diff --git a/Makefile b/Makefile
index b806791..2efc5d9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: test conformance lint typecheck check all
+.PHONY: test conformance lint typecheck check all sync-schema
 
 # Unit tests — the implementation's own suite. Hermetic and offline.
 test:
@@ -11,6 +11,11 @@ test:
 conformance:
 	pytest conformance -q
 
+# Refresh the bundled JSON Schema from fruwehq/harel at the matching version tag
+# (or HAREL_SPEC_DIR=/path/to/harel). The schema-drift test guards that they match.
+sync-schema:
+	python scripts/sync_schema.py
+
 lint:
 	ruff check .
 
diff --git a/scripts/sync_schema.py b/scripts/sync_schema.py
new file mode 100644
index 0000000..5cb6fb3
--- /dev/null
+++ b/scripts/sync_schema.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+"""Refresh the bundled JSON Schema from the spec repo (fruwehq/harel).
+
+Writes ``src/harel/data/machine.schema.json`` from harel's
+``schema/machine.schema.json`` at the tag matching this package's version (falling back
+to ``main``), or from a local checkout via ``HAREL_SPEC_DIR``. This removes the manual
+copy step; the schema-drift test still guards that the two stay in sync.
+
+Usage: ``python scripts/sync_schema.py``  (or ``make sync-schema``).
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import re
+import sys
+import urllib.error
+import urllib.request
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+DEST = ROOT / "src" / "harel" / "data" / "machine.schema.json"
+ABOUT = ROOT / "src" / "harel" / "__about__.py"
+
+
+def _version() -> str:
+    m = re.search(r'__version__\s*=\s*"([^"]+)"', ABOUT.read_text(encoding="utf-8"))
+    if m is None:
+        raise SystemExit(f"could not read version from {ABOUT}")
+    return m.group(1)
+
+
+def _fetch() -> str:
+    override = os.environ.get("HAREL_SPEC_DIR")
+    if override:
+        return (Path(override) / "schema" / "machine.schema.json").read_text(encoding="utf-8")
+    last: Exception | None = None
+    for ref in (f"v{_version()}", "main"):
+        url = f"https://raw.githubusercontent.com/fruwehq/harel/{ref}/schema/machine.schema.json"
+        try:
+            with urllib.request.urlopen(url, timeout=10) as resp:  # noqa: S310 (fixed host)
+                return resp.read().decode("utf-8")
+        except urllib.error.URLError as exc:
+            last = exc
+    raise SystemExit(f"could not fetch schema from fruwehq/harel: {last}")
+
+
+def main() -> int:
+    text = _fetch()
+    json.loads(text)  # sanity check: valid JSON before overwriting
+    if DEST.read_text(encoding="utf-8") == text:
+        print(f"{DEST.relative_to(ROOT)} already up to date")
+        return 0
+    DEST.write_text(text, encoding="utf-8")
+    print(f"updated {DEST.relative_to(ROOT)}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())