diff --git a/apps/webapp/test/mollifierMollify.test.ts b/apps/webapp/test/mollifierMollify.test.ts
new file mode 100644
index 000000000..028ebd87c
--- /dev/null
+++ b/apps/webapp/test/mollifierMollify.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("~/db.server", () => ({
+  prisma: {},
+  $replica: {},
+}));
+
+import { mollifyTrigger } from "~/v3/mollifier/mollifierMollify.server";
+import type { MollifierBuffer } from "@trigger.dev/redis-worker";
+
+function fakeBuffer(): { buffer: MollifierBuffer; accept: ReturnType<typeof vi.fn> } {
+  const accept = vi.fn(async () => undefined);
+  return {
+    buffer: { accept } as unknown as MollifierBuffer,
+    accept,
+  };
+}
+
+describe("mollifyTrigger", () => {
+  it("writes the snapshot to buffer and returns synthesised result", async () => {
+    const { buffer, accept } = fakeBuffer();
+    const result = await mollifyTrigger({
+      runFriendlyId: "run_friendly_1",
+      environmentId: "env_a",
+      organizationId: "org_1",
+      engineTriggerInput: { taskIdentifier: "my-task", payload: '{"x":1}' },
+      decision: {
+        divert: true,
+        reason: "per_env_rate",
+        count: 150,
+        threshold: 100,
+      },
+      buffer,
+    });
+
+    expect(accept).toHaveBeenCalledOnce();
+    expect(accept).toHaveBeenCalledWith({
+      runId: "run_friendly_1",
+      envId: "env_a",
+      orgId: "org_1",
+      payload: expect.any(String),
+    });
+    expect(result.run.friendlyId).toBe("run_friendly_1");
+    expect(result.error).toBeUndefined();
+    expect(result.isCached).toBe(false);
+    expect(result.notice).toEqual({
+      code: "mollifier.queued",
+      message: expect.stringContaining("burst buffer"),
+      docs: expect.stringContaining("trigger.dev/docs"),
+    });
+  });
+
+  it("snapshot is round-trippable: payload field is parseable JSON of engineTriggerInput", async () => {
+    const { buffer, accept } = fakeBuffer();
+    const engineInput = { taskIdentifier: "t", payload: "{}", tags: ["a", "b"] };
+    await mollifyTrigger({
+      runFriendlyId: "run_x",
+      environmentId: "env_a",
+      organizationId: "org_1",
+      engineTriggerInput: engineInput,
+      decision: { divert: true, reason: "per_env_rate", count: 1, threshold: 1 },
+      buffer,
+    });
+
+    const callArg = accept.mock.calls[0][0] as { payload: string };
+    expect(JSON.parse(callArg.payload)).toEqual(engineInput);
+  });
+});