diff --git a/cspell.json b/cspell.json
index f220de4..24d7bb2 100644
--- a/cspell.json
+++ b/cspell.json
@@ -17,6 +17,7 @@
     "packagejson",
     "prefault",
     "preinstall",
+    "ptaas",
     "remeda",
     "traceparent",
     "tracestate",
diff --git a/examples/cozeloop-ai-node/src/practice/travel-plan.ts b/examples/cozeloop-ai-node/src/practice/travel-plan.ts
index c4a7eae..105b627 100644
--- a/examples/cozeloop-ai-node/src/practice/travel-plan.ts
+++ b/examples/cozeloop-ai-node/src/practice/travel-plan.ts
@@ -1,6 +1,6 @@
 import { type ChatCompletionCreateParams } from 'openai/resources/chat';
 import { OpenAI } from 'openai';
-import { cozeLoopTracer, PromptHub, SpanKind } from '@cozeloop/ai';
+import { cozeLoopTracer, PromptHub, type Span, SpanKind } from '@cozeloop/ai';
 
 // initialize tracer globally
 cozeLoopTracer.initialize({
@@ -23,7 +23,7 @@ async function callLLM(messages: ChatCompletionCreateParams['messages']) {
 
   // wrap model as a span node with `cozeLoopTracer.traceable`
   return await cozeLoopTracer.traceable(
-    async span => {
+    async (span: Span) => {
       cozeLoopTracer.setInput(span, { messages });
 
       const resp = await openai.chat.completions.create({
@@ -64,7 +64,7 @@ async function runTravelPlan(options: TravelPlanOptions) {
   const messages = hub.formatPrompt(prompt, { ...options });
 
   // invoke model
-  return callLLM(messages);
+  return callLLM(messages as ChatCompletionCreateParams['messages']);
 }
 
 async function run() {
@@ -77,7 +77,7 @@ async function run() {
   };
 
   const result = await cozeLoopTracer.traceable(
-    async span => {
+    async (span: Span) => {
       cozeLoopTracer.setInput(span, options);
       const { choices } = await runTravelPlan(options);
 
diff --git a/examples/cozeloop-ai-node/src/prompt/index.ts b/examples/cozeloop-ai-node/src/prompt/index.ts
index 509523d..a3b4331 100644
--- a/examples/cozeloop-ai-node/src/prompt/index.ts
+++ b/examples/cozeloop-ai-node/src/prompt/index.ts
@@ -1,6 +1,7 @@
 import { run as runMultiPart } from './with-multi-part';
 import { run as runWithLabel } from './with-label';
 import { run as runWithJinja } from './with-jinja';
+import { run as runPTaaS } from './ptaas';
 import { run as runBasic } from './hub';
 
 export async function run() {
@@ -9,6 +10,7 @@ export async function run() {
     runWithJinja(),
     runMultiPart(),
     runWithLabel(),
+    runPTaaS(),
   ]);
 
   process.exit(0);
diff --git a/examples/cozeloop-ai-node/src/prompt/ptaas.ts b/examples/cozeloop-ai-node/src/prompt/ptaas.ts
new file mode 100644
index 0000000..7cd6e32
--- /dev/null
+++ b/examples/cozeloop-ai-node/src/prompt/ptaas.ts
@@ -0,0 +1,132 @@
+import assert from 'node:assert';
+
+import { PromptAsAService } from '@cozeloop/ai';
+
+async function runWithNormal() {
+  const model = new PromptAsAService({
+    /** workspace id, use process.env.COZELOOP_WORKSPACE_ID when unprovided */
+    // workspaceId: 'your_workspace_id',
+    apiClient: {
+      // baseURL: 'api_base_url',
+      // token: 'your_api_token',
+    },
+    prompt: {
+      prompt_key: 'CozeLoop_Travel_Master',
+      version: '0.0.2',
+    },
+  });
+
+  // 1. model.invoke
+  const reply = await model.invoke({
+    messages: [{ role: 'user', content: '帮我规划轻松旅行' }],
+    variables: {
+      departure: '北京',
+      destination: '上海',
+      people_num: 2,
+      days_num: 1,
+      travel_theme: '亲子',
+    },
+  });
+
+  assert(reply?.message);
+  assert(reply.usage);
+  assert.strictEqual(reply.finish_reason, 'stop');
+
+  // 2. model.stream
+  const replyStream = await model.stream({
+    messages: [{ role: 'user', content: '帮我规划轻松旅行' }],
+    variables: {
+      departure: '北京',
+      destination: '上海',
+      people_num: 2,
+      days_num: 1,
+      travel_theme: '亲子',
+    },
+  });
+
+  for await (const chunk of replyStream) {
+    assert(chunk);
+  }
+}
+
+async function runWithJinja() {
+  const model = new PromptAsAService({
+    /** workspace id, use process.env.COZELOOP_WORKSPACE_ID when unprovided */
+    // workspaceId: 'your_workspace_id',
+    apiClient: {
+      // baseURL: 'api_base_url',
+      // token: 'your_api_token',
+    },
+    prompt: {
+      prompt_key: 'loop12',
+      version: '0.0.5',
+    },
+  });
+
+  // 1. model.invoke
+  const reply = await model.invoke({
+    messages: [{ role: 'user', content: '总结模板内容' }],
+    variables: {
+      title: 'Title',
+      user: {
+        is_authenticated: false,
+        name: 'Loop',
+      },
+      items: [{ name: 'fish' }],
+      place: [{ role: 'assistant', content: '好的' }],
+    },
+  });
+
+  assert(reply?.message);
+  assert(reply.usage);
+  assert.strictEqual(reply.finish_reason, 'stop');
+}
+
+async function runWithMultiPart() {
+  const model = new PromptAsAService({
+    /** workspace id, use process.env.COZELOOP_WORKSPACE_ID when unprovided */
+    // workspaceId: 'your_workspace_id',
+    apiClient: {
+      // baseURL: 'api_base_url',
+      // token: 'your_api_token',
+    },
+    prompt: {
+      prompt_key: 'loop',
+      version: '0.0.3',
+    },
+  });
+
+  const replyStream = await model.stream({
+    messages: [{ role: 'user', content: 'respond in 50 words' }],
+    variables: {
+      var1: 'sports',
+      placeholder1: { role: 'assistant', content: 'go on' },
+      var2: 'how to play football',
+      img1: [
+        { type: 'text', text: 'text1' },
+        {
+          type: 'image_url',
+          image_url: {
+            url: 'https://tinypng.com/static/images/george-anim/large_george_x2.webp',
+          },
+        },
+      ],
+    },
+  });
+
+  for await (const chunk of replyStream) {
+    assert(chunk);
+  }
+}
+
+export async function run() {
+  await Promise.all([
+    runWithNormal(), // 普通模板
+    runWithJinja(), // Jinja2 模板
+    runWithMultiPart(), // 多模态变量
+  ]);
+
+  process.exit();
+}
+
+run();
diff --git a/packages/cozeloop-ai/CHANGELOG.md b/packages/cozeloop-ai/CHANGELOG.md
index 38b0c8e..28ac329 100644
--- a/packages/cozeloop-ai/CHANGELOG.md
+++ b/packages/cozeloop-ai/CHANGELOG.md
@@ -1,5 +1,8 @@
 # 🕗 ChangeLog - @cozeloop/ai
 
+## 0.0.9
+* Prompt as a Service (ptaas)
+
 ## 0.0.8
 * PromptHub: get prompt with label
 
diff --git a/packages/cozeloop-ai/README.md b/packages/cozeloop-ai/README.md
index 5759485..2d2e864 100644
--- a/packages/cozeloop-ai/README.md
+++ b/packages/cozeloop-ai/README.md
@@ -19,30 +19,44 @@ pnpm install @cozeloop/ai
 
 ### 2. Basic Usage
 ```typescript
-import { ApiClient, PromptHub } from '@cozeloop/ai';
+import { ApiClient, PromptHub, PromptAsAService } from '@cozeloop/ai';
 
-// 1. setup API client
+// 1. Setup API client
 const apiClient = new ApiClient({
   baseURL: 'https://api.coze.cn',
   token: 'your_access_token',
 });
 
-// 2. Using prompt hub to get prompt
-const promptHub = new PromptHub({
+// 2. Using `PromptHub` or `PromptAsAService`
+const hub = new PromptHub({
   // or set it as process.env.COZELOOP_WORKSPACE_ID,
   workspaceId: 'your_workspace_id',
   apiClient,
 });
+// hub.getPrompt(key, version);
+// hub.formatPrompt(prompt);
 
-const prompt = await promptHub.getPrompt(
-  'your_prompt_key',
-  'prompt_version (optional)',
-);
+const model = new PromptAsAService({
+  // or set it as process.env.COZELOOP_WORKSPACE_ID,
+  workspaceId: 'your_workspace_id',
+  // prompt to invoke as a service
+  prompt: {
+    prompt_key: 'your_prompt_key',
+  },
+  apiClient,
+});
+// model.invoke({
+//   messages: [{ role: 'user', content: 'hi' }],
+// });
+// model.stream({
+//   messages: [{ role: 'user', content: 'hi' }],
+// });
 ```
 
 ## Key Features
-- 🗄️ **Prompt Hub**: Develop, submit and publish prompts on [CozeLoop](https://loop.coze.cn), and access them it via `PromptHub`
-- 🔐 **Authentication Methods**: PAT and JWT
+- 🗂️ **Prompt Hub**: Develop, submit and publish prompts on [CozeLoop](https://loop.coze.cn), and access them via `PromptHub`
+- 🛠️ **Prompt as a Service**: Develop, submit and publish prompts on [CozeLoop](https://loop.coze.cn), and invoke them as services
+- 🔐 **Authentication Methods**: PAT, SAT and JWT
 - ⚙️ **Configurable**: Timeout, headers, signal, debug options
 
 ## Authentication Options
diff --git a/packages/cozeloop-ai/README.zh-CN.md b/packages/cozeloop-ai/README.zh-CN.md
index 3ec4265..96dbac4 100644
--- a/packages/cozeloop-ai/README.zh-CN.md
+++ b/packages/cozeloop-ai/README.zh-CN.md
@@ -19,7 +19,7 @@ pnpm install @cozeloop/ai
 
 ### 2. 基础用法
 ```typescript
-import { ApiClient, PromptHub } from '@cozeloop/ai';
+import { ApiClient, PromptHub, PromptAsAService } from '@cozeloop/ai';
 
 // 1. 设置 ApiClient
 const apiClient = new ApiClient({
@@ -27,21 +27,35 @@ const apiClient = new ApiClient({
   token: 'your_access_token',
 });
 
-// 2. 使用 PromptHub 获取 Prompt
+// 2. 使用 `PromptHub` 或 `PromptAsAService`
 const promptHub = new PromptHub({
   // 或设置环境变量 process.env.COZELOOP_WORKSPACE_ID,
   workspaceId: 'your_workspace_id',
   apiClient,
 });
+// hub.getPrompt(key, version);
+// hub.formatPrompt(prompt);
 
-const prompt = await promptHub.getPrompt(
-  'your_prompt_key',
-  'prompt_version (optional)',
-);
+const model = new PromptAsAService({
+  // 或设置环境变量 process.env.COZELOOP_WORKSPACE_ID,
+  workspaceId: 'your_workspace_id',
+  // 要调用的 prompt
+  prompt: {
+    prompt_key: 'your_prompt_key',
+  },
+  apiClient,
+});
+// model.invoke({
+//   messages: [{ role: 'user', content: 'hi' }],
+// });
+// model.stream({
+//   messages: [{ role: 'user', content: 'hi' }],
+// });
 ```
 
 ## 主要特性
-- 🗄️ **Prompt Hub**: 在 [CozeLoop](https://loop.coze.cn) 平台开发、提交和发布 Prompt，使用 `PromptHub` 访问 Prompt。
+- 🗂️ **Prompt Hub**: 在 [CozeLoop](https://loop.coze.cn) 平台开发、提交和发布 Prompt，使用 `PromptHub` 访问 Prompt。
+- 🛠️ **Prompt as a Service**: 在 [CozeLoop](https://loop.coze.cn) 平台开发、提交和发布 Prompt，并作为服务调用。
 - 🔐 **多种鉴权方式**: PAT and JWT
 - ⚙️ **可配置**: 超时、请求头、信号、调试
 
diff --git a/packages/cozeloop-ai/__tests__/__mock__/base-http.ts b/packages/cozeloop-ai/__tests__/__mock__/base-http.ts
index a2097b6..18a1973 100644
--- a/packages/cozeloop-ai/__tests__/__mock__/base-http.ts
+++ b/packages/cozeloop-ai/__tests__/__mock__/base-http.ts
@@ -9,6 +9,12 @@ import { fileToStreamResp, headersToJson, setupMockServer } from './utils';
 
 export function setupBaseHttpMock() {
   const mockServer = setupServer(
+    http.post(/\/stream-event-error/i, () =>
+      fileToStreamResp(join(__dirname, 'base-stream-event-error.txt')),
+    ),
+    http.post(/\/stream-parse-error/i, () =>
+      fileToStreamResp(join(__dirname, 'base-stream-parse-error.txt')),
+    ),
     http.post(/\/stream/i, () =>
       fileToStreamResp(join(__dirname, 'base-stream.txt')),
     ),
diff --git a/packages/cozeloop-ai/__tests__/__mock__/base-stream-event-error.txt b/packages/cozeloop-ai/__tests__/__mock__/base-stream-event-error.txt
new file mode 100644
index 0000000..76936e7
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/__mock__/base-stream-event-error.txt
@@ -0,0 +1,5 @@
+data: {"seq": 1}
+
+event: error
+data: 500 Bad Gateway
+
diff --git a/packages/cozeloop-ai/__tests__/__mock__/base-stream-parse-error.txt b/packages/cozeloop-ai/__tests__/__mock__/base-stream-parse-error.txt
new file mode 100644
index 0000000..c49bac5
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/__mock__/base-stream-parse-error.txt
@@ -0,0 +1,2 @@
+data: {"seq"1: 1}
+
diff --git a/packages/cozeloop-ai/__tests__/__mock__/base-stream.txt b/packages/cozeloop-ai/__tests__/__mock__/base-stream.txt
index 1baed73..3a97a31 100644
--- a/packages/cozeloop-ai/__tests__/__mock__/base-stream.txt
+++ b/packages/cozeloop-ai/__tests__/__mock__/base-stream.txt
@@ -3,3 +3,4 @@ data: {"seq": 1}
 data: {"seq": 2}
 
 data: {"seq": 3}
+
diff --git a/packages/cozeloop-ai/__tests__/__mock__/ptaas-stream.txt b/packages/cozeloop-ai/__tests__/__mock__/ptaas-stream.txt
new file mode 100644
index 0000000..cb55a14
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/__mock__/ptaas-stream.txt
@@ -0,0 +1,84 @@
+data: {"message":{"role":"assistant","content":""},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"**"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"国"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"庆"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"长"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"假"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"**\\n\\n"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"山"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"川"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"河"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"海"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"舞"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"锦"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"绣"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"，"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"人"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"间"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"繁"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"华"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"庆"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"六"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"合"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"。"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"  \\n"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"载"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"歌"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"载"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"舞"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"庆"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"华"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"诞"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"，"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"共"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"庆"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"华"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"诞"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"风"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"景"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"好"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":"。"},"finish_reason":""}
+
+data: {"message":{"role":"assistant","content":""},"finish_reason":"stop"}
+
+data: {"message":{"role":"assistant","content":""},"finish_reason":"","usage":{"output_tokens":603,"input_tokens":468}}
+
diff --git a/packages/cozeloop-ai/__tests__/__mock__/ptaas.ts b/packages/cozeloop-ai/__tests__/__mock__/ptaas.ts
new file mode 100644
index 0000000..8cb6784
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/__mock__/ptaas.ts
@@ -0,0 +1,53 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+import { join } from 'node:path';
+
+import { setupServer } from 'msw/node';
+import { http, passthrough } from 'msw';
+
+import { type ExecutePromptReply } from '../../src';
+import { fileToStreamResp, setupMockServer, successResp } from './utils';
+
+const basicReply: ExecutePromptReply = {
+  message: {
+    role: 'assistant',
+    content:
+      '**国庆长假**\\n\\n金秋国庆迎盛世，游人欢笑赏风景。  \\n家国同庆情更浓，祝福祖国繁荣富强。',
+    reasoning_content: '',
+    tool_call_id: '',
+  },
+  finish_reason: 'stop',
+  usage: { input_tokens: 130, output_tokens: 60 },
+};
+
+export function setupPTaaSMock() {
+  const mockServer = setupServer(
+    http.all(/.*/, req => {
+      const pass = Boolean(req.request.headers.get('x-pass'));
+      return pass ? passthrough() : undefined;
+    }),
+    http.post(/\/v1\/loop\/prompts\/execute$/, req => {
+      const executeType = req.request.headers.get('x-mock');
+
+      switch (executeType) {
+        case 'basic-invoke':
+          return successResp(basicReply);
+        default:
+          return passthrough();
+      }
+    }),
+    http.post(/\/v1\/loop\/prompts\/execute_streaming/, req => {
+      const executeType = req.request.headers.get('x-mock');
+
+      switch (executeType) {
+        case 'basic-stream':
+          return fileToStreamResp(join(__dirname, 'ptaas-stream.txt'));
+        default:
+          return passthrough();
+      }
+    }),
+  );
+
+  return setupMockServer(mockServer);
+}
diff --git a/packages/cozeloop-ai/__tests__/__mock__/utils.ts b/packages/cozeloop-ai/__tests__/__mock__/utils.ts
index c4b753b..21d2e4c 100644
--- a/packages/cozeloop-ai/__tests__/__mock__/utils.ts
+++ b/packages/cozeloop-ai/__tests__/__mock__/utils.ts
@@ -13,14 +13,35 @@ export function headersToJson(headers: Headers) {
   return obj;
 }
 
+function randomSplitString(input?: string): string[] {
+  if (!input?.length) {
+    return [];
+  }
+
+  const result: string[] = [];
+  const size = Math.floor(Math.random() * input.length) + 1;
+  for (let i = 0; i < input.length; i += size) {
+    result.push(input.slice(i, i + size));
+  }
+
+  return result;
+}
+
 export async function fileToStreamResp(fileName: string) {
-  const lines = (await readFile(fileName, 'utf-8')).toString().split('\n');
+  const lines = (await readFile(fileName, 'utf-8')).toString().split('\n\n');
   const stream = new ReadableStream({
     start(controller) {
       const total = lines.length;
       for (let i = 0; i < total; i++) {
-        const suffix = i === total - 1 ? '' : '\n\n';
-        controller.enqueue(`${lines[i]}${suffix}`);
+        if (!lines[i]) {
+          continue;
+        }
+        const str = i === total - 1 ? lines[i] : `${lines[i]}\n\n`;
+        const pieces = randomSplitString(str);
+
+        for (const it of pieces) {
+          controller.enqueue(it);
+        }
       }
       controller.close();
     },
diff --git a/packages/cozeloop-ai/__tests__/api/api-client.test.ts b/packages/cozeloop-ai/__tests__/api/api-client.test.ts
index dfb6165..410592f 100644
--- a/packages/cozeloop-ai/__tests__/api/api-client.test.ts
+++ b/packages/cozeloop-ai/__tests__/api/api-client.test.ts
@@ -43,6 +43,34 @@ describe('Http Test', () => {
     }
   });
 
+  it('Basic POST streaming with parse error', async () => {
+    const resp = await apiClient.post<AsyncGenerator<{ seq: number }>>(
+      '/stream-parse-error',
+      undefined,
+      true,
+    );
+
+    await expect(async () => {
+      for await (const chunk of resp) {
+        console.info(chunk);
+      }
+    }).rejects.toThrowError(SyntaxError);
+  });
+
+  it('Basic POST streaming with event error', async () => {
+    const resp = await apiClient.post<AsyncGenerator<{ seq: number }>>(
+      '/stream-event-error',
+      undefined,
+      true,
+    );
+
+    await expect(async () => {
+      for await (const chunk of resp) {
+        console.info(chunk);
+      }
+    }).rejects.toThrowError(/500 Bad Gateway/);
+  });
+
   it('Basic PUT', async () => {
     const resp = await apiClient.put<BaseHttpResp>('/basic');
 
diff --git a/packages/cozeloop-ai/__tests__/auth/utils.test.ts b/packages/cozeloop-ai/__tests__/auth/utils.test.ts
new file mode 100644
index 0000000..780704a
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/auth/utils.test.ts
@@ -0,0 +1,30 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+import { delay, randomStr } from '../../src/auth/utils';
+
+describe('delay', () => {
+  it('should delay for the specified amount of time', async () => {
+    const start = Date.now();
+    const delayTime = 100; // Delay for 100 milliseconds
+
+    await delay(delayTime);
+
+    const end = Date.now();
+    const elapsed = end - start;
+
+    // Allow for a small margin of error (e.g., 5 milliseconds)
+    expect(elapsed).toBeGreaterThanOrEqual(delayTime - 5);
+    expect(elapsed).toBeLessThanOrEqual(delayTime + 5);
+  });
+});
+
+describe('randomStr', () => {
+  it('should generate a random string', () => {
+    const randomString1 = randomStr();
+    const randomString2 = randomStr();
+
+    expect(randomString1).toBeTruthy();
+    expect(randomString2).toBeTruthy();
+    expect(randomString1).not.toEqual(randomString2);
+  });
+});
diff --git a/packages/cozeloop-ai/__tests__/prompt/converter.test.ts b/packages/cozeloop-ai/__tests__/prompt/converter.test.ts
new file mode 100644
index 0000000..b9765f1
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/prompt/converter.test.ts
@@ -0,0 +1,327 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+import {
+  toLoopToolCalls,
+  toLoopPart,
+  toLoopMessage,
+  toLoopMessages,
+  toVariableVal,
+  toVariableVals,
+} from '../../src/prompt/converter';
+import {
+  type ToolCall,
+  type ContentPart,
+  type Message,
+  type PromptVariables,
+} from '../../src/prompt';
+
+describe('toLoopToolCalls', () => {
+  it('should return undefined when input is undefined', () => {
+    expect(toLoopToolCalls(undefined)).toBeUndefined();
+  });
+
+  it('should return an empty array when input is an empty array', () => {
+    expect(toLoopToolCalls([])).toEqual([]);
+  });
+
+  it('should convert ToolCall array to LoopToolCall array', () => {
+    const toolCalls: ToolCall[] = [
+      {
+        id: '1',
+        type: 'function',
+        function: { name: 'search', arguments: 'query=hello' },
+      },
+      {
+        id: '2',
+        type: 'function',
+        function: { name: 'analyze', arguments: 'text=world' },
+      },
+    ];
+
+    const expected = [
+      {
+        id: '1',
+        type: 'function',
+        function_call: { name: 'search', arguments: 'query=hello' },
+      },
+      {
+        id: '2',
+        type: 'function',
+        function_call: { name: 'analyze', arguments: 'text=world' },
+      },
+    ];
+
+    expect(toLoopToolCalls(toolCalls)).toEqual(expected);
+  });
+});
+
+describe('toLoopPart', () => {
+  it('should convert ContentPartText to LoopContentPart', () => {
+    const contentPart: ContentPart = { type: 'text', text: 'hello' };
+    const expected = { type: 'text', text: 'hello' };
+
+    expect(toLoopPart(contentPart)).toEqual(expected);
+  });
+
+  it('should convert ContentPartImage to LoopContentPart', () => {
+    const contentPart: ContentPart = {
+      type: 'image_url',
+      image_url: { url: 'https://example.com/image.jpg' },
+    };
+    const expected = {
+      type: 'image_url',
+      image_url: 'https://example.com/image.jpg',
+    };
+
+    expect(toLoopPart(contentPart)).toEqual(expected);
+  });
+
+  it('should throw an error for unsupported content type', () => {
+    const contentPart: any = { type: 'unknown', data: 'invalid' };
+    expect(() => toLoopPart(contentPart)).toThrowError(
+      '[toLoopPart] unknown unsupported',
+    );
+  });
+});
+
+describe('toLoopMessage', () => {
+  it('should convert system Message to LoopMessage', () => {
+    const message: Message = { role: 'system', content: 'system message' };
+    const expected = { role: 'system', content: 'system message' };
+
+    expect(toLoopMessage(message)).toEqual(expected);
+  });
+
+  it('should convert user Message to LoopMessage', () => {
+    const message: Message = {
+      role: 'user',
+      content: 'user message',
+      parts: [{ type: 'text', text: 'hello' }],
+    };
+    const expected = {
+      role: 'user',
+      content: 'user message',
+      parts: [{ type: 'text', text: 'hello' }],
+    };
+
+    expect(toLoopMessage(message)).toEqual(expected);
+  });
+
+  it('should convert tool Message to LoopMessage', () => {
+    const message: Message = {
+      role: 'tool',
+      content: 'tool message',
+      tool_call_id: '1',
+    };
+    const expected = {
+      role: 'tool',
+      content: 'tool message',
+      tool_call_id: '1',
+    };
+
+    expect(toLoopMessage(message)).toEqual(expected);
+  });
+
+  it('should convert assistant Message to LoopMessage', () => {
+    const message: Message = {
+      role: 'assistant',
+      content: 'assistant message',
+      parts: [
+        {
+          type: 'image_url',
+          image_url: { url: 'https://example.com/image.jpg' },
+        },
+      ],
+      tool_calls: [
+        {
+          id: '1',
+          type: 'function',
+          function: { name: 'search', arguments: 'query=hello' },
+        },
+      ],
+    };
+    const expected = {
+      role: 'assistant',
+      content: 'assistant message',
+      parts: [
+        { type: 'image_url', image_url: 'https://example.com/image.jpg' },
+      ],
+      tool_calls: [
+        {
+          id: '1',
+          type: 'function',
+          function_call: { name: 'search', arguments: 'query=hello' },
+        },
+      ],
+    };
+
+    expect(toLoopMessage(message)).toEqual(expected);
+  });
+
+  it('should throw an error for unsupported role', () => {
+    const message: any = { role: 'unknown', content: 'invalid message' };
+    expect(() => toLoopMessage(message)).toThrowError(
+      '[toLoopMessage] unknown unsupported',
+    );
+  });
+});
+
+describe('toLoopMessages', () => {
+  it('should return an empty array when input is undefined or empty', () => {
+    expect(toLoopMessages(undefined)).toEqual([]);
+    expect(toLoopMessages([])).toEqual([]);
+  });
+
+  it('should convert Message array to LoopMessage array', () => {
+    const messages: Message[] = [
+      { role: 'system', content: 'system message' },
+      {
+        role: 'user',
+        content: 'user message',
+        parts: [{ type: 'text', text: 'hello' }],
+      },
+      { role: 'tool', content: 'tool message', tool_call_id: '1' },
+    ];
+    const expected = [
+      { role: 'system', content: 'system message' },
+      {
+        role: 'user',
+        content: 'user message',
+        parts: [{ type: 'text', text: 'hello' }],
+      },
+      { role: 'tool', content: 'tool message', tool_call_id: '1' },
+    ];
+
+    expect(toLoopMessages(messages)).toEqual(expected);
+  });
+});
+
+describe('toVariableVal', () => {
+  it('should convert primitive value to VariableVal', () => {
+    const key = 'stringValue';
+    const value = 'hello';
+    const expected = { key, value };
+
+    expect(toVariableVal(key, value)).toEqual(expected);
+  });
+
+  it('should convert null to undefined', () => {
+    const key = 'nullValue';
+    const value = null;
+
+    expect(toVariableVal(key, value)).toBeUndefined();
+  });
+
+  it('should convert Message to VariableVal', () => {
+    const key = 'messageValue';
+    const value: Message = { role: 'user', content: 'user message' };
+    const expected = {
+      key,
+      placeholder_messages: [{ role: 'user', content: 'user message' }],
+    };
+
+    expect(toVariableVal(key, value)).toEqual(expected);
+  });
+
+  it('should convert Message array to VariableVal', () => {
+    const key = 'messageArrayValue';
+    const value: Message[] = [
+      { role: 'system', content: 'system message' },
+      { role: 'user', content: 'user message' },
+    ];
+    const expected = {
+      key,
+      placeholder_messages: [
+        { role: 'system', content: 'system message' },
+        { role: 'user', content: 'user message' },
+      ],
+    };
+
+    expect(toVariableVal(key, value)).toEqual(expected);
+  });
+
+  it('should convert ContentPart array to VariableVal', () => {
+    const key = 'contentPartArrayValue';
+    const value: ContentPart[] = [
+      { type: 'text', text: 'hello' },
+      {
+        type: 'image_url',
+        image_url: { url: 'https://example.com/image.jpg' },
+      },
+    ];
+    const expected = {
+      key,
+      multi_part_values: [
+        { type: 'text', text: 'hello' },
+        { type: 'image_url', image_url: 'https://example.com/image.jpg' },
+      ],
+    };
+
+    expect(toVariableVal(key, value)).toEqual(expected);
+  });
+
+  it('should return undefined for unsupported value types', () => {
+    const key = 'functionValue';
+    const value = () => {
+      /** no-op */
+    };
+
+    expect(toVariableVal(key, value)).toBeUndefined();
+  });
+});
+
+describe('toVariableVals', () => {
+  it('should return undefined when input is undefined', () => {
+    expect(toVariableVals(undefined)).toBeUndefined();
+  });
+
+  it('should convert PromptVariables to VariableVal array', () => {
+    const variables: PromptVariables = {
+      stringValue: 'hello',
+      numberValue: 42,
+      booleanValue: true,
+      messageValue: { role: 'user', content: 'user message' },
+      messageArrayValue: [
+        { role: 'system', content: 'system message' },
+        { role: 'user', content: 'user message' },
+      ],
+      contentPartArrayValue: [
+        { type: 'text', text: 'hello' },
+        {
+          type: 'image_url',
+          image_url: { url: 'https://example.com/image.jpg' },
+        },
+      ],
+      nullValue: null,
+      undefinedValue: undefined,
+      functionValue: () => {
+        /** no-op */
+      },
+    };
+    const expected = [
+      { key: 'stringValue', value: 'hello' },
+      { key: 'numberValue', value: '42' },
+      { key: 'booleanValue', value: 'true' },
+      {
+        key: 'messageValue',
+        placeholder_messages: [{ role: 'user', content: 'user message' }],
+      },
+      {
+        key: 'messageArrayValue',
+        placeholder_messages: [
+          { role: 'system', content: 'system message' },
+          { role: 'user', content: 'user message' },
+        ],
+      },
+      {
+        key: 'contentPartArrayValue',
+        multi_part_values: [
+          { type: 'text', text: 'hello' },
+          { type: 'image_url', image_url: 'https://example.com/image.jpg' },
+        ],
+      },
+    ];
+    expect(toVariableVals(variables)).toEqual(expected);
+  });
+});
diff --git a/packages/cozeloop-ai/__tests__/prompt/guard.test.ts b/packages/cozeloop-ai/__tests__/prompt/guard.test.ts
new file mode 100644
index 0000000..24c256e
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/prompt/guard.test.ts
@@ -0,0 +1,108 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+import {
+  isContentPart,
+  isContentPartArr,
+  isMessage,
+  isMessageArr,
+} from '../../src/prompt/guard';
+
+describe('isMessage', () => {
+  it('should return true for valid message objects', () => {
+    const validMessage = { role: 'user', content: 'Hello' };
+    expect(isMessage(validMessage)).toBe(true);
+  });
+
+  it('should return false for non-object values', () => {
+    expect(isMessage(null)).toBe(false);
+    expect(isMessage(undefined)).toBe(false);
+    expect(isMessage(123)).toBe(false);
+    expect(isMessage('hello')).toBe(false);
+  });
+
+  it('should return false for objects with invalid role', () => {
+    const invalidMessage = { role: 'invalid', content: 'Hello' };
+    expect(isMessage(invalidMessage)).toBe(false);
+  });
+});
+
+describe('isMessageArr', () => {
+  it('should return true for an array of valid message objects', () => {
+    const validMessages = [
+      { role: 'user', content: 'Hello' },
+      { role: 'assistant', content: 'Hi there!' },
+    ];
+    expect(isMessageArr(validMessages)).toBe(true);
+  });
+
+  it('should return false for non-array values', () => {
+    expect(isMessageArr(null)).toBe(false);
+    expect(isMessageArr(undefined)).toBe(false);
+    expect(isMessageArr(123)).toBe(false);
+    expect(isMessageArr('hello')).toBe(false);
+  });
+
+  it('should return false for an array containing invalid message objects', () => {
+    const invalidMessages = [
+      { role: 'user', content: 'Hello' },
+      { role: 'invalid', content: 'Hi there!' },
+    ];
+    expect(isMessageArr(invalidMessages)).toBe(false);
+  });
+});
+
+describe('isContentPart', () => {
+  it('should return true for valid text content parts', () => {
+    const validTextPart = { type: 'text', text: 'Hello' };
+    expect(isContentPart(validTextPart)).toBe(true);
+  });
+
+  it('should return true for valid image content parts', () => {
+    const validImagePart = {
+      type: 'image_url',
+      image_url: { url: 'https://example.com/image.jpg' },
+    };
+    expect(isContentPart(validImagePart)).toBe(true);
+  });
+
+  it('should return false for non-object values', () => {
+    expect(isContentPart(null)).toBe(false);
+    expect(isContentPart(undefined)).toBe(false);
+    expect(isContentPart(123)).toBe(false);
+    expect(isContentPart('hello')).toBe(false);
+  });
+
+  it('should return false for objects without a valid type', () => {
+    const invalidPart = { type: 'invalid', text: 'Hello' };
+    expect(isContentPart(invalidPart)).toBe(false);
+  });
+});
+
+describe('isContentPartArr', () => {
+  it('should return true for an array of valid content parts', () => {
+    const validParts = [
+      { type: 'text', text: 'Hello' },
+      {
+        type: 'image_url',
+        image_url: { url: 'https://example.com/image.jpg' },
+      },
+    ];
+    expect(isContentPartArr(validParts)).toBe(true);
+  });
+
+  it('should return false for non-array values', () => {
+    expect(isContentPartArr(null)).toBe(false);
+    expect(isContentPartArr(undefined)).toBe(false);
+    expect(isContentPartArr(123)).toBe(false);
+    expect(isContentPartArr('hello')).toBe(false);
+  });
+
+  it('should return false for an array containing invalid content parts', () => {
+    const invalidParts = [
+      { type: 'text', text: 'Hello' },
+      { type: 'invalid', text: 'Hi there!' },
+    ];
+    expect(isContentPartArr(invalidParts)).toBe(false);
+  });
+});
diff --git a/packages/cozeloop-ai/__tests__/prompt/hub.test.ts b/packages/cozeloop-ai/__tests__/prompt/hub.test.ts
index 37a0447..ebf2459 100644
--- a/packages/cozeloop-ai/__tests__/prompt/hub.test.ts
+++ b/packages/cozeloop-ai/__tests__/prompt/hub.test.ts
@@ -9,7 +9,7 @@ import { simpleConsoleLogger } from '../../src/utils/logger';
 import { cozeLoopTracer } from '../../src/tracer';
 import { PromptCache } from '../../src/prompt/cache';
 import { PromptHub, type PromptVariables } from '../../src/prompt';
-import { PromptApi, type TemplateMessage } from '../../src/api';
+import { PromptApi, type LoopMessage } from '../../src/api';
 
 config();
 
@@ -47,6 +47,7 @@ describe('Test Prompt Hub', () => {
 
     expect(prompt?.prompt_key).toBe(key);
     expect(prompt?.version).toBe(version);
+    expect(hub.cache).toBeInstanceOf(PromptCache);
 
     // 1) format prompt without variables
     (() => {
@@ -61,7 +62,7 @@ describe('Test Prompt Hub', () => {
     // var1: str
     // placeholder: messages
     (() => {
-      const placeholderMessages: TemplateMessage[] = [
+      const placeholderMessages: LoopMessage[] = [
         { role: 'assistant', content: 'fake_content' },
         { role: 'user', content: 'fake_content' },
       ];
@@ -90,7 +91,7 @@ describe('Test Prompt Hub', () => {
       };
       const messages = hub.formatPrompt(prompt, variables);
 
-      expect(messages[0].content.includes('{{var1}}')).toBe(false);
+      expect(messages[0].content?.includes('{{var1}}')).toBe(false);
       expect(messages[1].content).contains(variables.var2);
     })();
   });
@@ -125,7 +126,7 @@ describe('Test Prompt Hub', () => {
       apiClient: {
         headers: { 'x-template-type': 'jinja2' }, // for mock
       },
-      traceable: false,
+      traceable: true,
     });
 
     const key = 'loop12';
diff --git a/packages/cozeloop-ai/__tests__/prompt/ptaas.test.ts b/packages/cozeloop-ai/__tests__/prompt/ptaas.test.ts
new file mode 100644
index 0000000..888748b
--- /dev/null
+++ b/packages/cozeloop-ai/__tests__/prompt/ptaas.test.ts
@@ -0,0 +1,53 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+import { setupPTaaSMock } from '../__mock__/ptaas';
+import { PromptAsAService } from '../../src';
+
+describe('Test Prompt As a Service', () => {
+  const httpMock = setupPTaaSMock();
+  beforeAll(async () => {
+    await httpMock.start();
+  });
+  afterAll(async () => {
+    await httpMock.close();
+  });
+  afterEach(() => httpMock.reset());
+
+  it('#1 basic invoke', async () => {
+    const model = new PromptAsAService({
+      prompt: {
+        prompt_key: 'CozeLoop_Travel_Master',
+      },
+      apiClient: {
+        headers: { 'x-mock': 'basic-invoke' },
+      },
+    });
+
+    const reply = await model.invoke({
+      messages: [{ role: 'user', content: '做一首诗' }],
+    });
+
+    expect(reply?.finish_reason).toBe('stop');
+    expect(reply?.message.role).toBe('assistant');
+  });
+
+  it('#2 basic stream', async () => {
+    const model = new PromptAsAService({
+      prompt: {
+        prompt_key: 'CozeLoop_Travel_Master1',
+      },
+      apiClient: {
+        headers: { 'x-mock': 'basic-stream' },
+      },
+    });
+
+    const replyStream = await model.stream({
+      messages: [{ role: 'user', content: '做一首诗' }],
+    });
+
+    for await (const chunk of replyStream) {
+      expect(chunk.message).toBeTruthy();
+    }
+  });
+});
diff --git a/packages/cozeloop-ai/__tests__/prompt/trace.test.ts b/packages/cozeloop-ai/__tests__/prompt/trace.test.ts
index e478622..b68bbf2 100644
--- a/packages/cozeloop-ai/__tests__/prompt/trace.test.ts
+++ b/packages/cozeloop-ai/__tests__/prompt/trace.test.ts
@@ -7,7 +7,7 @@ import {
   toPromptTemplateInput,
   toPromptTemplateOutput,
 } from '../../src/prompt/trace';
-import type { TemplateMessage } from '../../src/api';
+import type { LoopMessage } from '../../src/api';
 
 // Mock serializeTagValue to verify calls
 vi.mock('../../src/tracer/utils', () => ({
@@ -54,7 +54,7 @@ describe('🧪 Prompt Trace Functions', () => {
 
   describe('toPromptTemplateInput', () => {
     it('should serialize template input with messages and variable map', () => {
-      const messages: TemplateMessage[] = [
+      const messages: LoopMessage[] = [
         {
           role: 'system',
           content: 'You are a helpful assistant',
@@ -88,7 +88,7 @@ describe('🧪 Prompt Trace Functions', () => {
     });
 
     it('should handle empty messages and variable map', () => {
-      const messages: TemplateMessage[] = [];
+      const messages: LoopMessage[] = [];
       const variableMap: PromptVariables = {};
 
       const result = toPromptTemplateInput(messages, variableMap);
@@ -101,7 +101,7 @@ describe('🧪 Prompt Trace Functions', () => {
     });
 
     it('should handle only messages without variable map', () => {
-      const messages: TemplateMessage[] = [
+      const messages: LoopMessage[] = [
         {
           role: 'user',
           content: 'Hello',
diff --git a/packages/cozeloop-ai/package.json b/packages/cozeloop-ai/package.json
index 4a1e94e..785efde 100644
--- a/packages/cozeloop-ai/package.json
+++ b/packages/cozeloop-ai/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cozeloop/ai",
-  "version": "0.0.8",
+  "version": "0.0.9",
   "description": "Official Node.js SDK of CozeLoop | 扣子罗盘官方 Node.js SDK",
   "keywords": [
     "cozeloop",
diff --git a/packages/cozeloop-ai/src/api/api-client/utils.ts b/packages/cozeloop-ai/src/api/api-client/utils.ts
index 5e3c7c9..30abc0a 100644
--- a/packages/cozeloop-ai/src/api/api-client/utils.ts
+++ b/packages/cozeloop-ai/src/api/api-client/utils.ts
@@ -83,8 +83,8 @@ export function parseEventChunk<T>(chunk: string) {
     }
   }
 
-  if (event === 'gateway-error') {
-    throw new Error(data || 'gateway-error');
+  if (event.includes('error')) {
+    throw new Error(data || 'SSE event error');
   }
 
   return JSON.parse(data) as T;
diff --git a/packages/cozeloop-ai/src/api/prompt/index.ts b/packages/cozeloop-ai/src/api/prompt/index.ts
index 67b7df9..9d17c42 100644
--- a/packages/cozeloop-ai/src/api/prompt/index.ts
+++ b/packages/cozeloop-ai/src/api/prompt/index.ts
@@ -1,9 +1,17 @@
 // Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 // SPDX-License-Identifier: MIT
+import { type PullPromptReq, type PullPromptResp } from './types/prompt';
+import {
+  type ExecutePromptResp,
+  type ExecutePromptReq,
+  type StreamingExecutePromptResp,
+} from './types/execute';
 import { BaseApi } from '../base';
-import type { PullPromptReq, PullPromptResp } from './types';
+import { type RequestOptions } from '../api-client';
 
-export type * from './types';
+export type * from './types/common';
+export type * from './types/execute';
+export type * from './types/prompt';
 
 export class PromptApi extends BaseApi {
   pullPrompt(req: PullPromptReq) {
@@ -11,4 +19,21 @@ export class PromptApi extends BaseApi {
 
     return this._client.post<PullPromptResp>(url, req);
   }
+
+  executePrompt(req: ExecutePromptReq, options?: RequestOptions) {
+    const url = '/v1/loop/prompts/execute';
+
+    return this._client.post<ExecutePromptResp>(url, req, false, options);
+  }
+
+  streamingExecutePrompt(req: ExecutePromptReq, options?: RequestOptions) {
+    const url = '/v1/loop/prompts/execute_streaming';
+
+    return this._client.post<StreamingExecutePromptResp>(
+      url,
+      req,
+      true,
+      options,
+    );
+  }
 }
diff --git a/packages/cozeloop-ai/src/api/prompt/types/common.ts b/packages/cozeloop-ai/src/api/prompt/types/common.ts
new file mode 100644
index 0000000..8a1644c
--- /dev/null
+++ b/packages/cozeloop-ai/src/api/prompt/types/common.ts
@@ -0,0 +1,86 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+export type LoopContentType =
+  | 'text'
+  | 'image_url'
+  | 'base64_data'
+  | 'multi_part_variable';
+
+export interface LoopContentPart {
+  type: LoopContentType;
+  text?: string;
+  image_url?: string;
+  base64_data?: string;
+}
+
+export type LoopRole = 'system' | 'user' | 'tool' | 'assistant' | 'placeholder';
+
+export interface LoopMessage {
+  /** 角色 */
+  role: LoopRole;
+  /** 消息内容 */
+  content?: string;
+  /** 多模态内容 */
+  parts?: LoopContentPart[];
+  /** 推理思考内容 */
+  reasoning_content?: string;
+  /** tool调用ID（role为tool时有效） */
+  tool_call_id?: string;
+  /** tool调用（role为assistant时有效） */
+  tool_calls?: LoopToolCall[];
+}
+
+export interface LoopTool {
+  type: 'function';
+  function: {
+    name: string;
+    description: string;
+    parameters: string;
+  };
+}
+
+export interface LoopToolCall {
+  index?: number;
+  id?: string;
+  type?: 'function';
+  function_call?: {
+    name?: string;
+    arguments?: string;
+  };
+}
+
+export interface LoopToolCallConfig {
+  tool_choice?: 'auto' | 'none';
+}
+
+export type VariableType =
+  | 'string'
+  | 'boolean'
+  | 'integer'
+  | 'float'
+  | 'object'
+  | 'array<string>'
+  | 'array<boolean>'
+  | 'array<integer>'
+  | 'array<float>'
+  | 'array<object>'
+  | 'placeholder'
+  | 'multi_part';
+
+export interface VariableDef {
+  key: string;
+  type: VariableType;
+  desc?: string;
+}
+
+export interface VariableVal {
+  /** 变量key */
+  key?: string;
+  /** 普通变量值（非string类型，如boolean、integer、float、object等，序列化后传入）*/
+  value?: string;
+  /** placeholder变量值 */
+  placeholder_messages?: LoopMessage[];
+  /** 多模态变量值 */
+  multi_part_values?: LoopContentPart[];
+}
diff --git a/packages/cozeloop-ai/src/api/prompt/types/execute.ts b/packages/cozeloop-ai/src/api/prompt/types/execute.ts
new file mode 100644
index 0000000..4fb0e94
--- /dev/null
+++ b/packages/cozeloop-ai/src/api/prompt/types/execute.ts
@@ -0,0 +1,32 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+
+import { type BaseApiResp } from '../../base';
+import { type PromptQuery } from './prompt';
+import { type VariableVal, type LoopMessage } from './common';
+
+export interface ExecutePromptReq {
+  /** 工作空间ID */
+  workspace_id?: string;
+  /** Prompt 标识 */
+  prompt_identifier?: PromptQuery;
+  /** 变量值 */
+  variable_vals?: VariableVal[];
+  /** 消息 */
+  messages?: LoopMessage[];
+}
+
+export interface TokenUsage {
+  input_tokens?: number;
+  output_tokens?: number;
+}
+
+export interface ExecutePromptReply {
+  message: LoopMessage;
+  finish_reason: string;
+  usage: TokenUsage;
+}
+
+export type ExecutePromptResp = BaseApiResp<ExecutePromptReply>;
+
+export type StreamingExecutePromptResp = AsyncGenerator<ExecutePromptReply>;
diff --git a/packages/cozeloop-ai/src/api/prompt/types.ts b/packages/cozeloop-ai/src/api/prompt/types/prompt.ts
similarity index 52%
rename from packages/cozeloop-ai/src/api/prompt/types.ts
rename to packages/cozeloop-ai/src/api/prompt/types/prompt.ts
index 333f291..997f7c4 100644
--- a/packages/cozeloop-ai/src/api/prompt/types.ts
+++ b/packages/cozeloop-ai/src/api/prompt/types/prompt.ts
@@ -1,45 +1,34 @@
 // Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 // SPDX-License-Identifier: MIT
-import type { BaseApiResp } from '../base';
 
-export interface TemplateContentPart {
-  /** variable type */
-  type: 'text' | 'multi_part_variable';
-  /** variable name */
-  text: string;
-}
+import { type BaseApiResp } from '../../base';
+import {
+  type LoopMessage,
+  type LoopTool,
+  type LoopToolCallConfig,
+  type VariableDef,
+} from './common';
 
-export interface TemplateMessage {
-  role: 'system' | 'user' | 'assistant' | 'placeholder';
-  content: string;
-  parts?: TemplateContentPart[];
+export interface PromptQuery {
+  /** prompt_key */
+  prompt_key?: string;
+  /** prompt版本 */
+  version?: string;
+  /** prompt版本标识（如果version不为空，该字段会被忽略） */
+  label?: string;
 }
 
-export interface VariableDef {
-  key: string;
-  type: 'string' | 'placeholder' | 'multi_part';
-  desc?: string;
+export interface PullPromptReq {
+  workspace_id: string;
+  queries: PromptQuery[];
 }
 
 export interface PromptTemplate {
   template_type: 'normal' | 'jinja2';
-  messages: TemplateMessage[];
+  messages: LoopMessage[];
   variable_defs: VariableDef[];
 }
 
-export interface Tool {
-  type: 'function';
-  function: {
-    name: string;
-    description: string;
-    parameters: string;
-  };
-}
-
-export interface ToolCallConfig {
-  tool_choice?: 'auto' | 'none';
-}
-
 export interface LLMConfig {
   temperature?: number;
   max_tokens?: number;
@@ -55,23 +44,11 @@ export interface Prompt {
   prompt_key: string;
   version: string;
   prompt_template: PromptTemplate;
-  tools: Tool[];
-  tool_call_config?: ToolCallConfig;
+  tools: LoopTool[];
+  tool_call_config?: LoopToolCallConfig;
   llm_config: LLMConfig;
 }
 
-export interface PromptQuery {
-  prompt_key: string;
-  version?: string;
-  /** priority: version > label */
-  label?: string;
-}
-
-export interface PullPromptReq {
-  workspace_id: string;
-  queries: PromptQuery[];
-}
-
 export interface PromptResultItem {
   query: PromptQuery;
   prompt: Prompt;
diff --git a/packages/cozeloop-ai/src/global.d.ts b/packages/cozeloop-ai/src/global.d.ts
index 4666dab..aeb036f 100644
--- a/packages/cozeloop-ai/src/global.d.ts
+++ b/packages/cozeloop-ai/src/global.d.ts
@@ -34,6 +34,7 @@ declare module 'process' {
         /** SDK Version, which is injected via vitest or tsup from package.json */
         COZELOOP_VERSION: string;
         COZELOOP_API_TOKEN?: string;
+        COZELOOP_WORKSPACE_ID?: string;
       }
     }
   }
diff --git a/packages/cozeloop-ai/src/index.ts b/packages/cozeloop-ai/src/index.ts
index 28ebc4e..103c1e6 100644
--- a/packages/cozeloop-ai/src/index.ts
+++ b/packages/cozeloop-ai/src/index.ts
@@ -9,7 +9,7 @@ export { OAuthJWTFlow } from './auth';
 export type * from './auth';
 
 // prompt
-export { PromptHub } from './prompt';
+export { PromptHub, PromptAsAService } from './prompt';
 export type * from './prompt';
 
 // tracer
diff --git a/packages/cozeloop-ai/src/prompt/converter.ts b/packages/cozeloop-ai/src/prompt/converter.ts
new file mode 100644
index 0000000..c2ff380
--- /dev/null
+++ b/packages/cozeloop-ai/src/prompt/converter.ts
@@ -0,0 +1,138 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+import { stringifyVal } from '../utils/common';
+import {
+  type LoopToolCall,
+  type LoopMessage,
+  type LoopContentPart,
+  type VariableVal,
+} from '../api';
+import {
+  type ToolCall,
+  type Message,
+  type PromptVariables,
+  type ContentPart,
+} from './types';
+import { isContentPartArr, isMessage, isMessageArr } from './guard';
+
+export function toLoopToolCalls(toolCalls?: ToolCall[]) {
+  if (typeof toolCalls === 'undefined') {
+    return undefined;
+  }
+
+  if (!toolCalls.length) {
+    return [];
+  }
+
+  return toolCalls.map<LoopToolCall>(it => ({
+    id: it.id,
+    type: 'function',
+    function_call: {
+      name: it.function.name,
+      arguments: it.function.arguments,
+    },
+  }));
+}
+
+export function toLoopPart(part: ContentPart): LoopContentPart {
+  const { type } = part;
+  switch (type) {
+    case 'text':
+      return { type: 'text', text: part.text };
+    case 'image_url':
+      return { type: 'image_url', image_url: part.image_url.url };
+    default:
+      throw new Error(`[toLoopPart] ${type} unsupported`);
+  }
+}
+
+export function toLoopMessage(message: Message): LoopMessage {
+  switch (message.role) {
+    case 'system':
+      return {
+        role: 'system',
+        content: message.content,
+      };
+    case 'user':
+      return {
+        role: 'user',
+        content: message.content,
+        parts: message.parts?.map(it => toLoopPart(it)),
+      };
+    case 'tool':
+      return {
+        role: 'tool',
+        content: message.content,
+        tool_call_id: message.tool_call_id,
+      };
+    case 'assistant':
+      return {
+        role: 'assistant',
+        content: message.content,
+        parts: message.parts?.map(it => toLoopPart(it)),
+        tool_calls: toLoopToolCalls(message.tool_calls),
+      };
+    default:
+      throw new Error(`[toLoopMessage] ${message.role} unsupported`);
+  }
+}
+
+export function toLoopMessages(messages?: Message[]) {
+  if (!messages?.length) {
+    return [];
+  }
+
+  return messages.map(it => toLoopMessage(it));
+}
+
+export function toVariableVal(
+  key: string,
+  val: PromptVariables[keyof PromptVariables],
+): VariableVal | undefined {
+  switch (typeof val) {
+    case 'string':
+    case 'symbol':
+    case 'bigint':
+    case 'number':
+    case 'boolean':
+      return { key, value: stringifyVal(val) };
+    case 'object': {
+      if (val === null) {
+        return undefined;
+      }
+
+      if (isMessage(val)) {
+        return { key, placeholder_messages: [toLoopMessage(val)] };
+      }
+
+      if (isMessageArr(val)) {
+        return { key, placeholder_messages: toLoopMessages(val) };
+      }
+
+      if (isContentPartArr(val)) {
+        return { key, multi_part_values: val.map(it => toLoopPart(it)) };
+      }
+
+      return { key, value: stringifyVal(val) };
+    }
+    case 'undefined':
+    case 'function':
+    default:
+      return undefined;
+  }
+}
+
+export function toVariableVals(variables?: PromptVariables) {
+  if (typeof variables === 'undefined') {
+    return undefined;
+  }
+
+  const vals: VariableVal[] = [];
+
+  for (const [key, val] of Object.entries(variables)) {
+    const vv = toVariableVal(key, val);
+    vv && vals.push(vv);
+  }
+
+  return vals;
+}
diff --git a/packages/cozeloop-ai/src/prompt/guard.ts b/packages/cozeloop-ai/src/prompt/guard.ts
new file mode 100644
index 0000000..00bc502
--- /dev/null
+++ b/packages/cozeloop-ai/src/prompt/guard.ts
@@ -0,0 +1,48 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+import { type ContentPart, type Message } from './types';
+
+export function isMessage(val: unknown): val is Message {
+  if (typeof val !== 'object' || !val) {
+    return false;
+  }
+
+  const roleSet = new Set(['system', 'user', 'tool', 'assistant']);
+
+  return 'role' in val && typeof val.role === 'string' && roleSet.has(val.role);
+}
+
+export function isMessageArr(val: unknown): val is Message[] {
+  return Array.isArray(val) && val.every(it => isMessage(it));
+}
+
+export function isContentPart(val: unknown): val is ContentPart {
+  if (
+    typeof val !== 'object' ||
+    !val ||
+    !('type' in val) ||
+    typeof val.type !== 'string'
+  ) {
+    return false;
+  }
+
+  if (val.type === 'text') {
+    return 'text' in val && typeof val.text === 'string';
+  }
+
+  if (val.type === 'image_url') {
+    return Boolean(
+      'image_url' in val &&
+        typeof val.image_url === 'object' &&
+        val.image_url &&
+        'url' in val.image_url &&
+        typeof val.image_url.url === 'string',
+    );
+  }
+
+  return false;
+}
+
+export function isContentPartArr(val: unknown): val is ContentPart[] {
+  return Array.isArray(val) && val.every(it => isContentPart(it));
+}
diff --git a/packages/cozeloop-ai/src/prompt/hub.ts b/packages/cozeloop-ai/src/prompt/hub.ts
index 2c7b749..331613e 100644
--- a/packages/cozeloop-ai/src/prompt/hub.ts
+++ b/packages/cozeloop-ai/src/prompt/hub.ts
@@ -20,8 +20,8 @@ import {
 
 export class PromptHub {
   private _options: PromptHubOptions;
-  private readonly _cache: PromptCache;
   private _api: PromptApi;
+  private readonly _cache: PromptCache;
 
   /** Prompt cache instance */
   get cache() {
@@ -37,9 +37,7 @@ export class PromptHub {
     });
 
     this._options = mergeConfig<PromptHubOptions>(options, { workspaceId });
-
     this._api = new PromptApi(this._options.apiClient);
-
     this._cache = new PromptCache(options.cacheOptions || {}, this._api);
     this._cache.startPollingUpdate(workspaceId);
   }
diff --git a/packages/cozeloop-ai/src/prompt/index.ts b/packages/cozeloop-ai/src/prompt/index.ts
index 68b960b..b8366a6 100644
--- a/packages/cozeloop-ai/src/prompt/index.ts
+++ b/packages/cozeloop-ai/src/prompt/index.ts
@@ -1,12 +1,17 @@
 // Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 // SPDX-License-Identifier: MIT
 export { PromptHub } from './hub';
+export { PromptAsAService } from './ptaas';
 export type {
   PromptHubOptions,
   PromptCacheOptions,
   PromptVariables,
+  PromptVariableMap,
+  PromptExecuteOptions,
+  PromptAsAServiceOptions,
   Message,
   ContentPart,
   ContentPartImage,
   ContentPartText,
+  ToolCall,
 } from './types';
diff --git a/packages/cozeloop-ai/src/prompt/ptaas.ts b/packages/cozeloop-ai/src/prompt/ptaas.ts
new file mode 100644
index 0000000..36a4ea3
--- /dev/null
+++ b/packages/cozeloop-ai/src/prompt/ptaas.ts
@@ -0,0 +1,123 @@
+// Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+// SPDX-License-Identifier: MIT
+import { ensureProperty, EnvKeys } from '../utils/env';
+import { mergeConfig } from '../utils/common';
+import { type ExecutePromptReq, PromptApi } from '../api';
+import {
+  type PromptExecuteOptions,
+  type PromptAsAServiceOptions,
+} from './types';
+import { toVariableVals, toLoopMessages } from './converter';
+
+export class PromptAsAService {
+  private _options: PromptAsAServiceOptions;
+  private _api: PromptApi;
+
+  constructor(options: PromptAsAServiceOptions) {
+    const workspaceId = ensureProperty({
+      propName: 'workspaceId',
+      envKey: EnvKeys.WORKSPACE_ID,
+      value: options.workspaceId,
+      tag: 'PromptService',
+    });
+    this._options = mergeConfig<PromptAsAServiceOptions>(options, {
+      workspaceId,
+    });
+    this._api = new PromptApi(this._options.apiClient);
+  }
+
+  private _getExecuteReq(options: PromptExecuteOptions) {
+    // const { messages, variables, prompt } = options;
+    const prompt = options.prompt ?? this._options.prompt;
+    if (typeof prompt === 'undefined') {
+      throw new Error('[PromptAsAService] Prompt is unprovided');
+    }
+
+    const req: ExecutePromptReq = {
+      workspace_id: this._options.workspaceId,
+      prompt_identifier: prompt,
+      variable_vals: toVariableVals(options.variables),
+      messages: toLoopMessages(options.messages),
+    };
+
+    return req;
+  }
+
+  /**
+   * Invoke prompt-as-a-service
+   *
+   * @param options {@link PromptExecuteOptions}
+   *
+   * @example
+   * ```typescript
+   *
+   * // 1. invoke with messages
+   * const model = new PromptAsAService({
+   *   workspaceId: 'your_workspace_id',
+   *   prompt: {
+   *     prompt_key: 'your_prompt_key',
+   *     // version: '0.0.1',
+   *   },
+   *   apiClient: {
+   *     token: 'pat_xxx',
+   *   },
+   * });
+   *
+   * const reply = await model.invoke({
+   *   messages: [
+   *     { role: 'user', content: 'hi' },
+   *   ],
+   * });
+   *
+   * // 2. invoke, and specify prompt at runtime
+   * const model = new PromptAsAService({});
+   *
+   * const reply = await model.invoke({
+   *   // higher priority than PromptAsAService constructor params
+   *   prompt: {
+   *     prompt_key: 'your_prompt_key',
+   *     // version: '0.0.1',
+   *   },
+   *   messages: [
+   *     { role: 'user', content: 'hi' },
+   *   ],
+   * });
+   * ```
+   */
+  async invoke(options: PromptExecuteOptions) {
+    const req = this._getExecuteReq(options);
+    const resp = await this._api.executePrompt(req);
+
+    return resp.data;
+  }
+
+  /**
+   * Streaming-invoke prompt-as-a-service
+   *
+   * @param options {@link PromptExecuteOptions}
+   *
+   * @example
+   * ```typescript
+   *
+   * // 1. stream with messages
+   * const model = new PromptAsAService({});
+   *
+   * const replyStream = await model.invoke({
+   *   messages: [
+   *     { role: 'user', content: 'hi' },
+   *   ],
+   * });
+   *
+   * for await (const chunk of replyStream) {
+   *   // chunk is {@link PromptExecuteOptions}
+   * }
+   *
+   * ```
+   */
+  async stream(options: PromptExecuteOptions) {
+    const req = this._getExecuteReq(options);
+    const resp = await this._api.streamingExecutePrompt(req);
+
+    return resp;
+  }
+}
diff --git a/packages/cozeloop-ai/src/prompt/trace.ts b/packages/cozeloop-ai/src/prompt/trace.ts
index 965afe7..ba3365c 100644
--- a/packages/cozeloop-ai/src/prompt/trace.ts
+++ b/packages/cozeloop-ai/src/prompt/trace.ts
@@ -1,7 +1,7 @@
 // Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 // SPDX-License-Identifier: MIT
 import { serializeTagValue } from '../tracer/utils';
-import { type PromptQuery, type TemplateMessage } from '../api';
+import { type PromptQuery, type LoopMessage } from '../api';
 import { type Message, type PromptVariables } from './types';
 
 export function toPromptHubInput({ prompt_key, version, label }: PromptQuery) {
@@ -13,7 +13,7 @@ export function toPromptHubInput({ prompt_key, version, label }: PromptQuery) {
 }
 
 export function toPromptTemplateInput(
-  messages?: TemplateMessage[],
+  messages?: LoopMessage[],
   variables?: PromptVariables,
 ) {
   return serializeTagValue({
diff --git a/packages/cozeloop-ai/src/prompt/types.ts b/packages/cozeloop-ai/src/prompt/types.ts
index 8059cd4..a5705ca 100644
--- a/packages/cozeloop-ai/src/prompt/types.ts
+++ b/packages/cozeloop-ai/src/prompt/types.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: MIT
 import { type SimpleLogger } from '../utils/logger';
 import {
+  type PromptQuery,
   type ApiClient,
   type ApiClientOptions,
   type VariableDef,
@@ -14,12 +15,6 @@ export interface PromptCacheOptions {
   maxSize?: number;
 }
 
-export interface Message {
-  role: 'system' | 'user' | 'assistant';
-  content: string;
-  parts?: (ContentPartText | ContentPartImage)[];
-}
-
 export interface ContentPartText {
   type: 'text';
   text: string;
@@ -35,6 +30,24 @@ export interface ContentPartImage {
 
 export type ContentPart = ContentPartText | ContentPartImage;
 
+export interface ToolCall {
+  id?: string;
+  type?: 'function';
+  function: {
+    name?: string;
+    arguments?: string;
+  };
+}
+
+export interface Message {
+  role: 'system' | 'user' | 'tool' | 'assistant';
+  content?: string;
+  parts?: (ContentPartText | ContentPartImage)[];
+  reasoning_content?: string;
+  tool_call_id?: string;
+  tool_calls?: ToolCall[];
+}
+
 export interface PromptHubOptions {
   /** Workspace ID, use process.env.COZELOOP_WORKSPACE_ID when unprovided */
   workspaceId?: string;
@@ -67,3 +80,25 @@ export type PromptVariableMap = Record<
   | { def: VariableDef; value?: PromptVariables[keyof PromptVariables] }
   | undefined
 >;
+
+export interface PromptAsAServiceOptions {
+  /** Workspace ID, use process.env.COZELOOP_WORKSPACE_ID when unprovided */
+  workspaceId?: string;
+  /** The Loop {@link ApiClient} instance or {@link ApiClientOptions} */
+  apiClient?: ApiClient | ApiClientOptions;
+  /** Prompt identified by prompt query */
+  prompt?: PromptQuery;
+  /** Enable trace report for `invoke` and `stream` */
+  // traceable?: boolean;
+  /** A logger function to print debug message */
+  logger?: SimpleLogger;
+}
+
+export interface PromptExecuteOptions {
+  /** Prompt identified by prompt query */
+  prompt?: PromptQuery;
+  /** Messages */
+  messages: Message[];
+  /** variable values of Prompt */
+  variables?: PromptVariables;
+}
diff --git a/packages/cozeloop-ai/src/prompt/utils.ts b/packages/cozeloop-ai/src/prompt/utils.ts
index 7878920..f63f766 100644
--- a/packages/cozeloop-ai/src/prompt/utils.ts
+++ b/packages/cozeloop-ai/src/prompt/utils.ts
@@ -4,11 +4,11 @@ import nj from 'nunjucks';
 
 import { stringifyVal } from '../utils/common';
 import type {
-  TemplateMessage,
+  LoopMessage,
+  LoopContentPart,
   PromptQuery,
   PromptTemplate,
   VariableDef,
-  TemplateContentPart,
 } from '../api';
 import {
   type Message,
@@ -94,15 +94,15 @@ export function formatPromptTemplate(
 }
 
 function formatPart(
-  part: TemplateContentPart,
+  part: LoopContentPart,
   variableMap: PromptVariableMap,
   formatText: (content: string) => string,
 ): ContentPart[] {
   switch (part.type) {
     case 'text':
-      return [{ type: 'text', text: formatText(part.text) }];
+      return [{ type: 'text', text: formatText(part.text || '') }];
     case 'multi_part_variable': {
-      const variable = variableMap[part.text];
+      const variable = variableMap[part.text ?? ''];
       if (!variable?.value) {
         return [];
       }
@@ -123,7 +123,7 @@ function formatPart(
 }
 
 function formatParts(
-  parts: TemplateContentPart[],
+  parts: LoopContentPart[],
   variableMap: PromptVariableMap,
   formatText: (content: string) => string,
 ) {
@@ -140,7 +140,7 @@ function formatParts(
 }
 
 function formatMessage(
-  message: TemplateMessage,
+  message: LoopMessage,
   variableMap: PromptVariableMap,
   formatText: (content: string) => string,
 ): Message[] {
diff --git a/packages/cozeloop-ai/tsup.config.ts b/packages/cozeloop-ai/tsup.config.ts
index c65befa..5049396 100644
--- a/packages/cozeloop-ai/tsup.config.ts
+++ b/packages/cozeloop-ai/tsup.config.ts
@@ -16,7 +16,11 @@ export default defineConfig(() => {
     tsconfig: './tsconfig.build.json',
     format: ['cjs', 'esm'],
     dts: false,
-    onSuccess: 'tsc -b ./tsconfig.typings.json',
+    onSuccess: [
+      'printf "TSC Start build \x1b[1mtypings\x1b[0m"',
+      'tsc -b ./tsconfig.typings.json',
+      'printf " ✅\n"',
+    ].join(' && '),
     env: {
       COZELOOP_VERSION: packageJson.version,
     },