diff --git a/src/models.py b/src/models.py
index df196923..a5b9d00a 100644
--- a/src/models.py
+++ b/src/models.py
@@ -35,6 +35,17 @@ import sys
 
 from typing import Any, Dict, List
 
+from src.mma import TrackMetadata
+
+# Legacy alias: the original models.py had a TrackMetadata dataclass named
+# 'Metadata' (before Phase 3a moved it to src.mma.py). Existing tests +
+# consumers use 'from src.models import Metadata' expecting the dataclass.
+# We re-export the dataclass here so the legacy import path resolves to
+# the same object. The Metadata TYPE ALIAS (from src.type_aliases) is the
+# boundary wire type; legacy consumers wanting the dataclass should
+# migrate to 'from src.mma import TrackMetadata'.
+Metadata = TrackMetadata  # noqa: F401 — legacy class name re-export
+
 
 DEFAULT_TOOL_CATEGORIES: Dict[str, List[str]] = {
  "General": ["read_file", "list_directory", "search_files", "get_tree", "get_file_summary"],