diff --git a/lib/protocol.js b/lib/protocol.js
index 287fbb5..70733ac 100644
--- a/lib/protocol.js
+++ b/lib/protocol.js
@@ -727,9 +727,17 @@ function readEntityMetadata(buffer, offset) {
     type = item >> 5;
     typeName = entityMetadataTypes[type];
     dataType = types[typeName];
-    assert.ok(dataType, "unrecognized entity metadata type " + type);
+    if (!dataType) {
+      return {
+        error: "unrecognized entity metadata type " + type
+      }
+    }
     reader = dataType[0];
-    assert.ok(reader, "missing reader for entity metadata type " + type);
+    if (!reader) {
+      return {
+        error: "missing reader for entity metadata type " + type
+      }
+    }
     results = reader(buffer, cursor);
     if (! results) return null;
     metadata.push({
@@ -808,7 +816,11 @@ function readMapChunkBulk (buffer, offset) {
     });
   }
 
-  assert.strictEqual(chunkColumnCount, meta.length);
+  if (chunkColumnCount !== meta.length) {
+    return {
+      error: "ChunkColumnCount different from length of meta"
+    }
+  }
 
   return {
     value: {