diff --git a/packages/commands/src/commands/auth/login.ts b/packages/commands/src/commands/auth/login.ts
index ca6752c..f7709a5 100644
--- a/packages/commands/src/commands/auth/login.ts
+++ b/packages/commands/src/commands/auth/login.ts
@@ -5,7 +5,6 @@ import {
   type Config,
   type GlobalFlags,
 } from "bailian-cli-core";
-import { IncompleteCommandError } from "bailian-cli-core";
 import { printQuickStart } from "bailian-cli-runtime";
 import { emitBare } from "bailian-cli-runtime";
 import {
@@ -31,6 +30,7 @@ export default defineCommand({
     },
   ],
   exampleArgs: ["--api-key sk-xxxxx", "--console"],
+  validate: (f) => (!f.console && !f.apiKey ? "Provide --api-key or --console" : undefined),
   async run(config: Config, flags: GlobalFlags) {
     if (flags.console) {
       if (config.dryRun) {
@@ -51,10 +51,7 @@ export default defineCommand({
       process.stderr.write(`Warning: DASHSCOPE_API_KEY is already set in environment.\n`);
     }
 
-    const key = (flags.apiKey as string) || config.apiKey;
-    if (!key) {
-      throw new IncompleteCommandError("Missing required argument: --api-key");
-    }
+    const key = flags.apiKey as string;
 
     const baseUrl = (flags.baseUrl as string) || undefined;
     const effectiveConfig = baseUrl ? { ...config, baseUrl } : config;
diff --git a/packages/commands/src/commands/speech/synthesize.ts b/packages/commands/src/commands/speech/synthesize.ts
index ae9a07a..4da0ac2 100644
--- a/packages/commands/src/commands/speech/synthesize.ts
+++ b/packages/commands/src/commands/speech/synthesize.ts
@@ -14,7 +14,6 @@ import {
   type OutputFormat,
   speechSynthesizeEndpoint,
   parseSSE,
-  IncompleteCommandError,
   resolveOutputDir,
   request,
   DOCS_HOSTS,
@@ -207,9 +206,8 @@ export default defineCommand({
       return;
     }
 
-    let text = flags.text as string | undefined;
-
-    // --text-file takes precedence if provided and --text is empty
+    // --text / --text-file presence enforced by validate; empty file content → API rejects.
+    let text = (flags.text as string) || "";
     if (!text && flags.textFile) {
       const filePath = flags.textFile as string;
       try {
@@ -218,10 +216,6 @@ export default defineCommand({
         throw new BailianError(`Cannot read text file: ${filePath}`, ExitCode.USAGE);
       }
     }
-
-    if (!text) {
-      throw new IncompleteCommandError("Provide --text or --text-file.");
-    }
     const voice = flags.voice as string;
 
     const language = (flags.language as string) || undefined;
diff --git a/packages/core/src/errors/base.ts b/packages/core/src/errors/base.ts
index 04fb116..69d9abb 100644
--- a/packages/core/src/errors/base.ts
+++ b/packages/core/src/errors/base.ts
@@ -45,13 +45,7 @@ export class BailianError extends Error {
   }
 }
 
-/**
- * The user invoked the CLI in a structurally invalid way: unknown command path,
- * unknown/badly-typed flag, or a missing required argument. Always carries
- * {@link ExitCode.USAGE}. The runtime's error boundary recognises this type and
- * renders the relevant command's help before printing the message — so command
- * code never builds usage strings or prints help itself; it just throws this.
- */
+/** Invalid usage: unknown command, bad/unknown flag, missing required, failed validation. */
 export class UsageError extends BailianError {
   constructor(message: string, hint?: string) {
     super(message, ExitCode.USAGE, hint);
@@ -59,20 +53,6 @@ export class UsageError extends BailianError {
   }
 }
 
-/**
- * The command is *incomplete* — a valid prefix that stopped short (a missing
- * required flag / positional). Distinct from {@link UsageError} ("you typed
- * something wrong"): an incomplete command is not an error. The runtime's error
- * boundary renders that command's help and exits 0 — exactly like landing on a
- * command group with no subcommand. Carries {@link ExitCode.SUCCESS}.
- */
-export class IncompleteCommandError extends BailianError {
-  constructor(message: string) {
-    super(message, ExitCode.SUCCESS);
-    this.name = "IncompleteCommandError";
-  }
-}
-
 function serializeCause(cause: unknown): Record<string, unknown> | undefined {
   if (cause == null) return undefined;
   if (cause instanceof Error) {
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index d48357d..a6cc28b 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,4 +1,4 @@
-export { BailianError, UsageError, IncompleteCommandError } from "./errors/base.ts";
+export { BailianError, UsageError } from "./errors/base.ts";
 export { mapApiError, type ApiErrorBody } from "./errors/api.ts";
 export { ExitCode } from "./errors/codes.ts";
 
diff --git a/packages/core/src/types/command.ts b/packages/core/src/types/command.ts
index 5443766..68da64d 100644
--- a/packages/core/src/types/command.ts
+++ b/packages/core/src/types/command.ts
@@ -47,12 +47,10 @@ export interface Command {
   auth: AuthRequirement;
   notes?: string[];
   /**
-   * Cross-flag validation, run after parsing and before execute. Return an
-   * error message when the flag combination is incomplete (one-of, 3-of-N,
-   * value-conditional, dependency, …); the runtime throws IncompleteCommandError
-   * and renders this command's help. Return undefined to pass. Single-flag
-   * `required: true` is enforced by the parser — use this only for rules that
-   * span multiple flags or depend on a flag's *value*.
+   * Cross-flag validation, run after parsing and before execute (one-of, 3-of-N,
+   * value-conditional, dependency, …). Return an error message → UsageError;
+   * undefined to pass. Single-flag `required: true` is enforced by the parser —
+   * use this only for rules spanning multiple flags or depending on a flag's *value*.
    */
   validate?: (flags: GlobalFlags) => string | undefined;
   execute: (config: Config, flags: GlobalFlags) => Promise<void>;
diff --git a/packages/runtime/src/args.ts b/packages/runtime/src/args.ts
index 7e47a7f..6b1d229 100644
--- a/packages/runtime/src/args.ts
+++ b/packages/runtime/src/args.ts
@@ -1,6 +1,6 @@
 import type { GlobalFlags } from "bailian-cli-core";
 import type { OptionDef } from "bailian-cli-core";
-import { UsageError, IncompleteCommandError } from "bailian-cli-core";
+import { UsageError } from "bailian-cli-core";
 
 function kebabToCamel(str: string): string {
   return str.replace(/-([a-z])/g, (_, c: string) => c.toUpperCase());
@@ -92,10 +92,8 @@ export function parsePath(argv: string[]): ParsePathResult {
 
 /**
  * Second pass — parse the flag region into typed values, driven entirely by the
- * OptionDef schema. Pure: returns typed flags or throws — never prints/exits.
- * The runtime's error boundary decides rendering. Throws IncompleteCommandError
- * for missing required flags (incomplete → help) and UsageError for malformed
- * input (unknown/short flag, bad value, unexpected token, duplicate).
+ * OptionDef schema. Pure: returns typed flags or throws UsageError — never
+ * prints/exits. The runtime's error boundary decides rendering.
  */
 export function parseFlags(rest: string[], options: OptionDef[]): GlobalFlags {
   const allowedKeys = buildAllowedFlagKeys(options);
@@ -189,7 +187,7 @@ export function parseFlags(rest: string[], options: OptionDef[]): GlobalFlags {
   });
   if (missing.length > 0) {
     const names = missing.map((opt) => opt.flag.match(/^(--[a-z][a-z0-9-]*)/i)?.[1] ?? opt.flag);
-    throw new IncompleteCommandError(
+    throw new UsageError(
       `Missing required ${names.length > 1 ? "flags" : "flag"}: ${names.join(", ")}`,
     );
   }
diff --git a/packages/runtime/src/create-cli.ts b/packages/runtime/src/create-cli.ts
index 6502cd3..bf9b259 100644
--- a/packages/runtime/src/create-cli.ts
+++ b/packages/runtime/src/create-cli.ts
@@ -10,12 +10,7 @@ import {
   type RunContext,
 } from "./middleware.ts";
 import type { Command, Config, GlobalFlags } from "bailian-cli-core";
-import {
-  GLOBAL_OPTIONS,
-  IncompleteCommandError,
-  loadConfig,
-  flushTelemetry,
-} from "bailian-cli-core";
+import { GLOBAL_OPTIONS, UsageError, loadConfig, flushTelemetry } from "bailian-cli-core";
 import { setupProxyFromEnv } from "./proxy.ts";
 import { handleError } from "./error-handler.ts";
 import { printWelcomeBanner, printQuickStart } from "./output/banner.ts";
@@ -37,12 +32,9 @@ export interface Cli {
 }
 
 /**
- * Build a CLI from an injected command set. The kernel is agnostic to *which*
- * commands exist — each product (bailian-cli, rag-cli, …) passes its own map and
- * identity. `run` is a thin orchestrator: resolve argv into a {@link Resolution},
- * then dispatch — terminal kinds render and return; `run` enters the middleware
- * stack guarded by a single error boundary. No business `if`s, no scattered
- * `process.exit`.
+ * Build a CLI from an injected command set — each product (bl / rag / …) passes
+ * its own commands + identity. `run` resolves argv into a {@link Resolution},
+ * then dispatches it.
  */
 export function createCli(commands: Record<string, Command>, opts: CliOptions): Cli {
   const registry = new CommandRegistry(commands, opts.binName);
@@ -117,9 +109,12 @@ export function createCli(commands: Record<string, Command>, opts: CliOptions):
 
       case "run": {
         try {
+          // 解析 flag + 跨 flag 校验：任何用法问题都抛 UsageError
           const flags = parseFlags(res.rest, [...GLOBAL_OPTIONS, ...(res.command.options ?? [])]);
           const invalid = res.command.validate?.(flags);
-          if (invalid) throw new IncompleteCommandError(invalid);
+          if (invalid) throw new UsageError(invalid);
+
+          // 校验通过 → 准备配置、进中间件执行命令
           const config = buildConfig(flags);
           const ctx: RunContext = {
             binName,
@@ -133,11 +128,13 @@ export function createCli(commands: Record<string, Command>, opts: CliOptions):
           await runMiddleware(ctx);
           await flushTelemetry(1000);
         } catch (err) {
-          await flushTelemetry(1000);
-          if (err instanceof IncompleteCommandError) {
+          // 裸调用（命令后什么都没写）下的 UsageError → 当"还没写完"，打 help、exit 0；
+          // 写了 flag 却无效、或执行时报错 → 报错、exit 2。
+          if (err instanceof UsageError && res.rest.length === 0) {
             registry.printHelp(res.path, process.stderr);
             return;
           }
+          await flushTelemetry(1000);
           handleError(err, binName);
         }
         return;
diff --git a/packages/runtime/src/output/output.ts b/packages/runtime/src/output/output.ts
index 54de51a..04c3037 100644
--- a/packages/runtime/src/output/output.ts
+++ b/packages/runtime/src/output/output.ts
@@ -2,13 +2,8 @@ import { formatOutput, type OutputFormat } from "bailian-cli-core";
 
 /**
  * Emit the primary result of a command.
- *
- * Design principle:
- *   stdout  → structured data only (JSON when piped, text when TTY)
- *   stderr  → human info (progress, logs, tips) — handled elsewhere
- *
- * This ensures `bl cmd ... | jq .` always receives clean JSON,
- * while interactive users see human-readable text.
+ *   stdout → result (text by default; JSON with --output json)
+ *   stderr → human info (progress, logs, tips) — handled elsewhere
  */
 export function emitResult(data: unknown, format: OutputFormat): void {
   process.stdout.write(formatOutput(data, format) + "\n");
diff --git a/packages/runtime/tests/args.test.ts b/packages/runtime/tests/args.test.ts
index 5b78bcd..938e24c 100644
--- a/packages/runtime/tests/args.test.ts
+++ b/packages/runtime/tests/args.test.ts
@@ -129,11 +129,11 @@ test("parseFlags validates number flags", () => {
   );
 });
 
-test("parseFlags throws IncompleteCommandError when a required flag is missing", () => {
+test("parseFlags throws UsageError when a required flag is missing", () => {
   expect(() => parseFlags(["--model", "qwen-image-2.0"], OPTS)).toThrowError(
     expect.objectContaining({
-      name: "IncompleteCommandError",
-      exitCode: ExitCode.SUCCESS,
+      name: "UsageError",
+      exitCode: ExitCode.USAGE,
       message: expect.stringContaining("Missing required flag: --prompt"),
     }),
   );