000001
+#define SLBT_OUTPUT_ARCHIVE_HEADERS	0x00000002
+#define SLBT_OUTPUT_ARCHIVE_SYMBOLS	0x00000004
+#define SLBT_OUTPUT_ARCHIVE_ARMAPS	0x00000008
+
+/* pretty-printer flags */
+#define SLBT_PRETTY_YAML		SLBT_PRETTY(0x00000001)
+#define SLBT_PRETTY_POSIX		SLBT_PRETTY(0x00000002)
+#define SLBT_PRETTY_HEXDATA		SLBT_PRETTY(0x00000004)
+
+#endif
diff --git a/project/headers.mk b/project/headers.mk
index 71b49aa..2e7a0af 100644
--- a/project/headers.mk
+++ b/project/headers.mk
@@ -2,6 +2,7 @@ API_HEADERS = \
 	$(PROJECT_DIR)/include/$(PACKAGE)/slibtool.h \
 	$(PROJECT_DIR)/include/$(PACKAGE)/slibtool_api.h \
 	$(PROJECT_DIR)/include/$(PACKAGE)/slibtool_arbits.h \
+	$(PROJECT_DIR)/include/$(PACKAGE)/slibtool_output.h \
 
 INTERNAL_HEADERS = \
 	$(PROJECT_DIR)/src/internal/argv/argv.h \