diff --git a/README.md b/README.md
index 25463e7..efc4e67 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ and emit; their records flow into the handlers `log_setup` wired.
 ## Install
 
 ```
-log_setup @ git+ssh://git@git.rethinkstudios.io/rethink-public/log_setup.git@v0.3.0
+log_setup @ git+ssh://git@git.rethinkstudios.io/rethink-public/log_setup.git@v0.3.1
 ```
 
 No dependencies — stdlib only.
diff --git a/pyproject.toml b/pyproject.toml
index 411437d..498a259 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "log_setup"
-version = "0.3.0"
+version = "0.3.1"
 description = "stdlib app-entry-point logging setup: live run.log, rotation, gzip, retention, consistent format"
 requires-python = ">=3.10"
 dependencies = []
diff --git a/src/log_setup/__init__.py b/src/log_setup/__init__.py
index c8eb6d6..8633ee5 100644
--- a/src/log_setup/__init__.py
+++ b/src/log_setup/__init__.py
@@ -19,4 +19,4 @@ from .setup import setup_logging
 
 __all__ = ["setup_logging"]
 
-__version__ = "0.3.0"
+__version__ = "0.3.1"
diff --git a/src/log_setup/formats.py b/src/log_setup/formats.py
index ddd8769..a0e079b 100644
--- a/src/log_setup/formats.py
+++ b/src/log_setup/formats.py
@@ -15,6 +15,11 @@ DEFAULT_FORMAT = "%(asctime)s | %(name)s | %(levelname)s | %(message)s"
 DEFAULT_DATEFMT = "%Y-%m-%d %H:%M:%S"
 
 _RESERVED = frozenset(vars(logging.makeLogRecord({})).keys()) | {"message", "asctime"}
+# this formatter's own canonical output keys — stdlib's LogRecord rejects `extra` keys
+# colliding with real attribute names (e.g. `module`), but `time`/`level` are NOT
+# LogRecord attrs, so a caller's extra={"time":...}/{"level":...} would otherwise
+# overwrite the UTC timestamp / levelname. guard them explicitly
+_OUTPUT_KEYS = frozenset({"time", "level", "module", "message"})
 
 
 class JsonLinesFormatter(logging.Formatter):
@@ -38,7 +43,7 @@ class JsonLinesFormatter(logging.Formatter):
             "message": record.getMessage(),
         }
         for key, value in record.__dict__.items():
-            if key not in _RESERVED and not key.startswith("_"):
+            if key not in _RESERVED and key not in _OUTPUT_KEYS and not key.startswith("_"):
                 payload[key] = value
         if record.exc_info:
             payload["exc_info"] = self.formatException(record.exc_info)