diff --git a/src/cli/program/message/helpers.test.ts b/src/cli/program/message/helpers.test.ts
index e8f74637ffd..a4c929da45e 100644
--- a/src/cli/program/message/helpers.test.ts
+++ b/src/cli/program/message/helpers.test.ts
@@ -306,6 +306,116 @@ describe("runMessageAction", () => {
     expect(exitMock).not.toHaveBeenCalledWith(0);
   });
 
+  it.each([
+    [
+      "poll duration hours",
+      "poll",
+      {
+        channel: "discord",
+        target: "123",
+        pollQuestion: "ship?",
+        pollOption: ["yes", "no"],
+        pollDurationHours: "1.5",
+      },
+      "--poll-duration-hours",
+    ],
+    [
+      "poll duration seconds",
+      "poll",
+      {
+        channel: "telegram",
+        target: "123",
+        pollQuestion: "ship?",
+        pollOption: ["yes", "no"],
+        pollDurationSeconds: "60s",
+      },
+      "--poll-duration-seconds",
+    ],
+    [
+      "timeout duration",
+      "timeout",
+      { guildId: "g", userId: "u", durationMin: "5m" },
+      "--duration-min",
+    ],
+    ["ban delete days", "ban", { guildId: "g", userId: "u", deleteDays: "7d" }, "--delete-days"],
+    ["read limit", "read", { channel: "discord", target: "123", limit: "10x" }, "--limit"],
+    ["search limit", "search", { guildId: "g", query: "hello", limit: "10x" }, "--limit"],
+    ["pins limit", "list-pins", { channel: "discord", target: "123", limit: "10x" }, "--limit"],
+    [
+      "reactions limit",
+      "reactions",
+      { channel: "discord", target: "123", messageId: "m", limit: "10x" },
+      "--limit",
+    ],
+    [
+      "thread auto archive minutes",
+      "thread-create",
+      {
+        channel: "discord",
+        target: "123",
+        threadName: "ops",
+        autoArchiveMin: "60m",
+      },
+      "--auto-archive-min",
+    ],
+    ["thread list limit", "thread-list", { guildId: "g", limit: "10x" }, "--limit"],
+  ])("rejects malformed numeric CLI option for %s", async (_name, action, opts, flag) => {
+    const runMessageAction = createRunMessageAction();
+
+    await expect(runMessageAction(action, opts)).rejects.toThrow("exit");
+
+    const kind = flag === "--delete-days" ? "non-negative" : "positive";
+    expect(errorMock).toHaveBeenCalledWith(`Error: ${flag} must be a ${kind} integer.`);
+    expect(ensurePluginRegistryLoaded).not.toHaveBeenCalled();
+    expect(messageCommandMock).not.toHaveBeenCalled();
+    expect(exitMock).toHaveBeenCalledWith(1);
+    expect(exitMock).not.toHaveBeenCalledWith(0);
+  });
+
+  it.each([
+    ["pollDurationHours", "0", "--poll-duration-hours"],
+    ["pollDurationSeconds", "-1", "--poll-duration-seconds"],
+    ["durationMin", "", "--duration-min"],
+    ["deleteDays", Number.NaN, "--delete-days"],
+    ["limit", 1.2, "--limit"],
+    ["autoArchiveMin", null, "--auto-archive-min"],
+  ])("rejects non-positive or non-integer %s values", async (key, value, flag) => {
+    const runMessageAction = createRunMessageAction();
+
+    await expect(
+      runMessageAction("send", {
+        ...baseSendOptions,
+        [key]: value,
+      }),
+    ).rejects.toThrow("exit");
+
+    const kind = flag === "--delete-days" ? "non-negative" : "positive";
+    expect(errorMock).toHaveBeenCalledWith(`Error: ${flag} must be a ${kind} integer.`);
+    expect(messageCommandMock).not.toHaveBeenCalled();
+    expect(exitMock).toHaveBeenCalledWith(1);
+  });
+
+  it("allows zero delete-days for no-history Discord bans", async () => {
+    const runMessageAction = createRunMessageAction();
+
+    await expect(
+      runMessageAction("ban", {
+        guildId: "g",
+        userId: "u",
+        deleteDays: "0",
+      }),
+    ).rejects.toThrow("exit");
+
+    expect(errorMock).not.toHaveBeenCalled();
+    expectMessageCommandOptions({
+      action: "ban",
+      guildId: "g",
+      userId: "u",
+      deleteDays: "0",
+    });
+    expect(exitMock).toHaveBeenCalledWith(0);
+  });
+
   it("runs gateway_stop hooks before exit when registered", async () => {
     hasHooksMock.mockReturnValueOnce(true);
     await runSendAction();
diff --git a/src/cli/program/message/helpers.ts b/src/cli/program/message/helpers.ts
index def381c726f..739945a0eb0 100644
--- a/src/cli/program/message/helpers.ts
+++ b/src/cli/program/message/helpers.ts
@@ -8,6 +8,10 @@ import { resolveMessageSecretScope } from "../../../cli/message-secret-scope.js"
 import { messageCommand } from "../../../commands/message.js";
 import { danger, setVerbose } from "../../../globals.js";
 import { CHANNEL_TARGET_DESCRIPTION } from "../../../infra/outbound/channel-target.js";
+import {
+  parseStrictNonNegativeInteger,
+  parseStrictPositiveInteger,
+} from "../../../infra/parse-finite-number.js";
 import { runGlobalGatewayStopSafely } from "../../../plugins/hook-runner-global.js";
 import { defaultRuntime } from "../../../runtime.js";
 import { runCommandWithRuntime } from "../../cli-utils.js";
@@ -25,6 +29,14 @@ const GATEWAY_STOP_TIMEOUT_MS = 2500;
 const ACTIONS_WITHOUT_STOP_HOOKS = new Set(["read"]);
 const ACTIONS_REQUIRING_CONFIGURED_CHANNEL_PRELOAD = new Set(["broadcast"]);
 const CHANNEL_MESSAGE_ACTION_NAME_SET = new Set<string>(CHANNEL_MESSAGE_ACTION_NAMES);
+const STRICT_POSITIVE_INTEGER_OPTIONS = new Map([
+  ["pollDurationHours", "--poll-duration-hours"],
+  ["pollDurationSeconds", "--poll-duration-seconds"],
+  ["durationMin", "--duration-min"],
+  ["limit", "--limit"],
+  ["autoArchiveMin", "--auto-archive-min"],
+]);
+const STRICT_NON_NEGATIVE_INTEGER_OPTIONS = new Map([["deleteDays", "--delete-days"]]);
 
 type MessagePluginLoadOptions = { scope: PluginRegistryScope; onlyChannelIds?: string[] };
 type MessagePluginPreloadPlan =
@@ -39,6 +51,25 @@ function normalizeMessageOptions(opts: Record<string, unknown>): Record<string,
   };
 }
 
+function validateMessageNumericOptions(opts: Record<string, unknown>): void {
+  for (const [key, flag] of STRICT_POSITIVE_INTEGER_OPTIONS) {
+    if (opts[key] === undefined) {
+      continue;
+    }
+    if (parseStrictPositiveInteger(opts[key]) === undefined) {
+      throw new Error(`${flag} must be a positive integer.`);
+    }
+  }
+  for (const [key, flag] of STRICT_NON_NEGATIVE_INTEGER_OPTIONS) {
+    if (opts[key] === undefined) {
+      continue;
+    }
+    if (parseStrictNonNegativeInteger(opts[key]) === undefined) {
+      throw new Error(`${flag} must be a non-negative integer.`);
+    }
+  }
+}
+
 async function runPluginStopHooks(): Promise<void> {
   let timeout: NodeJS.Timeout | null = null;
   const hookRun = runGlobalGatewayStopSafely({
@@ -128,6 +159,7 @@ export function createMessageCliHelpers(
     await runCommandWithRuntime(
       defaultRuntime,
       async () => {
+        validateMessageNumericOptions(opts);
         const preloadPlan = resolveMessagePluginPreloadPlan(action, opts);
         if (preloadPlan.preload) {
           ensurePluginRegistryLoaded(preloadPlan.loadOptions);