diff --git a/src/fairseq2/metrics/recorders/descriptor.py b/src/fairseq2/metrics/recorders/descriptor.py
index 9def7254c..6b716a118 100644
--- a/src/fairseq2/metrics/recorders/descriptor.py
+++ b/src/fairseq2/metrics/recorders/descriptor.py
@@ -17,6 +17,11 @@ def __call__(self, value: object) -> str: ...
 
 @dataclass
 class MetricDescriptor:
+    """
+    Represents a description of a metric including high level name,
+    name to display, and formatting
+    """
+
     name: str
     display_name: str
     priority: int
@@ -32,8 +37,15 @@ class MetricDescriptor:
 
 @final
 class MetricDescriptorRegistry:
+    """
+    Represents a way to store descriptors for multiple metrics in a composite metric
+    """
+
     def __init__(self, descriptors: Iterable[MetricDescriptor]) -> None:
         self._descriptors = {d.name: d for d in descriptors}
 
     def maybe_get(self, name: str) -> MetricDescriptor | None:
+        """
+        Returns a metric descriptor if it exists
+        """
         return self._descriptors.get(name)
diff --git a/src/fairseq2/metrics/recorders/jsonl.py b/src/fairseq2/metrics/recorders/jsonl.py
index 58c6619f2..bc56022f6 100644
--- a/src/fairseq2/metrics/recorders/jsonl.py
+++ b/src/fairseq2/metrics/recorders/jsonl.py
@@ -27,7 +27,7 @@
 
 @final
 class JsonlMetricRecorder(MetricRecorder):
-    """Records metric values to JSONL files."""
+    """Records metric values to JSONL files"""
 
     _CATEGORY_PART_REGEX: Final = re.compile("^[-_a-zA-Z0-9]+$")
 
diff --git a/src/fairseq2/metrics/recorders/log.py b/src/fairseq2/metrics/recorders/log.py
index 0aef7be76..1342f5ecc 100644
--- a/src/fairseq2/metrics/recorders/log.py
+++ b/src/fairseq2/metrics/recorders/log.py
@@ -32,6 +32,12 @@ def __init__(self, metric_descriptors: MetricDescriptorRegistry) -> None:
     def record_metric_values(
         self, category: str, values: Mapping[str, object], step_nr: int | None = None
     ) -> None:
+        """
+        Retrieves names, descriptors, and values for all metrics from a :class:`Mapping`.
+        Stores and sorts (values, descriptors) as ``tuples`` and formats a ``str``
+        with | separated tabular values. Splits metrics into multiple category parts
+        where they exist.
+        """
         if not log.is_enabled_for_info():
             return
 
@@ -81,4 +87,7 @@ def record_metric_values(
 
     @override
     def close(self) -> None:
+        """
+        Close the :class:`LogMetricRecorder`
+        """
         pass
diff --git a/src/fairseq2/metrics/recorders/tensorboard.py b/src/fairseq2/metrics/recorders/tensorboard.py
index 14e88d7c7..42f653962 100644
--- a/src/fairseq2/metrics/recorders/tensorboard.py
+++ b/src/fairseq2/metrics/recorders/tensorboard.py
@@ -51,6 +51,13 @@ def __init__(
     def record_metric_values(
         self, category: str, values: Mapping[str, object], step_nr: int | None = None
     ) -> None:
+        """
+        Retrieves TensorBoard :class:`SummaryWriter` ``objects`` for the metric scalars.
+        Maps descriptors to metric, step number, name, and scalar value and
+        flushes output
+        :raises OSError: If an operational system error occurs (FileNotFound, PermissionError, ConnectionError)
+        :raises RuntimeError: If the values cannot be written
+        """
         writer = self._get_writer(category)
 
         try:
@@ -74,6 +81,11 @@ def record_metric_values(
     def _add_value(
         self, writer: SummaryWriter, step_nr: int | None, name: str, value: object
     ) -> None:
+        """
+        Adds a `value` ``object`` to the `SummaryWriter`.
+        Can be text, a scalar, or torch Tensor
+        :raises ValueError: If `value` is not of type `int`, `float`, `Tensor` or `str`
+        """
         if isinstance(value, str):
             writer.add_text(name, value, step_nr)
 
@@ -95,6 +107,10 @@ def _add_value(
         )
 
     def _get_writer(self, category: str) -> SummaryWriter:
+        """
+        Instantiates a `SummaryWriter` and adds it to the ``writers`` `dict`
+        Stores `writer` under its category as key
+        """
         writer = self._writers.get(category)
         if writer is None:
             path = self._output_dir.joinpath(category)
@@ -107,6 +123,9 @@ def _get_writer(self, category: str) -> SummaryWriter:
 
     @override
     def close(self) -> None:
+        """
+        Close out and destroy every ``writer``
+        """
         for writer in self._writers.values():
             writer.close()
 
diff --git a/src/fairseq2/metrics/recorders/wandb.py b/src/fairseq2/metrics/recorders/wandb.py
index c852dfd8d..c2a114120 100644
--- a/src/fairseq2/metrics/recorders/wandb.py
+++ b/src/fairseq2/metrics/recorders/wandb.py
@@ -40,6 +40,11 @@ def __init__(
     def record_metric_values(
         self, category: str, values: Mapping[str, object], step_nr: int | None = None
     ) -> None:
+        """
+        Retrieves and stores a `descriptor` and `value` as a ``Mapping`` for each metric
+        :raises OSError: If an operational system error occurs (file not found, permission issue, connection problem)
+        :raises RuntimeError: If unable to write the metrics to wandb
+        """
         output: dict[str, object] = {}
 
         for name, value in values.items():
@@ -61,6 +66,10 @@ def record_metric_values(
             ) from ex
 
     def _add_value(self, name: str, value: object, output: dict[str, object]) -> None:
+        """
+        Adds a value to the output dictionary
+        :raises ValueError: If `values` are not of type int, float, Tensor or str
+        """
         if isinstance(value, (int, float, Tensor, str)):
             output[name] = value
 
@@ -78,4 +87,7 @@ def _add_value(self, name: str, value: object, output: dict[str, object]) -> Non
 
     @override
     def close(self) -> None:
+        """
+        Close wandb logger and end run
+        """
         self._run.finish()