diff --git a/justfile b/justfile
index 0aaf144..b9db370 100644
--- a/justfile
+++ b/justfile
@@ -15,3 +15,7 @@ basic *args:
 # Run the test suite; extra arguments go to pytest
 test *args:
     uv run pytest {{args}}
+
+# Re-record the gameplay parity fixtures (only when gameplay should change)
+record-traces:
+    uv run python tests/game_trace.py
diff --git a/tests/game_trace.py b/tests/game_trace.py
index 131607d..a02b292 100644
--- a/tests/game_trace.py
+++ b/tests/game_trace.py
@@ -1,5 +1,6 @@
 import datetime
 import typing as T
+from pathlib import Path
 
 from pqcli import random
 from pqcli.config import StatType
@@ -67,3 +68,15 @@ def run_trace(seed: str, ticks: int = 3000) -> T.List[str]:
     for quest in player.quest_book.quests:
         lines.append(f"quest: {quest}")
     return lines
+
+
+SEEDS = ["alpha", "beta", "gamma"]
+FIXTURES = Path(__file__).parent / "fixtures"
+
+
+if __name__ == "__main__":
+    # Re-record the parity fixtures. Only do this on purpose, when a change
+    # is meant to alter gameplay.
+    for seed in SEEDS:
+        lines = run_trace(seed)
+        (FIXTURES / f"parity_{seed}.txt").write_text("\n".join(lines) + "\n")
diff --git a/tests/test_parity.py b/tests/test_parity.py
index 88010c1..08303c1 100644
--- a/tests/test_parity.py
+++ b/tests/test_parity.py
@@ -1,14 +1,10 @@
-from pathlib import Path
-
 import pytest
-from game_trace import run_trace
-
-FIXTURES = Path(__file__).parent / "fixtures"
+from game_trace import FIXTURES, SEEDS, run_trace
 
 
-@pytest.mark.parametrize("seed", ["alpha", "beta", "gamma"])
+@pytest.mark.parametrize("seed", SEEDS)
 def test_gameplay_matches_recorded_trace(seed: str) -> None:
-    # The fixtures were recorded before the word lists moved to data files;
-    # stock data must reproduce them exactly, RNG stream included.
+    # The fixtures pin down gameplay, RNG stream included. When a change is
+    # meant to alter gameplay, re-record them with `just record-traces`.
     expected = (FIXTURES / f"parity_{seed}.txt").read_text().splitlines()
     assert run_trace(seed) == expected