sidebar_position: 3 slug: /mcp_client
Python and curl MCP client examples.
:::info IMPORTANT
If your MCP server is running in host mode, include your acquired API key in your client’s headers when connecting asynchronously to it:
async with sse_client("http://localhost:9382/sse", headers={"api_key": "YOUR_KEY_HERE"}) as streams:
# Rest of your code...
Alternatively, to comply with OAuth 2.1 Section 5, you can run the following code instead to connect to your MCP server:
async with sse_client("http://localhost:9382/sse", headers={"Authorization": "YOUR_KEY_HERE"}) as streams:
# Rest of your code...
:::
When interacting with the MCP server via HTTP requests, follow this initialization sequence:
initialize request with protocol version and capabilities.initialize response, including the supported protocol and capabilities.initialized notification.:::tip NOTE For more information about this initialization process, see here. :::
In the following sections, we will walk you through a complete tool calling process.
Each curl request with the MCP server must include a session ID:
$ curl -N -H "api_key: YOUR_API_KEY" http://127.0.0.1:9382/sse
:::tip NOTE See here for information about acquiring an API key. :::
The transport will stream messages such as tool results, server responses, and keep-alive pings.
The server returns the session ID:
event: endpoint
data: /messages/?session_id=5c6600ef61b845a788ddf30dceb25c54
Initialize requestThe client sends an initialize request with protocol version and capabilities:
session_id="5c6600ef61b845a788ddf30dceb25c54" && \
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 1,
"method": "initialize",
"params": {
"protocolVersion": "1.0",
"capabilities": {},
"clientInfo": {
"name": "ragflow-mcp-client",
"version": "0.1"
}
}
}' && \
The server replies with an initialize response, including the supported protocol and capabilities:
event: message
data: {"jsonrpc":"2.0","id":1,"result":{"protocolVersion":"2025-03-26","capabilities":{"experimental":{"headers":{"host":"127.0.0.1:9382","user-agent":"curl/8.7.1","accept":"*/*","api_key":"ragflow-xxxxxxxxxxxx","accept-encoding":"gzip"}},"tools":{"listChanged":false}},"serverInfo":{"name":"ragflow-server","version":"1.9.4"}}}
The client confirms readiness with an initialized notification:
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"method": "notifications/initialized",
"params": {}
}' && \
The connection is established between the client and the server, and further operations (such as tool listing) may proceed.
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 3,
"method": "tools/list",
"params": {}
}' && \
event: message
data: {"jsonrpc":"2.0","id":3,"result":{"tools":[{"name":"ragflow_retrieval","description":"Retrieve relevant chunks from the RAGFlow retrieve interface based on the question, using the specified dataset_ids and optionally document_ids. Below is the list of all available datasets, including their descriptions and IDs. If you're unsure which datasets are relevant to the question, simply pass all dataset IDs to the function.","inputSchema":{"type":"object","properties":{"dataset_ids":{"type":"array","items":{"type":"string"}},"document_ids":{"type":"array","items":{"type":"string"}},"question":{"type":"string"}},"required":["dataset_ids","question"]}}]}}
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 4,
"method": "tools/call",
"params": {
"name": "ragflow_retrieval",
"arguments": {
"question": "How to install neovim?",
"dataset_ids": ["DATASET_ID_HERE"],
"document_ids": []
}
}
}'
event: message
data: {"jsonrpc":"2.0","id":4,"result":{...}}
session_id="YOUR_SESSION_ID" && \
# Step 1: Initialize request
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 1,
"method": "initialize",
"params": {
"protocolVersion": "1.0",
"capabilities": {},
"clientInfo": {
"name": "ragflow-mcp-client",
"version": "0.1"
}
}
}' && \
sleep 2 && \
# Step 2: Initialized notification
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"method": "notifications/initialized",
"params": {}
}' && \
sleep 2 && \
# Step 3: Tool listing
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 3,
"method": "tools/list",
"params": {}
}' && \
sleep 2 && \
# Step 4: Tool call
curl -X POST "http://127.0.0.1:9382/messages/?session_id=$session_id" \
-H "api_key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"jsonrpc": "2.0",
"id": 4,
"method": "tools/call",
"params": {
"name": "ragflow_retrieval",
"arguments": {
"question": "How to install neovim?",
"dataset_ids": ["DATASET_ID_HERE"],
"document_ids": []
}
}
}'