diff --git a/bosk-bson/src/main/java/works/bosk/bson/BsonFormatter.java b/bosk-bson/src/main/java/works/bosk/bson/BsonFormatter.java
index 9b36c529..33c45cc2 100644
--- a/bosk-bson/src/main/java/works/bosk/bson/BsonFormatter.java
+++ b/bosk-bson/src/main/java/works/bosk/bson/BsonFormatter.java
@@ -291,6 +291,15 @@ public enum DocumentFields {
 		/**
 		 * The location of this document's state within the conceptual giant document.
 		 * A pipe-separated list of BSON field names.
+		 *
+		 * <p>
+		 * We put the whole path in _id so that it will be present in change stream documents.
+		 */
+		_id,
+
+		/**
+		 * The {@link Path#urlEncoded() url encoded} {@link Path path} of the location of
+		 * this document's state within the bosk tree.
 		 */
 		path,
 
diff --git a/bosk-bson/src/main/java/works/bosk/bson/BsonSurgeon.java b/bosk-bson/src/main/java/works/bosk/bson/BsonSurgeon.java
index eb9a5b71..6ab596b2 100644
--- a/bosk-bson/src/main/java/works/bosk/bson/BsonSurgeon.java
+++ b/bosk-bson/src/main/java/works/bosk/bson/BsonSurgeon.java
@@ -68,10 +68,7 @@ public GraftPoint boundTo(Identifier id) {
 		}
 	}
 
-	/**
-	 * We put the whole path in _id so that it will be present in change stream documents
-	 */
-	private static final String BSON_PATH_FIELD = "_id";
+	private static final String BSON_PATH_FIELD = DocumentFields._id.name();
 
 	private static final String STATE_FIELD = DocumentFields.state.name();
 
@@ -197,7 +194,8 @@ private static BsonDocument lookup(BsonDocument entireDoc, List<String> segments
 	 *
 	 * <p>
 	 * <code>partsList</code> is a list of "instructions" for assembling a larger document.
-	 * Each part contains a {@link DocumentFields#path path} field containing a {@link BsonFormatter#docBsonPath BSON path}
+	 * Each part contains a {@link DocumentFields#_id _id} field containing
+	 * a {@link BsonFormatter#docBsonPath BSON path}
 	 * that indicates where that part fits into the larger document;
 	 * and a {@link DocumentFields#state state} field with the contents of the part.
 	 *