diff --git a/frontend/src/editor/graphAdapter.test.ts b/frontend/src/editor/graphAdapter.test.ts
index e42abe4..2cdbc8e 100644
--- a/frontend/src/editor/graphAdapter.test.ts
+++ b/frontend/src/editor/graphAdapter.test.ts
@@ -123,4 +123,44 @@ describe("toGraph — schema-typed coercion on save", () => {
     );
     expect(g.nodes[0].config.status).toBe(200);
   });
+
+  it("hex literals on integer fields are not coerced (backend rejects them too)", () => {
+    const g = toGraph(
+      [{
+        id: "n1", type: "vc",
+        position: { x: 0, y: 0 },
+        data: { typeId: "test.numberfield", config: { status: "0x1F" } },
+      }],
+      [],
+      [numberNodeType],
+    );
+    // Kept as string so backend surfaces the parse error at run time.
+    expect(g.nodes[0].config.status).toBe("0x1F");
+  });
+
+  it("scientific-notation strings on integer fields are not coerced (backend rejects them)", () => {
+    const g = toGraph(
+      [{
+        id: "n1", type: "vc",
+        position: { x: 0, y: 0 },
+        data: { typeId: "test.numberfield", config: { status: "1e2" } },
+      }],
+      [],
+      [numberNodeType],
+    );
+    expect(g.nodes[0].config.status).toBe("1e2");
+  });
+
+  it("scientific-notation strings on number fields ARE coerced (backend accepts them)", () => {
+    const g = toGraph(
+      [{
+        id: "n1", type: "vc",
+        position: { x: 0, y: 0 },
+        data: { typeId: "test.numberfield", config: { ratio: "1e2" } },
+      }],
+      [],
+      [numberNodeType],
+    );
+    expect(g.nodes[0].config.ratio).toBe(100);
+  });
 });
diff --git a/frontend/src/editor/graphAdapter.ts b/frontend/src/editor/graphAdapter.ts
index cdaba51..6012d55 100644
--- a/frontend/src/editor/graphAdapter.ts
+++ b/frontend/src/editor/graphAdapter.ts
@@ -79,11 +79,21 @@ export function coerceConfigForSave(
     }
     switch (prop.type) {
       case "integer": {
+        // Match backend long.TryParse(NumberStyles.Integer): sign + digits,
+        // optional leading/trailing whitespace. No hex, no scientific.
+        if (!/^\s*-?\d+\s*$/.test(value)) { out[name] = value; break; }
         const n = Number(value);
-        out[name] = Number.isInteger(n) ? n : value;
+        out[name] = Number.isSafeInteger(n) ? n : value;
         break;
       }
       case "number": {
+        // Match backend double.TryParse(NumberStyles.Float): sign + digits +
+        // optional fractional + optional exponent, optional whitespace.
+        // Rejects hex (`0x…`). Backend Float style accepts scientific
+        // notation, so we do too here.
+        if (!/^\s*-?(\d+\.?\d*|\.\d+)([eE][+-]?\d+)?\s*$/.test(value)) {
+          out[name] = value; break;
+        }
         const n = Number(value);
         out[name] = Number.isFinite(n) ? n : value;
         break;
diff --git a/frontend/src/pages/EditorPage.tsx b/frontend/src/pages/EditorPage.tsx
index 5b97934..2b77dd4 100644
--- a/frontend/src/pages/EditorPage.tsx
+++ b/frontend/src/pages/EditorPage.tsx
@@ -70,7 +70,7 @@ export default function EditorPage() {
     () =>
       apiFetch<void>(`/api/workflows/${id}`, {
         method: "PUT",
-        body: { name: wf.data!.name, graph: toGraph(nodes, edges) },
+        body: { name: wf.data!.name, graph: toGraph(nodes, edges, nts.data ?? []) },
       }),
     { onSuccess: () => id && invalidate(qk.workflow(id)) },
   );