diff --git a/agents/drivers/mongodb/src/main/java/com/dbx/agent/mongodb/MongoAgent.java b/agents/drivers/mongodb/src/main/java/com/dbx/agent/mongodb/MongoAgent.java
index a3d004f7f..cf2453e49 100644
--- a/agents/drivers/mongodb/src/main/java/com/dbx/agent/mongodb/MongoAgent.java
+++ b/agents/drivers/mongodb/src/main/java/com/dbx/agent/mongodb/MongoAgent.java
@@ -906,10 +906,9 @@ public final class MongoAgent {
             return converted;
         }
         if (value instanceof String text) {
+            // Plain JSON strings must retain their BSON type; only explicit shell date syntax
+            // is converted here. Extended JSON $date values are decoded by Document.parse.
             Date date = parseMongoShellDate(text);
-            if (date == null) {
-                date = parseLegacyDateDisplay(text);
-            }
             return date == null ? value : date;
         }
         return value;
@@ -938,28 +937,6 @@ public final class MongoAgent {
         }
     }
 
-    static Date parseLegacyDateDisplay(String value) {
-        String trimmed = value.trim();
-        if (!trimmed.matches("\\d{4}-\\d{2}-\\d{2}[ T]\\d{2}:\\d{2}:\\d{2}(\\.\\d{1,3})?")) {
-            return null;
-        }
-        String normalized = trimmed.replace(' ', 'T');
-        int dot = normalized.indexOf('.');
-        if (dot < 0) {
-            normalized = normalized + ".000";
-        } else {
-            int millisStart = dot + 1;
-            int millisEnd = normalized.length();
-            normalized = normalized.substring(0, millisStart)
-                + String.format("%-3s", normalized.substring(millisStart, millisEnd)).replace(' ', '0');
-        }
-        try {
-            return Date.from(Instant.parse(normalized + "Z"));
-        } catch (Exception e) {
-            return null;
-        }
-    }
-
     private static Object dispatch(String method, JsonObject params) {
         return switch (method) {
             case AgentProtocol.METHOD_HANDSHAKE -> AgentProtocol.handshakeResult();
diff --git a/agents/drivers/mongodb/src/test/java/com/dbx/agent/mongodb/MongoAgentTest.java b/agents/drivers/mongodb/src/test/java/com/dbx/agent/mongodb/MongoAgentTest.java
index 65428267c..d09faa119 100644
--- a/agents/drivers/mongodb/src/test/java/com/dbx/agent/mongodb/MongoAgentTest.java
+++ b/agents/drivers/mongodb/src/test/java/com/dbx/agent/mongodb/MongoAgentTest.java
@@ -569,12 +569,52 @@ class MongoAgentTest {
     }
 
     @Test
-    void documentForWriteParsesLegacyDateDisplayStrings() {
-        Document doc = MongoAgent.documentForWrite("{\"$set\":{\"CreateDate\":\"2025-08-14 02:25:43.718\"}}");
+    void documentForWritePreservesDateShapedStrings() {
+        Document doc = MongoAgent.documentForWrite(
+            "{\"$set\":{\"CreateDate\":\"2025-08-14 02:25:43.718\"," +
+                "\"nested\":{\"updated\":\"2025-08-14T02:25:43\"}," +
+                "\"items\":[\"2025-08-14 02:25:43\"]}}"
+        );
 
         Document set = (Document) doc.get("$set");
-        assertTrue(set.get("CreateDate") instanceof Date);
-        assertEquals(1_755_138_343_718L, ((Date) set.get("CreateDate")).getTime());
+        assertEquals("2025-08-14 02:25:43.718", set.getString("CreateDate"));
+        assertEquals("2025-08-14T02:25:43", ((Document) set.get("nested")).getString("updated"));
+        assertEquals("2025-08-14 02:25:43", ((List<?>) set.get("items")).get(0));
+    }
+
+    @Test
+    void documentForWriteParsesExtendedJsonDates() {
+        Document doc = MongoAgent.documentForWrite(
+            "{\"created\":{\"$date\":\"2026-06-10T13:59:31.287Z\"}," +
+                "\"items\":[{\"updated\":{\"$date\":{\"$numberLong\":\"1781100000000\"}}}]}"
+        );
+
+        assertTrue(doc.get("created") instanceof Date);
+        Document item = (Document) ((List<?>) doc.get("items")).get(0);
+        assertTrue(item.get("updated") instanceof Date);
+    }
+
+    @Test
+    void updatePipelinePreservesStringsAndParsesExplicitDates() {
+        List<Document> pipeline = MongoAgent.updatePipelineForWrite(
+            "[{\"$set\":{\"label\":\"2025-08-14 02:25:43.718\"," +
+                "\"created\":\"ISODate(\\\"2026-06-10T13:59:31.287Z\\\")\"}}]"
+        );
+
+        Document set = (Document) pipeline.get(0).get("$set");
+        assertEquals("2025-08-14 02:25:43.718", set.getString("label"));
+        assertTrue(set.get("created") instanceof Date);
+    }
+
+    @Test
+    void filterDocumentsPreserveDateShapedStrings() {
+        Document filter = MongoAgent.documentForWrite(
+            "{\"created\":\"2025-08-14 02:25:43.718\"," +
+                "\"updated\":{\"$date\":\"2026-06-10T13:59:31.287Z\"}}"
+        );
+
+        assertEquals("2025-08-14 02:25:43.718", filter.getString("created"));
+        assertTrue(filter.get("updated") instanceof Date);
     }
 
     @Test