diff --git a/src/gateway/protocol/cron-validators.test.ts b/src/gateway/protocol/cron-validators.test.ts
new file mode 100644
index 00000000000..13fc84a5944
--- /dev/null
+++ b/src/gateway/protocol/cron-validators.test.ts
@@ -0,0 +1,49 @@
+import { describe, expect, it } from "vitest";
+import {
+  validateCronAddParams,
+  validateCronRemoveParams,
+  validateCronRunParams,
+  validateCronRunsParams,
+  validateCronUpdateParams,
+} from "./index.js";
+
+const minimalAddParams = {
+  name: "daily-summary",
+  schedule: { kind: "every", everyMs: 60_000 },
+  sessionTarget: "main",
+  wakeMode: "next-heartbeat",
+  payload: { kind: "systemEvent", text: "tick" },
+} as const;
+
+describe("cron protocol validators", () => {
+  it("accepts minimal add params", () => {
+    expect(validateCronAddParams(minimalAddParams)).toBe(true);
+  });
+
+  it("rejects add params when required scheduling fields are missing", () => {
+    const { wakeMode: _wakeMode, ...withoutWakeMode } = minimalAddParams;
+    expect(validateCronAddParams(withoutWakeMode)).toBe(false);
+  });
+
+  it("accepts update params for id and jobId selectors", () => {
+    expect(validateCronUpdateParams({ id: "job-1", patch: { enabled: false } })).toBe(true);
+    expect(validateCronUpdateParams({ jobId: "job-2", patch: { enabled: true } })).toBe(true);
+  });
+
+  it("accepts remove params for id and jobId selectors", () => {
+    expect(validateCronRemoveParams({ id: "job-1" })).toBe(true);
+    expect(validateCronRemoveParams({ jobId: "job-2" })).toBe(true);
+  });
+
+  it("accepts run params mode for id and jobId selectors", () => {
+    expect(validateCronRunParams({ id: "job-1", mode: "force" })).toBe(true);
+    expect(validateCronRunParams({ jobId: "job-2", mode: "due" })).toBe(true);
+  });
+
+  it("enforces runs limit minimum for id and jobId selectors", () => {
+    expect(validateCronRunsParams({ id: "job-1", limit: 1 })).toBe(true);
+    expect(validateCronRunsParams({ jobId: "job-2", limit: 1 })).toBe(true);
+    expect(validateCronRunsParams({ id: "job-1", limit: 0 })).toBe(false);
+    expect(validateCronRunsParams({ jobId: "job-2", limit: 0 })).toBe(false);
+  });
+});
diff --git a/src/gateway/protocol/schema/cron.ts b/src/gateway/protocol/schema/cron.ts
index 270ca4a7421..99672b05211 100644
--- a/src/gateway/protocol/schema/cron.ts
+++ b/src/gateway/protocol/schema/cron.ts
@@ -19,6 +19,35 @@ function cronAgentTurnPayloadSchema(params: { message: TSchema }) {
   );
 }
 
+const CronSessionTargetSchema = Type.Union([Type.Literal("main"), Type.Literal("isolated")]);
+const CronWakeModeSchema = Type.Union([Type.Literal("next-heartbeat"), Type.Literal("now")]);
+const CronCommonOptionalFields = {
+  agentId: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
+  sessionKey: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
+  description: Type.Optional(Type.String()),
+  enabled: Type.Optional(Type.Boolean()),
+  deleteAfterRun: Type.Optional(Type.Boolean()),
+};
+
+function cronIdOrJobIdParams(extraFields: Record<string, TSchema>) {
+  return Type.Union([
+    Type.Object(
+      {
+        id: NonEmptyString,
+        ...extraFields,
+      },
+      { additionalProperties: false },
+    ),
+    Type.Object(
+      {
+        jobId: NonEmptyString,
+        ...extraFields,
+      },
+      { additionalProperties: false },
+    ),
+  ]);
+}
+
 export const CronScheduleSchema = Type.Union([
   Type.Object(
     {
@@ -144,8 +173,8 @@ export const CronJobSchema = Type.Object(
     createdAtMs: Type.Integer({ minimum: 0 }),
     updatedAtMs: Type.Integer({ minimum: 0 }),
     schedule: CronScheduleSchema,
-    sessionTarget: Type.Union([Type.Literal("main"), Type.Literal("isolated")]),
-    wakeMode: Type.Union([Type.Literal("next-heartbeat"), Type.Literal("now")]),
+    sessionTarget: CronSessionTargetSchema,
+    wakeMode: CronWakeModeSchema,
     payload: CronPayloadSchema,
     delivery: Type.Optional(CronDeliverySchema),
     state: CronJobStateSchema,
@@ -165,14 +194,10 @@ export const CronStatusParamsSchema = Type.Object({}, { additionalProperties: fa
 export const CronAddParamsSchema = Type.Object(
   {
     name: NonEmptyString,
-    agentId: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
-    sessionKey: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
-    description: Type.Optional(Type.String()),
-    enabled: Type.Optional(Type.Boolean()),
-    deleteAfterRun: Type.Optional(Type.Boolean()),
+    ...CronCommonOptionalFields,
     schedule: CronScheduleSchema,
-    sessionTarget: Type.Union([Type.Literal("main"), Type.Literal("isolated")]),
-    wakeMode: Type.Union([Type.Literal("next-heartbeat"), Type.Literal("now")]),
+    sessionTarget: CronSessionTargetSchema,
+    wakeMode: CronWakeModeSchema,
     payload: CronPayloadSchema,
     delivery: Type.Optional(CronDeliverySchema),
   },
@@ -182,14 +207,10 @@ export const CronAddParamsSchema = Type.Object(
 export const CronJobPatchSchema = Type.Object(
   {
     name: Type.Optional(NonEmptyString),
-    agentId: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
-    sessionKey: Type.Optional(Type.Union([NonEmptyString, Type.Null()])),
-    description: Type.Optional(Type.String()),
-    enabled: Type.Optional(Type.Boolean()),
-    deleteAfterRun: Type.Optional(Type.Boolean()),
+    ...CronCommonOptionalFields,
     schedule: Type.Optional(CronScheduleSchema),
-    sessionTarget: Type.Optional(Type.Union([Type.Literal("main"), Type.Literal("isolated")])),
-    wakeMode: Type.Optional(Type.Union([Type.Literal("next-heartbeat"), Type.Literal("now")])),
+    sessionTarget: Type.Optional(CronSessionTargetSchema),
+    wakeMode: Type.Optional(CronWakeModeSchema),
     payload: Type.Optional(CronPayloadPatchSchema),
     delivery: Type.Optional(CronDeliveryPatchSchema),
     state: Type.Optional(Type.Partial(CronJobStateSchema)),
@@ -197,71 +218,19 @@ export const CronJobPatchSchema = Type.Object(
   { additionalProperties: false },
 );
 
-export const CronUpdateParamsSchema = Type.Union([
-  Type.Object(
-    {
-      id: NonEmptyString,
-      patch: CronJobPatchSchema,
-    },
-    { additionalProperties: false },
-  ),
-  Type.Object(
-    {
-      jobId: NonEmptyString,
-      patch: CronJobPatchSchema,
-    },
-    { additionalProperties: false },
-  ),
-]);
+export const CronUpdateParamsSchema = cronIdOrJobIdParams({
+  patch: CronJobPatchSchema,
+});
 
-export const CronRemoveParamsSchema = Type.Union([
-  Type.Object(
-    {
-      id: NonEmptyString,
-    },
-    { additionalProperties: false },
-  ),
-  Type.Object(
-    {
-      jobId: NonEmptyString,
-    },
-    { additionalProperties: false },
-  ),
-]);
+export const CronRemoveParamsSchema = cronIdOrJobIdParams({});
 
-export const CronRunParamsSchema = Type.Union([
-  Type.Object(
-    {
-      id: NonEmptyString,
-      mode: Type.Optional(Type.Union([Type.Literal("due"), Type.Literal("force")])),
-    },
-    { additionalProperties: false },
-  ),
-  Type.Object(
-    {
-      jobId: NonEmptyString,
-      mode: Type.Optional(Type.Union([Type.Literal("due"), Type.Literal("force")])),
-    },
-    { additionalProperties: false },
-  ),
-]);
+export const CronRunParamsSchema = cronIdOrJobIdParams({
+  mode: Type.Optional(Type.Union([Type.Literal("due"), Type.Literal("force")])),
+});
 
-export const CronRunsParamsSchema = Type.Union([
-  Type.Object(
-    {
-      id: NonEmptyString,
-      limit: Type.Optional(Type.Integer({ minimum: 1, maximum: 5000 })),
-    },
-    { additionalProperties: false },
-  ),
-  Type.Object(
-    {
-      jobId: NonEmptyString,
-      limit: Type.Optional(Type.Integer({ minimum: 1, maximum: 5000 })),
-    },
-    { additionalProperties: false },
-  ),
-]);
+export const CronRunsParamsSchema = cronIdOrJobIdParams({
+  limit: Type.Optional(Type.Integer({ minimum: 1, maximum: 5000 })),
+});
 
 export const CronRunLogEntrySchema = Type.Object(
   {