diff --git a/src/agents/tools/cron-tool.test.ts b/src/agents/tools/cron-tool.test.ts
index efab4535f..e53a87f1f 100644
--- a/src/agents/tools/cron-tool.test.ts
+++ b/src/agents/tools/cron-tool.test.ts
@@ -89,6 +89,33 @@ describe("cron tool", () => {
     });
   });
 
+  it("accepts cron.add job payloads as JSON strings", async () => {
+    const tool = createCronTool();
+    const jobJson = JSON.stringify({
+      name: "wake-up",
+      schedule: { atMs: 123 },
+      payload: { kind: "systemEvent", text: "hello" },
+    });
+    await tool.execute("call-json", {
+      action: "add",
+      job: jobJson,
+    });
+
+    expect(callGatewayMock).toHaveBeenCalledTimes(1);
+    const call = callGatewayMock.mock.calls[0]?.[0] as {
+      method?: string;
+      params?: unknown;
+    };
+    expect(call.method).toBe("cron.add");
+    expect(call.params).toEqual({
+      name: "wake-up",
+      schedule: { kind: "at", atMs: 123 },
+      sessionTarget: "main",
+      wakeMode: "next-heartbeat",
+      payload: { kind: "systemEvent", text: "hello" },
+    });
+  });
+
   it("does not default agentId when job.agentId is null", async () => {
     const tool = createCronTool({ agentSessionKey: "main" });
     await tool.execute("call-null", {
diff --git a/src/agents/tools/cron-tool.ts b/src/agents/tools/cron-tool.ts
index a1d218dd7..dfa974667 100644
--- a/src/agents/tools/cron-tool.ts
+++ b/src/agents/tools/cron-tool.ts
@@ -1,9 +1,9 @@
 import { Type } from "@sinclair/typebox";
-import { normalizeCronJobCreate, normalizeCronJobPatch } from "../../cron/normalize.js";
 import { loadConfig } from "../../config/config.js";
+import { normalizeCronJobCreate, normalizeCronJobPatch } from "../../cron/normalize.js";
 import { truncateUtf16Safe } from "../../utils.js";
-import { optionalStringEnum, stringEnum } from "../schema/typebox.js";
 import { resolveSessionAgentId } from "../agent-scope.js";
+import { optionalStringEnum, stringEnum } from "../schema/typebox.js";
 import { type AnyAgentTool, jsonResult, readStringParam } from "./common.js";
 import { callGatewayTool, type GatewayCallOptions } from "./gateway.js";
 import { resolveInternalSessionKey, resolveMainSessionAlias } from "./sessions-helpers.js";
@@ -155,10 +155,21 @@ export function createCronTool(opts?: CronToolOptions): AnyAgentTool {
             }),
           );
         case "add": {
-          if (!params.job || typeof params.job !== "object") {
+          if (params.job === null || params.job === undefined) {
             throw new Error("job required");
           }
-          const job = normalizeCronJobCreate(params.job) ?? params.job;
+          let rawJob: unknown = params.job;
+          if (typeof rawJob === "string") {
+            try {
+              rawJob = JSON.parse(rawJob);
+            } catch {
+              throw new Error("job must be object");
+            }
+          }
+          if (!rawJob || typeof rawJob !== "object" || Array.isArray(rawJob)) {
+            throw new Error("job must be object");
+          }
+          const job = normalizeCronJobCreate(rawJob) ?? rawJob;
           if (job && typeof job === "object" && !("agentId" in job)) {
             const cfg = loadConfig();
             const agentId = opts?.agentSessionKey