> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agenticenv.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Client

> Build explicit MCP clients with mcpclient.NewClient and register them via WithMCPClients

Same MCP env as [MCP Config](/examples/mcp-config), but builds clients with `pkg/mcp/client` and passes them via `WithMCPClients`.

Source: [`examples/agent_with_mcp_client/`](https://github.com/agenticenv/agent-sdk-go/tree/main/examples/agent_with_mcp_client)

## What it demonstrates

* `mcpclient.NewClient` with `WithTimeout`, `WithRetryAttempts`, `WithToolFilter`
* Mixing config-based and client-based registration patterns
* Pre-built clients for custom transport wiring

## Run

From `examples/`:

```bash theme={null}
go run ./agent_with_mcp_client
go run ./agent_with_mcp_client "List tools you can call."
```

Configure `MCP_TRANSPORT`, stdio or HTTP URLs, and auth in `.env` — see [MCP Config](/examples/mcp-config) for transport details and [Configuration](/examples/configuration) for the full variable reference.

## Key code

```go theme={null}
client, err := mcpclient.NewClient(
    mcpclient.WithTransport(transport),
    mcpclient.WithTimeout(30 * time.Second),
    mcpclient.WithRetryAttempts(3),
    mcpclient.WithToolFilter(mcpclient.AllowTools("read_file", "list_directory")),
)

a, err := agent.NewAgent(
    agent.WithLLMClient(llmClient),
    agent.WithMCPClients(client),
)
```

## Expected output

```
I have access to read_file and list_directory tools from the configured MCP server.
What would you like to do?
```

## Learn more

<CardGroup cols={2}>
  <Card title="MCP" icon="plug" href="/features/mcp">
    MCP feature documentation
  </Card>

  <Card title="MCP Config" icon="gear" href="/examples/mcp-config">
    WithMCPConfig variant
  </Card>
</CardGroup>