diff --git a/README b/README
index 5b4caba..b6cbf16 100644
--- a/README
+++ b/README
@@ -29,4 +29,4 @@ The following outputs are supported:
 
 	move_dir <x> <y>
 		<x> and <y> are integer offsets relative
-		to the current position
+		to the current position; may be just {-1,0,1}
diff --git a/connection.cc b/connection.cc
index 9425e6b..9832ec3 100644
--- a/connection.cc
+++ b/connection.cc
@@ -43,6 +43,8 @@ connection::actions(class agent *agent)
 		if (!cmd.compare("move_dir")) {
 			int x = 0, y = 0;
 			sscanf(line.c_str(), "%d %d", &x, &y);
+			if (x < -1) x = -1; if (x > 1) x = 1;
+			if (y < -1) y = -1; if (y > 1) y = 1;
 			agent->move_dir(x, y);
 		} else {
 			std::cout << "unknown line " << cmd << " " << line << " ...\n";