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

# MCPConnection

> Protocol-neutral API for one MCP server connection

```ts theme={null}
import { MCPClient, type MCPConnection } from "@mcp-use/client";

const connection = await client.connect("demo");
```

One API for legacy sessionful (v1) and modern sessionless (v2) servers. Create connections via `MCPClient.connect()` — do not construct directly unless using low-level connectors.

`MCPSession` is a deprecated alias for `MCPConnection`.

## Metadata

```ts theme={null}
connection.info.protocolEra   // "legacy" | "modern"
connection.info.protocolVersion
connection.info.server          // { name, version, title, ... }
connection.info.capabilities
connection.info.instructions
connection.info.extensions
connection.authorization             // optional mixed-auth state
connection.info.authorization        // same state in the metadata snapshot
await connection.discoverAuthorization() // populate optional mixed-auth state
connection.supports("sampling") // capability check
```

## Lifecycle

| Method                    | Description                                                 |
| ------------------------- | ----------------------------------------------------------- |
| `connect()`               | Start transport                                             |
| `initialize()`            | Run MCP init handshake                                      |
| `discoverAuthorization()` | Discover optional mixed-auth metadata without forcing login |
| `authenticate()`          | Start optional OAuth for a connected mixed-auth server      |
| `disconnect()`            | Close transport                                             |

## Tools

| Method                            | Description     |
| --------------------------------- | --------------- |
| `listTools(options?)`             | Fetch tool list |
| `callTool(name, args?, options?)` | Invoke a tool   |

## Resources

| Method                                   | Description          |
| ---------------------------------------- | -------------------- |
| `listResources(cursor?, options?)`       | Paginated list       |
| `listAllResources(options?)`             | All resources        |
| `listResourceTemplates(options?)`        | Template list        |
| `readResource(uri, options?)`            | Read by URI          |
| `subscribeToResource(uri, options?)`     | Subscribe to updates |
| `unsubscribeFromResource(uri, options?)` | Unsubscribe          |

## Prompts

| Method                  | Description                 |
| ----------------------- | --------------------------- |
| `listPrompts()`         | List prompts                |
| `getPrompt(name, args)` | Fetch prompt with arguments |

## Completions

| Method             | Description                            |
| ------------------ | -------------------------------------- |
| `complete(params)` | Autocomplete prompt/resource arguments |

## Roots & notifications

| Method                        | Description                       |
| ----------------------------- | --------------------------------- |
| `setRoots(roots)`             | Update roots (sends notification) |
| `getRoots()`                  | Current roots                     |
| `on("notification", handler)` | Listen for server notifications   |

## Low-level

| Method                               | Description     |
| ------------------------------------ | --------------- |
| `request(method, params?, options?)` | Raw MCP request |

## Types

```ts theme={null}
interface MCPConnectionInfo {
  protocolEra: "legacy" | "modern";
  protocolVersion: string;
  server: MCPServerInfo;
  capabilities: Record<string, unknown>;
  instructions?: string;
  extensions: Record<string, unknown>;
  authorization?: MCPAuthorizationInfo;
}

interface MCPAuthorizationInfo {
  mode: "mixed";
  authenticated: boolean;
  resource?: string;
  scopesSupported?: string[];
}

interface Root {
  uri: string;   // file://...
  name?: string;
}

type NotificationHandler = (notification: Notification) => void | Promise<void>;
```

Re-exported: `CallToolResult`, `Notification`, `Root`, `Tool`

## Related

* [`MCPClient`](/typescript/api-reference/client/mcp-client)
* [Tools guide](/typescript/client/tools)