docs: document self.log vs get_logger logging convention

AGENTS.md

@@ -124,7 +124,7 @@ Substitute the equivalent for whichever agent was used. The convention is "visib
 
 ### Logging
 
-Get loggers via `cosmos.log.get_logger`, not the stdlib `logging` module. This adds the `(astronomer-cosmos)` prefix when `rich_logging` is enabled and respects scoped log-level configuration.
+In library / module-level code, get loggers via `cosmos.log.get_logger`, not the stdlib `logging` module. This adds the `(astronomer-cosmos)` prefix when `rich_logging` is enabled and respects scoped log-level configuration.
 
 Yes:
 ```python
@@ -141,6 +141,12 @@ logger = logging.getLogger(__name__)
 logging.error(...)  # never call the root logger directly either
 ```
 
+Inside operators, log via `self.log` (provided by Airflow's `LoggingMixin`) rather than a module-level logger, so messages land in the per-task-instance log shown in the Airflow UI:
+```python
+def execute(self, context):
+    self.log.info("Running command: %s", self.command)
+```
+
 Use **lazy logging**: pass the format string and arguments separately. Do not embed f-strings, `.format()`, or `%` interpolation in log messages — the logger formats them only when the record passes the level filter.
 
 Yes: