Minor documentation cleanup

docs/integrations/dnd-spell-artifacts.md

@@ -19,7 +19,7 @@ the evidence location.
 
 ## Output Shape
 
-`lanes/spells.json` is a JSON object with one required top-level array. Its
+The extractor payload is a JSON object with one required top-level array. Its
 structure is:
 
 ```text
@@ -28,6 +28,9 @@ structure is:
 
 `spell_casts` must be present. It may be empty when no spell casts are found.
 When multiple chunk results are combined, spell casts remain in chunk order.
+When the payload is written as durable output, its logical path is derived from
+the configured artifact lane ID as defined by the
+[JSON output contract](json-output.md#output-payload-files).
 
 ## Spell-Cast Fields