diff --git a/packages/commands/src/commands/knowledge/kb-stats.ts b/packages/commands/src/commands/knowledge/kb-stats.ts
index 275d651..45f7a8f 100644
--- a/packages/commands/src/commands/knowledge/kb-stats.ts
+++ b/packages/commands/src/commands/knowledge/kb-stats.ts
@@ -21,12 +21,13 @@ const KB_STATS_FLAGS = {
   start: {
     type: "string",
     valueHint: "<time>",
-    description: "Range start: Unix seconds or ISO date (default: 24 hours ago)",
+    description:
+      "Range start: Unix seconds or ISO date, must be in the past (default: 24 hours ago)",
   },
   end: {
     type: "string",
     valueHint: "<time>",
-    description: "Range end: Unix seconds or ISO date (default: now)",
+    description: "Range end: Unix seconds or ISO date, must be in the past (default: now)",
   },
   ...WORKSPACE_FLAG,
 } satisfies FlagsDef;
@@ -56,6 +57,7 @@ export default defineCommand({
   notes: [
     "Defaults to the last 24 hours when --start/--end are omitted.",
     "Timestamps are normalized to epoch seconds as required by the server.",
+    "Future timestamps are rejected for --start and clamped to now for --end, since the monitor API only returns past data.",
   ],
   exampleArgs: [
     "--index-id idx-xxx --workspace-id ws-xxx",
@@ -70,7 +72,21 @@ export default defineCommand({
     const startTimestamp = flags.start
       ? toEpochSecondsString(flags.start)
       : String(nowSeconds - 24 * 3600);
-    const endTimestamp = flags.end ? toEpochSecondsString(flags.end) : String(nowSeconds);
+    let endTimestamp = flags.end ? toEpochSecondsString(flags.end) : String(nowSeconds);
+
+    // The monitor API rejects future timestamps with a misleading
+    // "missing or invalid" error — validate here with a clear message.
+    if (Number(startTimestamp) > nowSeconds) {
+      throw new BailianError(
+        `Start time is in the future; the monitor API only accepts past or current timestamps.`,
+        ExitCode.USAGE,
+        "Use a start date/time at or before now, or omit --start to default to 24 hours ago.",
+      );
+    }
+    const clampedEnd = Number(endTimestamp) > nowSeconds;
+    if (clampedEnd) {
+      endTimestamp = String(nowSeconds);
+    }
 
     const body = { indexId: flags.indexId, startTimestamp, endTimestamp };
     const endpoint = ragEndpoint(workspaceId, RAG_PATHS.indexMonitor);
@@ -90,6 +106,9 @@ export default defineCommand({
       emitResult(response, format === "text" ? "json" : format);
       return;
     }
+    if (clampedEnd) {
+      emitBare("note: end time was in the future, clamped to now.");
+    }
     // Shape verified against the live API: the monitor fields are objects, not arrays
     const storage = response.data?.storageMonitorData;
     const qps = response.data?.qpsMonitorData;
diff --git a/packages/commands/tests/e2e/knowledge/knowledge-kb-stats.e2e.test.ts b/packages/commands/tests/e2e/knowledge/knowledge-kb-stats.e2e.test.ts
new file mode 100644
index 0000000..4e9fe29
--- /dev/null
+++ b/packages/commands/tests/e2e/knowledge/knowledge-kb-stats.e2e.test.ts
@@ -0,0 +1,95 @@
+import { describe, expect, test } from "vite-plus/test";
+import { parseStdoutJson, runCommandE2e } from "../helpers.ts";
+import { KNOWLEDGE_KB_STATS_ROUTES } from "../topic-routes.ts";
+
+interface DryRunBody {
+  endpoint?: string;
+  request?: {
+    indexId?: string;
+    startTimestamp?: string;
+    endTimestamp?: string;
+  };
+}
+
+describe("e2e: knowledge stats dry-run", () => {
+  test("--dry-run 正常日期范围输出正确时间戳", async () => {
+    const { stdout, stderr, exitCode } = await runCommandE2e(
+      KNOWLEDGE_KB_STATS_ROUTES,
+      [
+        "knowledge",
+        "stats",
+        "--dry-run",
+        "--index-id",
+        "idx_test",
+        "--start",
+        "2026-07-30",
+        "--end",
+        "2026-08-10",
+        "--workspace-id",
+        "ws_test",
+        "--output",
+        "json",
+      ],
+      { DASHSCOPE_API_KEY: "sk-fake-for-dryrun" },
+    );
+    expect(exitCode, stderr).toBe(0);
+    const data = parseStdoutJson<DryRunBody>(stdout);
+    expect(data.endpoint).toMatch(/api\/v1\/indices\/rag\/index\/monitor/);
+    expect(data.request?.indexId).toBe("idx_test");
+    expect(data.request?.startTimestamp).toBe("1785369600"); // 2026-07-30 00:00:00 UTC
+    expect(data.request?.endTimestamp).toBe("1786320000"); // 2026-08-10 00:00:00 UTC (11 days after start)
+  });
+
+  test("--end 未来时间被截断为当前时间", async () => {
+    const beforeRun = Math.floor(Date.now() / 1000);
+    const { stdout, stderr, exitCode } = await runCommandE2e(
+      KNOWLEDGE_KB_STATS_ROUTES,
+      [
+        "knowledge",
+        "stats",
+        "--dry-run",
+        "--index-id",
+        "idx_test",
+        "--start",
+        "2026-07-30",
+        "--end",
+        "2026-12-31",
+        "--workspace-id",
+        "ws_test",
+        "--output",
+        "json",
+      ],
+      { DASHSCOPE_API_KEY: "sk-fake-for-dryrun" },
+    );
+    const afterRun = Math.floor(Date.now() / 1000);
+    expect(exitCode, stderr).toBe(0);
+    const data = parseStdoutJson<DryRunBody>(stdout);
+    expect(data.request?.startTimestamp).toBe("1785369600"); // 2026-07-30 unchanged
+    // endTimestamp should be clamped to now, within the run window
+    const endTs = Number(data.request?.endTimestamp);
+    expect(endTs).toBeGreaterThanOrEqual(beforeRun);
+    expect(endTs).toBeLessThanOrEqual(afterRun);
+  });
+
+  test("--start 未来时间报用法错误 (exit 2)", async () => {
+    const { stderr, exitCode } = await runCommandE2e(
+      KNOWLEDGE_KB_STATS_ROUTES,
+      [
+        "knowledge",
+        "stats",
+        "--dry-run",
+        "--index-id",
+        "idx_test",
+        "--start",
+        "2026-12-31",
+        "--workspace-id",
+        "ws_test",
+        "--output",
+        "json",
+      ],
+      { DASHSCOPE_API_KEY: "sk-fake-for-dryrun" },
+    );
+    expect(exitCode).toBe(2);
+    expect(stderr).toMatch(/future/i);
+  });
+});
diff --git a/packages/commands/tests/e2e/topic-routes.ts b/packages/commands/tests/e2e/topic-routes.ts
index 84f81b4..cc8788c 100644
--- a/packages/commands/tests/e2e/topic-routes.ts
+++ b/packages/commands/tests/e2e/topic-routes.ts
@@ -244,6 +244,10 @@ export const KNOWLEDGE_DOC_TAG_ROUTES: E2eRouteExports = {
   "knowledge file delete": "knowledgeFileDelete", // live cleanup of data-center files
 };
 
+export const KNOWLEDGE_KB_STATS_ROUTES: E2eRouteExports = {
+  "knowledge stats": "knowledgeKbStats",
+};
+
 export const KNOWLEDGE_SERVICE_ROUTES: E2eRouteExports = {
   "knowledge service list": "knowledgeServiceList",
   "knowledge service get": "knowledgeServiceGet",
diff --git a/skills/bailian-cli/reference/knowledge.md b/skills/bailian-cli/reference/knowledge.md
index 05b54c7..2e13d8b 100644
--- a/skills/bailian-cli/reference/knowledge.md
+++ b/skills/bailian-cli/reference/knowledge.md
@@ -1207,19 +1207,20 @@ bl knowledge service update --agent-id aid-xxx --agent-version 1 --version-desc
 
 #### Flags
 
-| Flag                  | Type   | Required | Description                                                     |
-| --------------------- | ------ | -------- | --------------------------------------------------------------- |
-| `--index-id <id>`     | string | yes      | Knowledge base ID                                               |
-| `--start <time>`      | string | no       | Range start: Unix seconds or ISO date (default: 24 hours ago)   |
-| `--end <time>`        | string | no       | Range end: Unix seconds or ISO date (default: now)              |
-| `--workspace-id <id>` | string | no       | Workspace ID for API endpoint URL (or set BAILIAN_WORKSPACE_ID) |
-| `--api-key <key>`     | string | no       | API key                                                         |
-| `--base-url <url>`    | string | no       | API base URL                                                    |
+| Flag                  | Type   | Required | Description                                                                        |
+| --------------------- | ------ | -------- | ---------------------------------------------------------------------------------- |
+| `--index-id <id>`     | string | yes      | Knowledge base ID                                                                  |
+| `--start <time>`      | string | no       | Range start: Unix seconds or ISO date, must be in the past (default: 24 hours ago) |
+| `--end <time>`        | string | no       | Range end: Unix seconds or ISO date, must be in the past (default: now)            |
+| `--workspace-id <id>` | string | no       | Workspace ID for API endpoint URL (or set BAILIAN_WORKSPACE_ID)                    |
+| `--api-key <key>`     | string | no       | API key                                                                            |
+| `--base-url <url>`    | string | no       | API base URL                                                                       |
 
 #### Notes
 
 - Defaults to the last 24 hours when --start/--end are omitted.
 - Timestamps are normalized to epoch seconds as required by the server.
+- Future timestamps are rejected for --start and clamped to now for --end, since the monitor API only returns past data.
 
 #### Examples