diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..472a172
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,11 @@
+# Python bytecode cache
+__pycache__/
+*.py[cod]
+
+# Machine state from bot runs -- reproducible, not source
+deck.json
+
+# Run artifacts written by run.py / JEV_TRACE during live sessions
+capture/live_*.json
+capture/decisions.jsonl
+capture/jev*.jsonl