diff --git a/apps/desktop/src/components/grid/__tests__/DataGridBatchPasteFromCell.spec.ts b/apps/desktop/src/components/grid/__tests__/DataGridBatchPasteFromCell.spec.ts
index ccaaf0a969..8c4566198b 100644
--- a/apps/desktop/src/components/grid/__tests__/DataGridBatchPasteFromCell.spec.ts
+++ b/apps/desktop/src/components/grid/__tests__/DataGridBatchPasteFromCell.spec.ts
@@ -7,6 +7,8 @@ import { createPinia, setActivePinia } from "pinia";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import i18n from "@/i18n";
 import type { QueryResult } from "@/types/database";
+import type { CustomSaveHandler } from "@/composables/useDataGridEditor";
+import { buildMongoUpdateDocument } from "@/lib/mongo/mongoDocumentValues";
 import { TooltipProvider } from "@/components/ui/tooltip";
 
 vi.mock("@/composables/useDataGridColumnResize", async (importOriginal) => {
@@ -57,7 +59,16 @@ function defaultResult(): QueryResult {
   };
 }
 
-function mountGrid(options: { result?: QueryResult; quickEntry?: boolean; hideNullColumns?: boolean; readonlyColumnIndexes?: number[] } = {}) {
+interface MountGridOptions {
+  result?: QueryResult;
+  quickEntry?: boolean;
+  hideNullColumns?: boolean;
+  readonlyColumnIndexes?: number[];
+  databaseType?: "dameng" | "mongodb";
+  customSaveHandler?: CustomSaveHandler;
+}
+
+function mountGrid(options: MountGridOptions = {}) {
   const pinia = createPinia();
   setActivePinia(pinia);
   const settingsStore = useSettingsStore();
@@ -76,9 +87,10 @@ function mountGrid(options: { result?: QueryResult; quickEntry?: boolean; hideNu
             default: () =>
               h(DataGrid, {
                 result: gridResult,
-                databaseType: "dameng",
+                databaseType: options.databaseType ?? "dameng",
                 context: "table-data",
                 editable: true,
+                customSaveHandler: options.customSaveHandler,
                 readonlyColumnIndexes: options.readonlyColumnIndexes,
                 tableMeta: {
                   tableName: "paste_target",
@@ -419,6 +431,69 @@ describe("DataGrid multi-row paste from a blank cell", () => {
     expect(pendingRows(host)).toHaveLength(1);
   });
 
+  it("preserves an ordinary string when a Mongo column selection is pasted and saved", async () => {
+    const result: QueryResult = {
+      columns: ["_id", "status"],
+      rows: [
+        ["1", "pending"],
+        ["2", "queued"],
+      ],
+      affected_rows: 0,
+      execution_time_ms: 0,
+    };
+    const originals = [
+      { _id: "1", status: "pending" },
+      { _id: "2", status: "queued" },
+    ];
+    const updates: Array<Record<string, unknown>> = [];
+    const customSaveHandler: CustomSaveHandler = {
+      supportsInsert: false,
+      save: async ({ dirtyRows, columns }) => {
+        for (const [rowIndex, changes] of dirtyRows) {
+          updates.push(buildMongoUpdateDocument(changes, columns, originals[rowIndex]));
+        }
+      },
+    };
+    const { host } = mountGrid({ result, databaseType: "mongodb", customSaveHandler });
+    await settle();
+    await selectColumnHeader(host, 1);
+    await paste(host, "Y");
+    gridRoot(host).dispatchEvent(new KeyboardEvent("keydown", { bubbles: true, cancelable: true, ctrlKey: true, key: "s" }));
+    await settle();
+
+    expect(updates).toEqual([{ $set: { status: "Y" } }, { $set: { status: "Y" } }]);
+  });
+
+  it("keeps JSON-looking plain text when a Mongo column paste reaches a missing field", async () => {
+    const result: QueryResult = {
+      columns: ["_id", "status"],
+      rows: [
+        ["1", null],
+        ["2", null],
+      ],
+      affected_rows: 0,
+      execution_time_ms: 0,
+    };
+    const originals = [{ _id: "1" }, { _id: "2" }];
+    const updates: Array<Record<string, unknown>> = [];
+    const customSaveHandler: CustomSaveHandler = {
+      supportsInsert: false,
+      save: async ({ dirtyRows, columns }) => {
+        for (const [rowIndex, changes] of dirtyRows) {
+          updates.push(buildMongoUpdateDocument(changes, columns, originals[rowIndex]));
+        }
+      },
+    };
+    const { host } = mountGrid({ result, databaseType: "mongodb", customSaveHandler });
+    await settle();
+    await selectColumnHeader(host, 1);
+    await paste(host, "{plain text");
+    gridRoot(host).dispatchEvent(new KeyboardEvent("keydown", { bubbles: true, cancelable: true, ctrlKey: true, key: "s" }));
+    await settle();
+
+    expect(updates).toEqual([{ $set: { status: "{plain text" } }, { $set: { status: "{plain text" } }]);
+  });
+
   it("routes DOM and canvas cell gestures through the same selection preparation", () => {
     const source = readFileSync(resolve(process.cwd(), "apps/desktop/src/components/grid/DataGrid.vue"), "utf8");
     const domGesture = source.slice(source.indexOf('@mousedown="\n                          prepareDataCellMouseDown'), source.indexOf('@mouseenter="onCellMouseenter'));
diff --git a/apps/desktop/src/lib/mongo/mongoDocumentValues.ts b/apps/desktop/src/lib/mongo/mongoDocumentValues.ts
index 2fdc818110..a71963fd36 100644
--- a/apps/desktop/src/lib/mongo/mongoDocumentValues.ts
+++ b/apps/desktop/src/lib/mongo/mongoDocumentValues.ts
@@ -52,7 +52,9 @@ export function parseMongoDocumentInputValue(raw: MongoInputValue): unknown {
 
   const trimmed = raw.trim();
   if (trimmed === "NULL") return null;
-  if (/^(true|false|null)$/i.test(trimmed)) return JSON.parse(trimmed.toLowerCase());
+  if (/^true$/i.test(trimmed)) return true;
+  if (/^false$/i.test(trimmed)) return false;
+  if (/^null$/i.test(trimmed)) return null;
 
   const shellDate = mongoShellDateToExtendedJson(trimmed);
   if (shellDate !== trimmed) return shellDate;
@@ -68,7 +70,12 @@ export function parseMongoDocumentInputValue(raw: MongoInputValue): unknown {
   }
   if (/^-?\d+\.\d+$/.test(trimmed)) return Number(trimmed);
   if (trimmed.startsWith("{") || trimmed.startsWith("[") || trimmed.startsWith('"')) {
-    return mongoShellDateToExtendedJson(JSON.parse(trimmed));
+    try {
+      return mongoShellDateToExtendedJson(JSON.parse(trimmed));
+    } catch {
+      // JSON-shaped text is still valid user data when it is not valid JSON.
+      return raw;
+    }
   }
   return raw;
 }
diff --git a/packages/app-tests/mongoDocumentValues.test.ts b/packages/app-tests/mongoDocumentValues.test.ts
index ff0842f5d1..f0692641bf 100644
--- a/packages/app-tests/mongoDocumentValues.test.ts
+++ b/packages/app-tests/mongoDocumentValues.test.ts
@@ -61,6 +61,13 @@ test("preserves date-shaped Mongo strings instead of guessing Date", () => {
   assert.equal(parseMongoDocumentInputValue('"2025-08-14 02:25:43.718"'), "2025-08-14 02:25:43.718");
 });
 
+test("preserves plain text that only resembles Mongo JSON input", () => {
+  for (const value of ["{plain text", "[plain text", '"plain text']) {
+    assert.doesNotThrow(() => parseMongoDocumentInputValue(value));
+    assert.equal(parseMongoDocumentInputValue(value), value);
+  }
+});
+
 test("preserves existing date-shaped Mongo string fields on grid update", () => {
   const original = {
     _id: "1",