提示词
提示词使服务器能够定义可重用的提示词模板和工作流,客户端可以轻松地将其呈现给用户和 LLM。它们提供了一种强大的方式来标准化和共享常见的 LLM 交互。
概述
MCP 中的提示词是预定义的模板,可以:
- 接受动态参数
- 包含来自资源的上下文
- 链接多个交互
- 引导特定工作流
- 作为 UI 元素呈现(如斜杠命令)
提示词结构
每个提示词的定义结构如下:
{
name: string; // 提示词的唯一标识符
description?: string; // 人类可读的描述
arguments?: [ // 可选的参数列表
{
name: string; // 参数标识符
description?: string; // 参数描述
required?: boolean; // 参数是否必需
}
]
}发现提示词
客户端可以通过 prompts/list 端点发现可用的提示词:
// 请求
{
method: "prompts/list"
}
// 响应
{
prompts: [
{
name: "analyze-code",
description: "分析代码以寻找潜在的改进",
arguments: [
{
name: "language",
description: "编程语言",
required: true
}
]
}
]
}使用提示词
要使用提示词,客户端需要发送 prompts/get 请求:
// 请求
{
method: "prompts/get",
params: {
name: "analyze-code",
arguments: {
language: "python"
}
}
}
// 响应
{
description: "分析 Python 代码以寻找潜在的改进",
messages: [
{
role: "user",
content: {
type: "text",
text: "请分析以下 Python 代码以寻找潜在的改进:\n\n```python\ndef calculate_sum(numbers):\n total = 0\n for num in numbers:\n total = total + num\n return total\n\nresult = calculate_sum([1, 2, 3, 4, 5])\nprint(result)\n```"
}
}
]
}动态提示词
提示词可以是动态的,包括:
嵌入的资源上下文
{
"name": "analyze-project",
"description": "分析项目日志和代码",
"arguments": [
{
"name": "timeframe",
"description": "分析日志的时间段",
"required": true
},
{
"name": "fileUri",
"description": "要审查的代码文件的 URI",
"required": true
}
]
}处理 prompts/get 请求时:
{
"messages": [
{
"role": "user",
"content": {
"type": "text",
"text": "分析这些系统日志和代码文件是否存在问题:"
}
},
{
"role": "user",
"content": {
"type": "resource",
"resource": {
"uri": "logs://recent?timeframe=1h",
"text": "[2024-03-14 15:32:11] 错误: network.py:127 中的连接超时\n[2024-03-14 15:32:15] 警告: 重试连接(尝试 2/3)\n[2024-03-14 15:32:20] 错误: 超过最大重试次数",
"mimeType": "text/plain"
}
}
},
{
"role": "user",
"content": {
"type": "resource",
"resource": {
"uri": "file:///path/to/code.py",
"text": "def connect_to_service(timeout=30):\n retries = 3\n for attempt in range(retries):\n try:\n return establish_connection(timeout)\n except TimeoutError:\n if attempt == retries - 1:\n raise\n time.sleep(5)\n\ndef establish_connection(timeout):\n # 连接实现\n pass",
"mimeType": "text/x-python"
}
}
}
]
}多步工作流
const debugWorkflow = {
name: "debug-error",
async getMessages(error: string) {
return [
{
role: "user",
content: {
type: "text",
text: `我遇到了这个错误: ${error}`
}
},
{
role: "assistant",
content: {
type: "text",
text: "我来帮你分析这个错误。你目前尝试过什么方法?"
}
},
{
role: "user",
content: {
type: "text",
text: "我尝试过重启服务,但错误仍然存在。"
}
}
];
}
};实现示例
这是在 MCP 服务器中实现提示词的完整示例:
import { Server } from "@modelcontextprotocol/sdk/server";
import {
ListPromptsRequestSchema,
GetPromptRequestSchema
} from "@modelcontextprotocol/sdk/types";
const PROMPTS = {
"git-commit": {
name: "git-commit",
description: "Generate a Git commit message",
arguments: [
{
name: "changes",
description: "Git diff or description of changes",
required: true
}
]
},
"explain-code": {
name: "explain-code",
description: "Explain how code works",
arguments: [
{
name: "code",
description: "Code to explain",
required: true
},
{
name: "language",
description: "Programming language",
required: false
}
]
}
};
const server = new Server({
name: "example-prompts-server",
version: "1.0.0"
}, {
capabilities: {
prompts: {}
}
});
// List available prompts
server.setRequestHandler(ListPromptsRequestSchema, async () => {
return {
prompts: Object.values(PROMPTS)
};
});
// Get specific prompt
server.setRequestHandler(GetPromptRequestSchema, async (request) => {
const prompt = PROMPTS[request.params.name];
if (!prompt) {
throw new Error(`Prompt not found: ${request.params.name}`);
}
if (request.params.name === "git-commit") {
return {
messages: [
{
role: "user",
content: {
type: "text",
text: `Generate a concise but descriptive commit message for these changes:\n\n${request.params.arguments?.changes}`
}
}
]
};
}
if (request.params.name === "explain-code") {
const language = request.params.arguments?.language || "Unknown";
return {
messages: [
{
role: "user",
content: {
type: "text",
text: `Explain how this ${language} code works:\n\n${request.params.arguments?.code}`
}
}
]
};
}
throw new Error("Prompt implementation not found");
}); from mcp.server import Server
import mcp.types as types
# Define available prompts
PROMPTS = {
"git-commit": types.Prompt(
name="git-commit",
description="Generate a Git commit message",
arguments=[
types.PromptArgument(
name="changes",
description="Git diff or description of changes",
required=True
)
],
),
"explain-code": types.Prompt(
name="explain-code",
description="Explain how code works",
arguments=[
types.PromptArgument(
name="code",
description="Code to explain",
required=True
),
types.PromptArgument(
name="language",
description="Programming language",
required=False
)
],
)
}
# Initialize server
app = Server("example-prompts-server")
@app.list_prompts()
async def list_prompts() -> list[types.Prompt]:
return list(PROMPTS.values())
@app.get_prompt()
async def get_prompt(
name: str, arguments: dict[str, str] | None = None
) -> types.GetPromptResult:
if name not in PROMPTS:
raise ValueError(f"Prompt not found: {name}")
if name == "git-commit":
changes = arguments.get("changes") if arguments else ""
return types.GetPromptResult(
messages=[
types.PromptMessage(
role="user",
content=types.TextContent(
type="text",
text=f"Generate a concise but descriptive commit message "
f"for these changes:\n\n{changes}"
)
)
]
)
if name == "explain-code":
code = arguments.get("code") if arguments else ""
language = arguments.get("language", "Unknown") if arguments else "Unknown"
return types.GetPromptResult(
messages=[
types.PromptMessage(
role="user",
content=types.TextContent(
type="text",
text=f"Explain how this {language} code works:\n\n{code}"
)
)
]
)
raise ValueError("Prompt implementation not found")最佳实践
在实现提示词时:
- 使用清晰、描述性的提示词名称
- 为提示词和参数提供详细描述
- 验证所有必需参数
- 优雅地处理缺失参数
- 考虑提示词模板的版本控制
- 适当缓存动态内容
- 实现错误处理
- 记录预期的参数格式
- 考虑提示词的可组合性
- 使用各种输入测试提示词
UI 集成
提示词可以在客户端 UI 中呈现为:
- 斜杠命令
- 快速操作
- 上下文菜单项
- 命令面板条目
- 引导式工作流
- 交互式表单
更新和变更
服务器可以通知客户端提示词的变更:
- 服务器功能:
prompts.listChanged - 通知:
notifications/prompts/list_changed - 客户端重新获取提示词列表
安全考虑
在实现提示词时:
- 验证所有参数
- 净化用户输入
- 考虑速率限制
- 实现访问控制
- 审计提示词使用情况
- 适当处理敏感数据
- 验证生成的内容
- 实现超时
- 考虑提示词注入风险
- 记录安全要求 </rewritten_file>