Events

Dasshh uses an event-queue messaging architecture to update the UI with events.

This page lays out all the event classes available.

Note

Events in Dasshh are based on Textual's Message system

UI Events

Events related to user interface interactions and navigation.

event ChangeView

Change the view on the main screen

class ChangeView(Message)

Attributes:

Attribute	Type	Description
view	str	The name of the view to switch to

Constructor:

ChangeView(view: str)

Parameters:

Param	Default	Description
view		The target view name (e.g., "chat", "settings", "about")

Chat Events

Events related to chat interactions and session management.

event NewMessage

Send a message to the chat

class NewMessage(Message)

Attributes:

Attribute	Type	Description
message	str	The message content to send

Constructor:

NewMessage(message: str)

Parameters:

Param	Default	Description
message		The user message to send to the assistant

event NewSession

Create a new session

class NewSession(Message)

Constructor:

NewSession()

Notes: - This event triggers the creation of a new chat session - No parameters required

event LoadSession

Load a previous session

class LoadSession(Message)

Attributes:

Attribute	Type	Description
session_id	str	The ID of the session to load

Constructor:

LoadSession(session_id: str)

Parameters:

Param	Default	Description
session_id		The unique identifier of the session to load

event DeleteSession

Delete an existing session

class DeleteSession(Message)

Attributes:

Attribute	Type	Description
session_id	str	The ID of the session to delete

Constructor:

DeleteSession(session_id: str)

Parameters:

Param	Default	Description
session_id		The unique identifier of the session to delete

Assistant Runtime Events

Events related to AI assistant processing and responses.

event AssistantResponseStart

Event triggered before assistant starts processing a query

class AssistantResponseStart(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for this query invocation

Constructor:

AssistantResponseStart(invocation_id: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track this specific query through its lifecycle

event AssistantResponseUpdate

Event triggered when assistant returns a partial response (streaming)

class AssistantResponseUpdate(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for this query invocation
content	str	Partial content of the response

Constructor:

AssistantResponseUpdate(invocation_id: str, content: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track this specific query
content		The partial response content to append

event AssistantResponseComplete

Event triggered when assistant completes processing a query

class AssistantResponseComplete(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for this query invocation
content	str	Final complete content of the response

Constructor:

AssistantResponseComplete(invocation_id: str, content: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track this specific query
content		The final complete response content

event AssistantResponseError

Event triggered when assistant encounters an error

class AssistantResponseError(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for this query invocation
error	str	Error message describing what went wrong

Constructor:

AssistantResponseError(invocation_id: str, error: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track this specific query
error		Description of the error that occurred

Tool Call Events

Events related to tool execution during assistant processing.

event AssistantToolCallStart

Event triggered when assistant starts a tool call

class AssistantToolCallStart(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for the query invocation
tool_call_id	str	Unique identifier for this specific tool call
tool_name	str	Name of the tool being called
args	str	JSON string of arguments passed to the tool

Constructor:

AssistantToolCallStart(invocation_id: str, tool_call_id: str, tool_name: str, args: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track the query
tool_call_id		Unique ID for this tool call within the query
tool_name		Name of the tool being executed
args		JSON-encoded arguments being passed to the tool

event AssistantToolCallComplete

Event triggered when assistant completes a tool call

class AssistantToolCallComplete(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for the query invocation
tool_call_id	str	Unique identifier for this specific tool call
tool_name	str	Name of the tool that was called
result	str	JSON string of the tool's return value

Constructor:

AssistantToolCallComplete(invocation_id: str, tool_call_id: str, tool_name: str, result: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track the query
tool_call_id		Unique ID for this tool call within the query
tool_name		Name of the tool that was executed
result		JSON-encoded result returned by the tool

event AssistantToolCallError

Event triggered when assistant encounters an error during a tool call

class AssistantToolCallError(Message)

Attributes:

Attribute	Type	Description
invocation_id	str	Unique identifier for the query invocation
tool_call_id	str	Unique identifier for this specific tool call
tool_name	str	Name of the tool that failed
error	str	Error message describing what went wrong

Constructor:

AssistantToolCallError(invocation_id: str, tool_call_id: str, tool_name: str, error: str)

Parameters:

Param	Default	Description
invocation_id		Unique ID to track the query
tool_call_id		Unique ID for this tool call within the query
tool_name		Name of the tool that encountered an error
error		Description of the error that occurred

Event Flow

Understanding how events flow through the system:

Query Processing Flow

1. User Input: NewMessage → User types a message
2. Assistant Start: AssistantResponseStart → Processing begins
3. Streaming Updates: AssistantResponseUpdate → Partial responses (optional)
4. Tool Execution (if needed):
   • AssistantToolCallStart → Tool begins execution
   • AssistantToolCallComplete → Tool finishes successfully
   • AssistantToolCallError → Tool encounters error (alternative)
5. Assistant Complete: AssistantResponseComplete → Final response
6. Error Handling: AssistantResponseError → If processing fails (alternative)

Session Management Flow

1. Create: NewSession → Creates a new conversation
2. Load: LoadSession → Switches to existing conversation
3. Delete: DeleteSession → Removes conversation from history

UI Navigation Flow

• View Change: ChangeView → Switches between app sections (chat, settings, about)