diff --git a/mie/diag/diag.c b/mie/diag/diag.c
index 4b195ae..c533167 100644
--- a/mie/diag/diag.c
+++ b/mie/diag/diag.c
@@ -76,7 +76,11 @@ void mie_diag_push_msg(
 		return;
 	}
 
-	if (msg >= dialect->d_nr_diag_msgs) {
+	if (msg >= dialect->d_nr_diag_msgs
+	    || !dialect->d_diag_msgs[msg].msg_content) {
+		fprintf(stderr, "FATAL: %lu is not a valid %s diag msg\n", msg,
+		        dialect_name);
+		abort();
 		return;
 	}
 
@@ -90,6 +94,20 @@ void mie_diag_push_msg(
 	b_queue_push_back(&diag->diag_components, &c_msg->msg_base.c_entry);
 }
 
+void mie_diag_push_string(struct mie_diag *diag, const char *str)
+{
+	struct mie_diag_c_msg *c_msg = malloc(sizeof *c_msg);
+	if (!c_msg) {
+		return;
+	}
+
+	memset(c_msg, 0x0, sizeof *c_msg);
+	c_msg->msg_base.c_type = MIE_DIAG_COMPONENT_MSG;
+	c_msg->msg_content = b_strdup(str);
+
+	b_queue_push_back(&diag->diag_components, &c_msg->msg_base.c_entry);
+}
+
 void mie_diag_push_snippet(
 	struct mie_diag *diag, unsigned long first_line, unsigned long last_line,
 	const struct mie_diag_amendment *amendments, size_t nr_amendments,
diff --git a/mie/include/mie/diag/diag.h b/mie/include/mie/diag/diag.h
index a59caa2..913ba76 100644
--- a/mie/include/mie/diag/diag.h
+++ b/mie/include/mie/diag/diag.h
@@ -4,6 +4,39 @@
 #include <blue/core/queue.h>
 #include <mie/parse/file-span.h>
 
+#define MIE_DIAG_HL(type, span)                                                \
+	{                                                                      \
+		.hl_type = MIE_DIAG_HIGHLIGHT_##type,                          \
+		.hl_span = (span),                                             \
+	}
+
+#define MIE_DIAG_ADD(str, loc)                                                 \
+	{                                                                      \
+		.a_type = MIE_DIAG_AMENDMENT_ADD, .__x = strlen(str),          \
+		.a_add = {                                                     \
+			.a_loc = (loc),                                        \
+				.a_str = (str), \
+		},                                                             \
+	}
+
+#define MIE_DIAG_REMOVE(len, llc)                                              \
+	{                                                                      \
+		.a_type = MIE_DIAG_AMENDMENT_REMOVE,                           \
+		.a_remove = {                                                  \
+			.a_loc = (loc),                                        \
+			.a_length = (len),                                     \
+		},                                                             \
+	}
+#define MIE_DIAG_REPLACE(len, str, loc)                                        \
+	{                                                                      \
+		.a_type = MIE_DIAG_AMENDMENT_REPLACE, .__x = strlen(str),      \
+		.a_replace = {                                                 \
+			.a_loc = (loc),                                        \
+			.a_length = (len),                                     \
+			.a_str = (str),                                        \
+		},                                                             \
+	}
+
 struct mie_ctx;
 struct mie_diag_class;
 struct mie_diag_amendment;
@@ -31,6 +64,7 @@ MIE_API void mie_diag_set_location(
 MIE_API void mie_diag_push_msg(
 	struct mie_diag *diag, struct mie_ctx *ctx, const char *dialect,
 	unsigned long msg, ...);
+MIE_API void mie_diag_push_string(struct mie_diag *diag, const char *str);
 MIE_API void mie_diag_push_snippet(
 	struct mie_diag *diag, unsigned long first_line, unsigned long last_line,
 	const struct mie_diag_amendment *amendmends, size_t nr_amendments,