diff --git a/src/app/api/__tests__/copy-renwei.test.ts b/src/app/api/__tests__/copy-renwei.test.ts
new file mode 100644
index 0000000..b846ee5
--- /dev/null
+++ b/src/app/api/__tests__/copy-renwei.test.ts
@@ -0,0 +1,138 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+const llmMocks = vi.hoisted(() => ({
+  generateValidatedJson: vi.fn(),
+}));
+
+vi.mock("../../../lib/llm/client", async () => {
+  const actual = await vi.importActual<typeof import("../../../lib/llm/client")>(
+    "../../../lib/llm/client",
+  );
+  return {
+    ...actual,
+    generateValidatedJson: llmMocks.generateValidatedJson,
+  };
+});
+
+import { POST as optimizeCopy } from "../copy/renwei-optimize/route";
+
+describe("renwei copy optimization API route", () => {
+  const originalApiKey = process.env.API_ACCESS_KEY;
+  const originalAuthDisabled = process.env.API_AUTH_DISABLED;
+
+  beforeEach(() => {
+    process.env.API_ACCESS_KEY = "test-key";
+    process.env.API_AUTH_DISABLED = "false";
+  });
+
+  afterEach(() => {
+    process.env.API_ACCESS_KEY = originalApiKey;
+    process.env.API_AUTH_DISABLED = originalAuthDisabled;
+    llmMocks.generateValidatedJson.mockReset();
+  });
+
+  it("rejects requests without the access key", async () => {
+    const response = await optimizeCopy(
+      request(
+        {
+          source_text: "这是一段普通文案。",
+          intensity: "light",
+        },
+        { apiKey: null },
+      ),
+    );
+
+    expect(response.status).toBe(401);
+  });
+
+  it("returns 400 for empty source text", async () => {
+    const response = await optimizeCopy(
+      request({
+        source_text: "   ",
+        intensity: "light",
+      }),
+    );
+    const body = (await response.json()) as { error: string };
+
+    expect(response.status).toBe(400);
+    expect(body.error).toBe("请输入需要优化的文案");
+  });
+
+  it("returns structured copy optimization results", async () => {
+    llmMocks.generateValidatedJson.mockResolvedValueOnce({
+      optimized_text: "我把这段文案顺了一下。",
+      change_notes: [
+        {
+          original: "我把这段文案顺顺。",
+          revised: "我把这段文案顺了一下。",
+          reason: "修正重复表达。",
+          confidence: "confident",
+          revertible: false,
+        },
+      ],
+      ai_taste_checks: [
+        {
+          rule_id: "promotion_tone",
+          status: "pass",
+          evidence: "没有新增宣传腔。",
+          suggestion: "",
+        },
+      ],
+      warnings: [],
+    });
+
+    const response = await optimizeCopy(
+      request({
+        source_text: "我把这段文案顺顺。",
+        goal: "",
+        intensity: "light",
+        user_instructions: "保留口语。",
+      }),
+    );
+    const body = (await response.json()) as {
+      result: { optimized_text: string; change_notes: unknown[] };
+    };
+
+    expect(response.status).toBe(200);
+    expect(body.result.optimized_text).toBe("我把这段文案顺了一下。");
+    expect(body.result.change_notes).toHaveLength(1);
+    expect(llmMocks.generateValidatedJson).toHaveBeenCalledWith(
+      expect.objectContaining({
+        task: "renwei_copy_optimizer",
+      }),
+    );
+  });
+
+  it("surfaces LLM failures as a 502", async () => {
+    llmMocks.generateValidatedJson.mockRejectedValueOnce(
+      new Error("LLM response failed schema validation: optimized_text"),
+    );
+
+    const response = await optimizeCopy(
+      request({
+        source_text: "这是一段普通文案。",
+        intensity: "light",
+      }),
+    );
+    const body = (await response.json()) as { error: string };
+
+    expect(response.status).toBe(502);
+    expect(body.error).toBe(
+      "LLM response failed schema validation: optimized_text",
+    );
+  });
+});
+
+function request(body: unknown, options: { apiKey?: string | null } = {}) {
+  const headers: Record<string, string> = { "content-type": "application/json" };
+  const apiKey = options.apiKey === undefined ? "test-key" : options.apiKey;
+  if (apiKey) {
+    headers["x-api-key"] = apiKey;
+  }
+
+  return new Request("http://localhost/api/copy/renwei-optimize", {
+    method: "POST",
+    body: JSON.stringify(body),
+    headers,
+  });
+}
diff --git a/src/app/api/copy/renwei-optimize/route.ts b/src/app/api/copy/renwei-optimize/route.ts
new file mode 100644
index 0000000..2e33192
--- /dev/null
+++ b/src/app/api/copy/renwei-optimize/route.ts
@@ -0,0 +1,39 @@
+import { NextResponse } from "next/server";
+import { z } from "zod";
+
+import { requireApiAccess } from "../../../../lib/api/auth";
+import { copyOptimizationRequestSchema } from "../../../../lib/domain/validation";
+import { LlmValidationError } from "../../../../lib/llm/client";
+import { optimizeRenweiCopy } from "../../../../lib/workflow/renwei-copy-optimizer";
+
+export async function POST(request: Request) {
+  const access = requireApiAccess(request);
+  if (!access.ok) {
+    return access.response;
+  }
+
+  try {
+    const payload = copyOptimizationRequestSchema.parse(await request.json());
+    const result = await optimizeRenweiCopy(payload);
+    return NextResponse.json({ result });
+  } catch (error) {
+    return jsonError(error, getErrorStatus(error));
+  }
+}
+
+function jsonError(error: unknown, status: number) {
+  const message =
+    error instanceof z.ZodError
+      ? "请输入需要优化的文案"
+      : error instanceof Error
+        ? error.message
+        : "文案优化失败";
+
+  return NextResponse.json({ error: message }, { status });
+}
+
+function getErrorStatus(error: unknown) {
+  if (error instanceof LlmValidationError) return 502;
+  if (error instanceof Error && /^LLM\b|provider/i.test(error.message)) return 502;
+  return 400;
+}