> ## Documentation Index
> Fetch the complete documentation index at: https://gofastmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.
# messages
# `fastmcp.client.messages`
## Classes
### `MessageHandler`
This class is used to handle MCP messages sent to the client: notifications
and transport-level exceptions. Users can override any of the hooks.
Server-initiated *requests* (ping, sampling, roots) never reach this
handler: the stable MCP SDK v2's `message_handler` contract only delivers
`ServerNotification | Exception`, so a request has no wire path here.
Those are answered through the `Client`'s dedicated callbacks instead —
`sampling_handler=`, `roots=`, and `elicitation_handler=`.
**Methods:**
#### `dispatch`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
dispatch(self, message: Message) -> None
```
#### `on_message`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_message(self, message: Message) -> None
```
#### `on_notification`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_notification(self, message: mcp_types.ServerNotification) -> None
```
#### `on_exception`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_exception(self, message: Exception) -> None
```
#### `on_progress`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_progress(self, message: mcp_types.ProgressNotification) -> None
```
#### `on_logging_message`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_logging_message(self, message: mcp_types.LoggingMessageNotification) -> None
```
#### `on_tool_list_changed`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_tool_list_changed(self, message: mcp_types.ToolListChangedNotification) -> None
```
#### `on_resource_list_changed`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_resource_list_changed(self, message: mcp_types.ResourceListChangedNotification) -> None
```
#### `on_prompt_list_changed`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_prompt_list_changed(self, message: mcp_types.PromptListChangedNotification) -> None
```
#### `on_resource_updated`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_resource_updated(self, message: mcp_types.ResourceUpdatedNotification) -> None
```
#### `on_cancelled`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
on_cancelled(self, message: mcp_types.CancelledNotification) -> None
```