changes
This commit is contained in:
parent
091d4654c8
commit
5938c8150e
1 changed files with 1086 additions and 454 deletions
|
|
@ -5,35 +5,42 @@ description: "Learn how to build your first client in MCP"
|
|||
|
||||
In this tutorial, you'll learn how to build a client application that connects to MCP servers. It helps to have gone through the [Quickstart tutorial](/quickstart) that guides you through the basic of building your first server.
|
||||
|
||||
<Tabs>
|
||||
<Tab title="Python">
|
||||
|
||||
## System Requirements
|
||||
|
||||
Before starting, ensure your system meets these requirements:
|
||||
- Mac or Windows computer
|
||||
- Latest Python version installed
|
||||
- Latest version of `uv` installed
|
||||
|
||||
## Setting Up Your Environment
|
||||
|
||||
First, create and activate a virtual environment:
|
||||
First, create a new Python project with `uv`:
|
||||
|
||||
```bash
|
||||
# Install virtualenv if needed
|
||||
pip install virtualenv
|
||||
|
||||
# Create project directory
|
||||
mkdir mcp-client
|
||||
uv init mcp-client
|
||||
cd mcp-client
|
||||
|
||||
# Create virtual environment
|
||||
python -m virtualenv venv
|
||||
uv venv
|
||||
|
||||
# Activate virtual environment
|
||||
# On Windows:
|
||||
venv\Scripts\activate
|
||||
.venv\Scripts\activate
|
||||
# On Unix or MacOS:
|
||||
source venv/bin/activate
|
||||
source .venv/bin/activate
|
||||
|
||||
# Install required packages
|
||||
pip install mcp anthropic python-dotenv
|
||||
uv add mcp anthropic python-dotenv
|
||||
|
||||
# Remove boilerplate files
|
||||
rm hello.py
|
||||
|
||||
# Create our main file
|
||||
touch client.py
|
||||
```
|
||||
|
||||
## Setting Up Your API Key
|
||||
|
|
@ -57,9 +64,14 @@ Add `.env` to your `.gitignore`:
|
|||
echo ".env" >> .gitignore
|
||||
```
|
||||
|
||||
<Warning>
|
||||
Make sure you keep your `ANTHROPIC_API_KEY` secure!
|
||||
</Warning>
|
||||
|
||||
## Creating the Client
|
||||
|
||||
Let's create a Python client that can connect to any MCP server. We'll call it `client.py`:
|
||||
### Basic Client Structure
|
||||
First, let's set up our imports and create the basic client class:
|
||||
|
||||
```python
|
||||
import asyncio
|
||||
|
|
@ -80,110 +92,144 @@ class MCPClient:
|
|||
self.session: Optional[ClientSession] = None
|
||||
self.exit_stack = AsyncExitStack()
|
||||
self.anthropic = Anthropic()
|
||||
# methods will go here
|
||||
```
|
||||
|
||||
async def connect_to_server(self, server_script_path: str):
|
||||
"""Connect to an MCP server"""
|
||||
server_params = StdioServerParameters(
|
||||
command="python",
|
||||
args=[server_script_path],
|
||||
env=None
|
||||
)
|
||||
|
||||
stdio_transport = await self.exit_stack.enter_async_context(stdio_client(server_params))
|
||||
self.stdio, self.write = stdio_transport
|
||||
self.session = await self.exit_stack.enter_async_context(ClientSession(self.stdio, self.write))
|
||||
|
||||
await self.session.initialize()
|
||||
|
||||
# List available tools
|
||||
response = await self.session.list_tools()
|
||||
tools = response.tools
|
||||
print("\nConnected to server with tools:", [tool.name for tool in tools])
|
||||
### Server Connection Management
|
||||
|
||||
async def process_query(self, query: str) -> str:
|
||||
"""Process a query using Claude and available tools"""
|
||||
messages = [
|
||||
{
|
||||
"role": "user",
|
||||
"content": query
|
||||
}
|
||||
]
|
||||
Next, we'll implement the method to connect to an MCP server:
|
||||
|
||||
response = await self.session.list_tools()
|
||||
available_tools = [{
|
||||
"name": tool.name,
|
||||
"description": tool.description,
|
||||
"input_schema": tool.inputSchema
|
||||
} for tool in response.tools]
|
||||
|
||||
# Initial Claude API call
|
||||
response = self.anthropic.messages.create(
|
||||
model="claude-3-5-sonnet-20241022",
|
||||
max_tokens=1000,
|
||||
messages=messages,
|
||||
tools=available_tools
|
||||
)
|
||||
|
||||
# Process response and handle tool calls
|
||||
tool_results = []
|
||||
final_text = []
|
||||
|
||||
for content in response.content:
|
||||
if content.type == 'text':
|
||||
final_text.append(content.text)
|
||||
elif content.type == 'tool_use':
|
||||
tool_name = content.name
|
||||
tool_args = content.input
|
||||
|
||||
# Execute tool call
|
||||
result = await self.session.call_tool(tool_name, tool_args)
|
||||
tool_results.append({"call": tool_name, "result": result})
|
||||
final_text.append(f"[Calling tool {tool_name} with args {tool_args}]")
|
||||
|
||||
# Continue conversation with tool results
|
||||
if hasattr(content, 'text') and content.text:
|
||||
messages.append({
|
||||
"role": "assistant",
|
||||
"content": content.text
|
||||
})
|
||||
messages.append({
|
||||
"role": "user",
|
||||
"content": result.content
|
||||
})
|
||||
|
||||
# Get next response from Claude
|
||||
response = self.anthropic.messages.create(
|
||||
model="claude-3-5-sonnet-20241022",
|
||||
max_tokens=1000,
|
||||
messages=messages,
|
||||
)
|
||||
|
||||
final_text.append(response.content[0].text)
|
||||
|
||||
return "\n".join(final_text)
|
||||
|
||||
async def chat_loop(self):
|
||||
"""Run an interactive chat loop"""
|
||||
print("\nMCP Client Started!")
|
||||
print("Type your queries or 'quit' to exit.")
|
||||
|
||||
while True:
|
||||
try:
|
||||
query = input("\nQuery: ").strip()
|
||||
|
||||
if query.lower() == 'quit':
|
||||
break
|
||||
|
||||
response = await self.process_query(query)
|
||||
print("\n" + response)
|
||||
|
||||
except Exception as e:
|
||||
print(f"\nError: {str(e)}")
|
||||
```python
|
||||
async def connect_to_server(self, server_script_path: str):
|
||||
"""Connect to an MCP server
|
||||
|
||||
async def cleanup(self):
|
||||
"""Clean up resources"""
|
||||
await self.exit_stack.aclose()
|
||||
Args:
|
||||
server_script_path: Path to the server script (.py or .js)
|
||||
"""
|
||||
is_python = server_script_path.endswith('.py')
|
||||
is_js = server_script_path.endswith('.js')
|
||||
if not (is_python or is_js):
|
||||
raise ValueError("Server script must be a .py or .js file")
|
||||
|
||||
command = "python" if is_python else "node"
|
||||
server_params = StdioServerParameters(
|
||||
command=command,
|
||||
args=[server_script_path],
|
||||
env=None
|
||||
)
|
||||
|
||||
stdio_transport = await self.exit_stack.enter_async_context(stdio_client(server_params))
|
||||
self.stdio, self.write = stdio_transport
|
||||
self.session = await self.exit_stack.enter_async_context(ClientSession(self.stdio, self.write))
|
||||
|
||||
await self.session.initialize()
|
||||
|
||||
# List available tools
|
||||
response = await self.session.list_tools()
|
||||
tools = response.tools
|
||||
print("\nConnected to server with tools:", [tool.name for tool in tools])
|
||||
```
|
||||
|
||||
### Query Processing Logic
|
||||
|
||||
Now let's add the core functionality for processing queries and handling tool calls:
|
||||
|
||||
```python
|
||||
async def process_query(self, query: str) -> str:
|
||||
"""Process a query using Claude and available tools"""
|
||||
messages = [
|
||||
{
|
||||
"role": "user",
|
||||
"content": query
|
||||
}
|
||||
]
|
||||
|
||||
response = await self.session.list_tools()
|
||||
available_tools = [{
|
||||
"name": tool.name,
|
||||
"description": tool.description,
|
||||
"input_schema": tool.inputSchema
|
||||
} for tool in response.tools]
|
||||
|
||||
# Initial Claude API call
|
||||
response = self.anthropic.messages.create(
|
||||
model="claude-3-5-sonnet-20241022",
|
||||
max_tokens=1000,
|
||||
messages=messages,
|
||||
tools=available_tools
|
||||
)
|
||||
|
||||
# Process response and handle tool calls
|
||||
tool_results = []
|
||||
final_text = []
|
||||
|
||||
for content in response.content:
|
||||
if content.type == 'text':
|
||||
final_text.append(content.text)
|
||||
elif content.type == 'tool_use':
|
||||
tool_name = content.name
|
||||
tool_args = content.input
|
||||
|
||||
# Execute tool call
|
||||
result = await self.session.call_tool(tool_name, tool_args)
|
||||
tool_results.append({"call": tool_name, "result": result})
|
||||
final_text.append(f"[Calling tool {tool_name} with args {tool_args}]")
|
||||
|
||||
# Continue conversation with tool results
|
||||
if hasattr(content, 'text') and content.text:
|
||||
messages.append({
|
||||
"role": "assistant",
|
||||
"content": content.text
|
||||
})
|
||||
messages.append({
|
||||
"role": "user",
|
||||
"content": result.content
|
||||
})
|
||||
|
||||
# Get next response from Claude
|
||||
response = self.anthropic.messages.create(
|
||||
model="claude-3-5-sonnet-20241022",
|
||||
max_tokens=1000,
|
||||
messages=messages,
|
||||
)
|
||||
|
||||
final_text.append(response.content[0].text)
|
||||
|
||||
return "\n".join(final_text)
|
||||
```
|
||||
|
||||
### Interactive Chat Interface
|
||||
Now we'll add the chat loop and cleanup functionality:
|
||||
|
||||
```python
|
||||
async def chat_loop(self):
|
||||
"""Run an interactive chat loop"""
|
||||
print("\nMCP Client Started!")
|
||||
print("Type your queries or 'quit' to exit.")
|
||||
|
||||
while True:
|
||||
try:
|
||||
query = input("\nQuery: ").strip()
|
||||
|
||||
if query.lower() == 'quit':
|
||||
break
|
||||
|
||||
response = await self.process_query(query)
|
||||
print("\n" + response)
|
||||
|
||||
except Exception as e:
|
||||
print(f"\nError: {str(e)}")
|
||||
|
||||
async def cleanup(self):
|
||||
"""Clean up resources"""
|
||||
await self.exit_stack.aclose()
|
||||
```
|
||||
|
||||
### Main Entry Point
|
||||
|
||||
Finally, we'll add the main execution logic:
|
||||
|
||||
```python
|
||||
async def main():
|
||||
if len(sys.argv) < 2:
|
||||
print("Usage: python client.py <path_to_server_script>")
|
||||
|
|
@ -201,31 +247,62 @@ if __name__ == "__main__":
|
|||
asyncio.run(main())
|
||||
```
|
||||
|
||||
## Understanding the Client Code
|
||||
You can find the complete `client.py` file [here.](https://gist.github.com/zckly/f3f28ea731e096e53b39b47bf0a2d4b1)
|
||||
|
||||
Let's break down the key components of our MCP client:
|
||||
## Key Components Explained
|
||||
|
||||
1. **MCPClient Class**
|
||||
- Manages the connection to the MCP server
|
||||
- Handles communication between Claude and the server's tools
|
||||
- Maintains the chat session
|
||||
### 1. Client Initialization
|
||||
- The `MCPClient` class initializes with session management and API clients
|
||||
- Uses `AsyncExitStack` for proper resource management
|
||||
- Configures the Anthropic client for Claude interactions
|
||||
|
||||
2. **Key Methods**
|
||||
- `connect_to_server()`: Establishes connection with an MCP server
|
||||
- `process_query()`: Handles user queries by:
|
||||
- Getting available tools from the server
|
||||
- Sending the query to Claude with tool information
|
||||
- Executing any tool calls Claude requests
|
||||
- Processing Claude's responses
|
||||
- `chat_loop()`: Runs the interactive chat interface
|
||||
- `cleanup()`: Properly closes connections and resources
|
||||
### 2. Server Connection
|
||||
- Supports both Python and Node.js servers
|
||||
- Validates server script type
|
||||
- Sets up proper communication channels
|
||||
- Initializes the session and lists available tools
|
||||
|
||||
### 3. Query Processing
|
||||
- Maintains conversation context
|
||||
- Handles Claude's responses and tool calls
|
||||
- Manages the message flow between Claude and tools
|
||||
- Combines results into a coherent response
|
||||
|
||||
### 4. Interactive Interface
|
||||
- Provides a simple command-line interface
|
||||
- Handles user input and displays responses
|
||||
- Includes basic error handling
|
||||
- Allows graceful exit
|
||||
|
||||
### 5. Resource Management
|
||||
- Proper cleanup of resources
|
||||
- Error handling for connection issues
|
||||
- Graceful shutdown procedures
|
||||
|
||||
## Common Customization Points
|
||||
|
||||
1. **Tool Handling**
|
||||
- Modify `process_query()` to handle specific tool types
|
||||
- Add custom error handling for tool calls
|
||||
- Implement tool-specific response formatting
|
||||
|
||||
2. **Response Processing**
|
||||
- Customize how tool results are formatted
|
||||
- Add response filtering or transformation
|
||||
- Implement custom logging
|
||||
|
||||
3. **User Interface**
|
||||
- Add a GUI or web interface
|
||||
- Implement rich console output
|
||||
- Add command history or auto-completion
|
||||
|
||||
## Running the Client
|
||||
|
||||
To run your client with any MCP server:
|
||||
|
||||
```bash
|
||||
python client.py path/to/server.py
|
||||
uv run client.py path/to/server.py # python server
|
||||
uv run client.py path/to/build/index.js # node server
|
||||
```
|
||||
|
||||
The client will:
|
||||
|
|
@ -236,6 +313,12 @@ The client will:
|
|||
- See tool executions
|
||||
- Get responses from Claude
|
||||
|
||||
Here's an example of what it should look like if connected to the weather server from the quickstart:
|
||||
|
||||
<Frame>
|
||||
<img src="/images/client-claude-cli-python.png" />
|
||||
</Frame>
|
||||
|
||||
## How It Works
|
||||
|
||||
When you submit a query:
|
||||
|
|
@ -248,7 +331,7 @@ When you submit a query:
|
|||
6. Claude provides a natural language response
|
||||
7. The response is displayed to you
|
||||
|
||||
## Best Practices
|
||||
## Best practices
|
||||
|
||||
1. **Error Handling**
|
||||
- Always wrap tool calls in try-catch blocks
|
||||
|
|
@ -265,17 +348,532 @@ When you submit a query:
|
|||
- Validate server responses
|
||||
- Be cautious with tool permissions
|
||||
|
||||
## Next Steps
|
||||
## Troubleshooting
|
||||
|
||||
Now that you have a basic MCP client, you can:
|
||||
1. Add support for different server types
|
||||
2. Enhance error handling and recovery
|
||||
3. Implement more sophisticated conversation handling
|
||||
4. Add authentication and security features
|
||||
5. Create a better user interface
|
||||
### Server Path Issues
|
||||
- Double-check the path to your server script is correct
|
||||
- Use the absolute path if the relative path isn't working
|
||||
- For Windows users, make sure to use forward slashes (/) or escaped backslashes (\\) in the path
|
||||
- Verify the server file has the correct extension (.py for Python or .js for Node.js)
|
||||
|
||||
## Resources
|
||||
Example of correct path usage:
|
||||
```bash
|
||||
# Relative path
|
||||
uv run client.py ./server/weather.py
|
||||
|
||||
- [MCP Documentation](https://modelcontextprotocol.github.io/)
|
||||
- [Claude API Documentation](https://docs.anthropic.com/claude/reference)
|
||||
- [Tool Use Guide](https://docs.anthropic.com/claude/docs/function-calling)
|
||||
# Absolute path
|
||||
uv run client.py /Users/username/projects/mcp-server/weather.py
|
||||
|
||||
# Windows path (either format works)
|
||||
uv run client.py C:/projects/mcp-server/weather.py
|
||||
uv run client.py C:\\projects\\mcp-server\\weather.py
|
||||
```
|
||||
|
||||
### Response Timing
|
||||
- The first response might take up to 30 seconds to return
|
||||
- This is normal and happens while:
|
||||
- The server initializes
|
||||
- Claude processes the query
|
||||
- Tools are being executed
|
||||
- Subsequent responses are typically faster
|
||||
- Don't interrupt the process during this initial waiting period
|
||||
|
||||
### Common Error Messages
|
||||
|
||||
If you see:
|
||||
- `FileNotFoundError`: Check your server path
|
||||
- `Connection refused`: Ensure the server is running and the path is correct
|
||||
- `Tool execution failed`: Verify the tool's required environment variables are set
|
||||
- `Timeout error`: Consider increasing the timeout in your client configuration
|
||||
|
||||
</Tab>
|
||||
<Tab title="Node">
|
||||
## System Requirements
|
||||
|
||||
Before starting, ensure your system meets these requirements:
|
||||
- Mac or Windows computer
|
||||
- Node.js version 16 or higher installed
|
||||
- npm (comes with Node.js)
|
||||
|
||||
## Setting Up Your Environment
|
||||
|
||||
First, create a new Node.js project:
|
||||
|
||||
```bash
|
||||
# Create project directory
|
||||
mkdir mcp-client
|
||||
cd mcp-client
|
||||
|
||||
# Initialize npm project
|
||||
npm init -y
|
||||
|
||||
# Install dependencies
|
||||
npm install @modelcontextprotocol/sdk @anthropic-ai/sdk dotenv
|
||||
npm install -D typescript @types/node
|
||||
|
||||
# Create TypeScript config
|
||||
npx tsc --init
|
||||
|
||||
# Create necessary files
|
||||
mkdir src
|
||||
touch src/client.ts
|
||||
touch .env
|
||||
```
|
||||
|
||||
Update your `package.json` to add necessary configuration:
|
||||
|
||||
```json
|
||||
{
|
||||
"type": "module",
|
||||
"scripts": {
|
||||
"build": "tsc",
|
||||
"start": "node build/client.js"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Update your `tsconfig.json` with appropriate settings:
|
||||
|
||||
```json
|
||||
{
|
||||
"compilerOptions": {
|
||||
"target": "ES2022",
|
||||
"module": "Node16",
|
||||
"moduleResolution": "Node16",
|
||||
"outDir": "./build",
|
||||
"rootDir": "./src",
|
||||
"strict": true,
|
||||
"esModuleInterop": true,
|
||||
"skipLibCheck": true,
|
||||
"forceConsistentCasingInFileNames": true
|
||||
},
|
||||
"include": ["src/**/*"]
|
||||
}
|
||||
```
|
||||
|
||||
## Setting Up Your API Key
|
||||
|
||||
You'll need an Anthropic API key from the [Anthropic Console](https://console.anthropic.com/settings/keys).
|
||||
|
||||
Create a `.env` file:
|
||||
```bash
|
||||
ANTHROPIC_API_KEY=your_key_here
|
||||
```
|
||||
|
||||
Add `.env` to your `.gitignore`:
|
||||
```bash
|
||||
echo ".env" >> .gitignore
|
||||
```
|
||||
|
||||
## Creating the Client
|
||||
|
||||
First, let's set up our imports and create the basic client class in `src/client.ts`:
|
||||
|
||||
```typescript
|
||||
import { Client } from "@modelcontextprotocol/sdk/client/index.js";
|
||||
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
|
||||
import Anthropic from "@anthropic-ai/sdk";
|
||||
import dotenv from "dotenv";
|
||||
import { Tool } from "@anthropic-ai/sdk/resources/messages.js";
|
||||
import {
|
||||
CallToolResultSchema,
|
||||
ListToolsResultSchema,
|
||||
} from "@modelcontextprotocol/sdk/types.js";
|
||||
import * as readline from "node:readline";
|
||||
|
||||
dotenv.config();
|
||||
|
||||
interface MCPClientConfig {
|
||||
name?: string;
|
||||
version?: string;
|
||||
}
|
||||
|
||||
class MCPClient {
|
||||
private client: Client | null = null;
|
||||
private anthropic: Anthropic;
|
||||
private transport: StdioClientTransport | null = null;
|
||||
|
||||
constructor(config: MCPClientConfig = {}) {
|
||||
this.anthropic = new Anthropic();
|
||||
}
|
||||
|
||||
// Methods will go here
|
||||
}
|
||||
```
|
||||
|
||||
## Server Connection Management
|
||||
|
||||
Next, implement the method to connect to an MCP server:
|
||||
|
||||
```typescript
|
||||
async connectToServer(serverScriptPath: string): Promise<void> {
|
||||
const isPython = serverScriptPath.endsWith(".py");
|
||||
const isJs = serverScriptPath.endsWith(".js");
|
||||
|
||||
if (!isPython && !isJs) {
|
||||
throw new Error("Server script must be a .py or .js file");
|
||||
}
|
||||
|
||||
const command = isPython ? "python" : "node";
|
||||
|
||||
this.transport = new StdioClientTransport({
|
||||
command,
|
||||
args: [serverScriptPath],
|
||||
});
|
||||
|
||||
this.client = new Client(
|
||||
{
|
||||
name: "mcp-client",
|
||||
version: "1.0.0",
|
||||
},
|
||||
{
|
||||
capabilities: {},
|
||||
}
|
||||
);
|
||||
|
||||
await this.client.connect(this.transport);
|
||||
|
||||
// List available tools
|
||||
const response = await this.client.request(
|
||||
{ method: "tools/list" },
|
||||
ListToolsResultSchema
|
||||
);
|
||||
|
||||
console.log(
|
||||
"\nConnected to server with tools:",
|
||||
response.tools.map((tool: any) => tool.name)
|
||||
);
|
||||
}
|
||||
```
|
||||
|
||||
## Query Processing Logic
|
||||
|
||||
Now add the core functionality for processing queries and handling tool calls:
|
||||
|
||||
```typescript
|
||||
async processQuery(query: string): Promise<string> {
|
||||
if (!this.client) {
|
||||
throw new Error("Client not connected");
|
||||
}
|
||||
|
||||
// Initialize messages array with user query
|
||||
let messages: Anthropic.MessageParam[] = [
|
||||
{
|
||||
role: "user",
|
||||
content: query,
|
||||
},
|
||||
];
|
||||
|
||||
// Get available tools
|
||||
const toolsResponse = await this.client.request(
|
||||
{ method: "tools/list" },
|
||||
ListToolsResultSchema
|
||||
);
|
||||
|
||||
const availableTools: Tool[] = toolsResponse.tools.map((tool: any) => ({
|
||||
name: tool.name,
|
||||
description: tool.description,
|
||||
input_schema: tool.inputSchema,
|
||||
}));
|
||||
|
||||
const finalText: string[] = [];
|
||||
let currentResponse = await this.anthropic.messages.create({
|
||||
model: "claude-3-5-sonnet-20241022",
|
||||
max_tokens: 1000,
|
||||
messages,
|
||||
tools: availableTools,
|
||||
});
|
||||
|
||||
// Process the response and any tool calls
|
||||
while (true) {
|
||||
// Add Claude's response to final text and messages
|
||||
for (const content of currentResponse.content) {
|
||||
if (content.type === "text") {
|
||||
finalText.push(content.text);
|
||||
} else if (content.type === "tool_use") {
|
||||
const toolName = content.name;
|
||||
const toolArgs = content.input;
|
||||
|
||||
// Execute tool call
|
||||
const result = await this.client.request(
|
||||
{
|
||||
method: "tools/call",
|
||||
params: {
|
||||
name: toolName,
|
||||
args: toolArgs,
|
||||
},
|
||||
},
|
||||
CallToolResultSchema
|
||||
);
|
||||
|
||||
finalText.push(
|
||||
`[Calling tool ${toolName} with args ${JSON.stringify(toolArgs)}]`
|
||||
);
|
||||
|
||||
// Add Claude's response (including tool use) to messages
|
||||
messages.push({
|
||||
role: "assistant",
|
||||
content: currentResponse.content,
|
||||
});
|
||||
|
||||
// Add tool result to messages
|
||||
messages.push({
|
||||
role: "user",
|
||||
content: [
|
||||
{
|
||||
type: "tool_result",
|
||||
tool_use_id: content.id,
|
||||
content: [
|
||||
{ type: "text", text: JSON.stringify(result.content) },
|
||||
],
|
||||
},
|
||||
],
|
||||
});
|
||||
|
||||
// Get next response from Claude with tool results
|
||||
currentResponse = await this.anthropic.messages.create({
|
||||
model: "claude-3-5-sonnet-20241022",
|
||||
max_tokens: 1000,
|
||||
messages,
|
||||
tools: availableTools,
|
||||
});
|
||||
|
||||
// Add Claude's interpretation of the tool results to final text
|
||||
if (currentResponse.content[0]?.type === "text") {
|
||||
finalText.push(currentResponse.content[0].text);
|
||||
}
|
||||
|
||||
// Continue the loop to process any additional tool calls
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
// If we reach here, there were no tool calls in the response
|
||||
break;
|
||||
}
|
||||
|
||||
return finalText.join("\n");
|
||||
}
|
||||
|
||||
```
|
||||
|
||||
## Interactive Chat Interface
|
||||
|
||||
Add the chat loop and cleanup functionality:
|
||||
|
||||
```typescript
|
||||
async chatLoop(): Promise<void> {
|
||||
console.log("\nMCP Client Started!");
|
||||
console.log("Type your queries or 'quit' to exit.");
|
||||
|
||||
// Using Node's readline for console input
|
||||
const rl = readline.createInterface({
|
||||
input: process.stdin,
|
||||
output: process.stdout,
|
||||
});
|
||||
|
||||
const askQuestion = () => {
|
||||
rl.question("\nQuery: ", async (query: string) => {
|
||||
try {
|
||||
if (query.toLowerCase() === "quit") {
|
||||
await this.cleanup();
|
||||
rl.close();
|
||||
return;
|
||||
}
|
||||
|
||||
const response = await this.processQuery(query);
|
||||
console.log("\n" + response);
|
||||
askQuestion();
|
||||
} catch (error) {
|
||||
console.error("\nError:", error);
|
||||
askQuestion();
|
||||
}
|
||||
});
|
||||
};
|
||||
|
||||
askQuestion();
|
||||
}
|
||||
|
||||
async cleanup(): Promise<void> {
|
||||
if (this.transport) {
|
||||
await this.transport.close();
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Main Entry Point
|
||||
|
||||
Finally, add the main execution logic outside the class:
|
||||
|
||||
```typescript
|
||||
// Main execution
|
||||
async function main() {
|
||||
if (process.argv.length < 3) {
|
||||
console.log("Usage: ts-node client.ts <path_to_server_script>");
|
||||
process.exit(1);
|
||||
}
|
||||
|
||||
const client = new MCPClient();
|
||||
try {
|
||||
await client.connectToServer(process.argv[2]);
|
||||
await client.chatLoop();
|
||||
} catch (error) {
|
||||
console.error("Error:", error);
|
||||
await client.cleanup();
|
||||
process.exit(1);
|
||||
}
|
||||
}
|
||||
|
||||
// Run main if this is the main module
|
||||
if (import.meta.url === new URL(process.argv[1], "file:").href) {
|
||||
main();
|
||||
}
|
||||
|
||||
export default MCPClient;
|
||||
```
|
||||
|
||||
## Running the Client
|
||||
|
||||
To run your client with any MCP server:
|
||||
|
||||
```bash
|
||||
# Build the TypeScript code. Make sure to rerun this every time you update `client.ts`!
|
||||
npm run build
|
||||
|
||||
# Run the client
|
||||
node build/client.js path/to/server.py # for Python servers
|
||||
node build/client.js path/to/server.js # for Node.js servers
|
||||
```
|
||||
|
||||
The client will:
|
||||
1. Connect to the specified server
|
||||
2. List available tools
|
||||
3. Start an interactive chat session where you can:
|
||||
- Enter queries
|
||||
- See tool executions
|
||||
- Get responses from Claude
|
||||
|
||||
## Key Components Explained
|
||||
|
||||
#### 1. Client Initialization
|
||||
- The `MCPClient` class initializes with session management and API clients
|
||||
- Sets up the MCP client with basic capabilities
|
||||
- Configures the Anthropic client for Claude interactions
|
||||
|
||||
#### 2. Server Connection
|
||||
- Supports both Python and Node.js servers
|
||||
- Validates server script type
|
||||
- Sets up proper communication channels
|
||||
- Lists available tools on connection
|
||||
|
||||
#### 3. Query Processing
|
||||
- Maintains conversation context
|
||||
- Handles Claude's responses and tool calls
|
||||
- Manages the message flow between Claude and tools
|
||||
- Combines results into a coherent response
|
||||
|
||||
#### 4. Interactive Interface
|
||||
- Provides a simple command-line interface
|
||||
- Handles user input and displays responses
|
||||
- Includes basic error handling
|
||||
- Allows graceful exit
|
||||
|
||||
#### 5. Resource Management
|
||||
- Proper cleanup of resources
|
||||
- Error handling for connection issues
|
||||
- Graceful shutdown procedures
|
||||
|
||||
### Common Customization Points
|
||||
|
||||
1. **Tool Handling**
|
||||
- Modify `processQuery()` to handle specific tool types
|
||||
- Add custom error handling for tool calls
|
||||
- Implement tool-specific response formatting
|
||||
|
||||
2. **Response Processing**
|
||||
- Customize how tool results are formatted
|
||||
- Add response filtering or transformation
|
||||
- Implement custom logging
|
||||
|
||||
3. **User Interface**
|
||||
- Add a GUI or web interface
|
||||
- Implement rich console output
|
||||
- Add command history or auto-completion
|
||||
|
||||
### Best Practices
|
||||
|
||||
1. **Error Handling**
|
||||
- Always wrap tool calls in try-catch blocks
|
||||
- Provide meaningful error messages
|
||||
- Gracefully handle connection issues
|
||||
|
||||
2. **Resource Management**
|
||||
- Use proper cleanup methods
|
||||
- Close connections when done
|
||||
- Handle server disconnections
|
||||
|
||||
3. **Security**
|
||||
- Store API keys securely in `.env`
|
||||
- Validate server responses
|
||||
- Be cautious with tool permissions
|
||||
|
||||
### Troubleshooting
|
||||
|
||||
#### Server Path Issues
|
||||
- Double-check the path to your server script
|
||||
- Use absolute paths if relative paths aren't working
|
||||
- For Windows users, use forward slashes (/) or escaped backslashes (\\)
|
||||
- Verify the server file has the correct extension (.py or .js)
|
||||
|
||||
Example of correct path usage:
|
||||
```bash
|
||||
# Relative path
|
||||
node build/client.js ./server/weather.js
|
||||
|
||||
# Absolute path
|
||||
node build/client.js /Users/username/projects/mcp-server/weather.js
|
||||
|
||||
# Windows path (either format works)
|
||||
node build/client.js C:/projects/mcp-server/weather.js
|
||||
node build/client.js C:\\projects\\mcp-server\\weather.js
|
||||
```
|
||||
|
||||
#### Connection Issues
|
||||
- Verify the server script exists and has correct permissions
|
||||
- Check that the server script is executable
|
||||
- Ensure the server script's dependencies are installed
|
||||
- Try running the server script directly to check for errors
|
||||
|
||||
#### Tool Execution Issues
|
||||
- Check server logs for error messages
|
||||
- Verify tool input arguments match the schema
|
||||
- Ensure tool dependencies are available
|
||||
- Add debug logging to track execution flow
|
||||
</Tab>
|
||||
</Tabs>
|
||||
|
||||
## Next steps
|
||||
|
||||
<CardGroup cols={1}>
|
||||
<Card
|
||||
title="Building a local fileserver"
|
||||
icon="files"
|
||||
href="/examples"
|
||||
>
|
||||
Build an intermediate MCP server that communicates with your local filesystem
|
||||
</Card>
|
||||
<Card
|
||||
title="Example servers"
|
||||
icon="grid"
|
||||
href="/examples"
|
||||
>
|
||||
Check out our gallery of official MCP servers and implementations
|
||||
</Card>
|
||||
<Card
|
||||
title="Core architecture"
|
||||
icon="sitemap"
|
||||
href="/docs/concepts/architecture"
|
||||
>
|
||||
Understand how MCP connects clients, servers, and LLMs
|
||||
</Card>
|
||||
</CardGroup>
|
||||
Loading…
Reference in a new issue