diff --git a/verifiers/v1/trace.py b/verifiers/v1/trace.py
index cf2eda1cb..a07c24d75 100644
--- a/verifiers/v1/trace.py
+++ b/verifiers/v1/trace.py
@@ -404,6 +404,10 @@ class Trace(BaseModel, Generic[DataT, StateT, AgentConfigT]):
     preceding error)."""
     metrics: dict[str, float | None] = Field(default_factory=dict)
     """Unweighted, named metrics; `None` as in `rewards`."""
+    reward_shaping: dict[str, float] = Field(default_factory=dict)
+    """Additive training-reward terms recorded by a consumer's reward shapers (a length
+    penalty, ...), keyed by shaper name. A training annotation like `MessageNode.advantages`:
+    `reward` stays the env's verdict; the trainer scores against `reward` plus these terms."""
     info: dict[str, Any] = Field(default_factory=dict)
     """Scratch space for task-specific metadata."""
     state: StateT = Field(default_factory=State, exclude=True)