SSE概述
SSE是一种基于HTTP协议的轻量级技术，允许服务器向客户端（通常是浏览器）推送实时更新的数据。通过持久化的连接实现服务器到客户端的单向数据流。大致步骤如下：
（1）客户端通过HTTP请求向服务器发起SSE连接，并保持长连接；
（2）客户端新建连接，向服务端请求列出工具和携带参数请求执行工具等操作；
（3）服务端通过首次长连接返回执行结果；
包含：请求用户、客户端、服务端、大模型，描述完整MCP SSE过程。
过程描述：
0、编写MCP Server工具，使用Python通过装饰器将工具注册到Server端上；
1、MCP Client对Server发送请求，GET方式请求/sse，并保持长连接状态等待数据实时返回；
2、Server端返回sessionID；
3、Client发送initialize包含协商信息；
4、Server端响应确认；
5、Client发送initialized确认；
6、用户在客户端请求提问：杭州天气；
7、Client发起向Server端的tools/list请求；
8、Server端返回注册好的工具列表及所需参数；
9、Client封装请求内容：
{
"messages": [
{
"role": "user",
"content": "杭州的天气"
}
],
"model": "gpt-4o-mini",
"max_tokens": 1000,
"tools": [
{
"type": "function",
"function": {
"name": "get_weather",
"description": "获取指定城市的天气信息",
"parameters": {
"properties": {
"city": {
"title": "City",
"type": "string"
}
},
"required": [
"city"
],
"title": "get_weatherArguments",
"type": "object"
}
}
},
{
"type": "function",
"function": {
"name": "suggest_activity",
"description": "根据天气描述推荐适合的活动",
"parameters": {
"properties": {
"condition": {
"title": "Condition",
"type": "string"
}
},
"required": [
"condition"
],
"title": "suggest_activityArguments",
"type": "object"
}
}
}
]
}
10、Client将以上内容发送大模型调用API请求；
11、大模型返回tool_calls内容；
{
"id": "chatcmpl-BWdzaegB1h3XJMc4ZcgL4TWR3wmcr",
"model": "gpt-4o-mini-2024-07-18",
"object": "chat.completion",
"created": 1747119926,
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"tool_calls": [
{
"id": "call_OaxrnCKcBANGqm4mheSd9RSD",
"type": "function",
"function": {
"name": "get_weather",
"arguments": "{\"city\":\"杭州\"}"
}
}
]
},
"finish_reason": "tool_calls"
}
],
"system_fingerprint": "fp_7a53abb7a2",
"usage": {
"prompt_tokens": 88,
"completion_tokens": 15,
"total_tokens": 103,
"prompt_tokens_details": {
"audio_tokens": 0,
"cached_tokens": 0
},
"completion_tokens_details": {
"accepted_prediction_tokens": 0,
"audio_tokens": 0,
"reasoning_tokens": 0,
"rejected_prediction_tokens": 0
}
}
}
12、Client将大模型返回的name和arguments内容，POST请求Server；
13、Server接受参数执行对应的工具，并通过第一次长连接返回数据；
14、Client第二次将返回结果发送大模型调用API请求；
{
"messages": [
{
"role": "user",
"content": "杭州的天气"
},
{
"role": "assistant",
"content": null,
"tool_calls": [
{
"id": "call_4Sbmkb2kNltmzVMkJJDDgGKd",
"function": {
"arguments": "{\"city\":\"杭州\"}",
"name": "get_weather"
},
"type": "function"
}
]
},
{
"role": "tool",
"tool_call_id": "call_4Sbmkb2kNltmzVMkJJDDgGKd",
"content": "杭州：晴，25°C"
}
],
"model": "gpt-4o-mini",
"max_tokens": 1000
}
15、大模型返回结果，最终客户端将content内容返回给用户；
{
"id": "chatcmpl-BWe2yvHUm17yPRxTRuUS1FCYezPn2",
"model": "gpt-4o-mini-2024-07-18",
"object": "chat.completion",
"created": 1747120136,
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "杭州的天气是晴，气温25°C。"
},
"finish_reason": "stop"
}
],
"system_fingerprint": "fp_7a53abb7a2",
"usage": {
"prompt_tokens": 38,
"completion_tokens": 12,
"total_tokens": 50,
"prompt_tokens_details": {
"audio_tokens": 0,
"cached_tokens": 0
},
"completion_tokens_details": {
"accepted_prediction_tokens": 0,
"audio_tokens": 0,
"reasoning_tokens": 0,
"rejected_prediction_tokens": 0
}
}
} 
