Classic Events

Each settings hook event is also an event named classic.<Event> for a mod. The event e is the stdin JSON of the settings hook, with the base fields. The chain is the managed settings hooks, then the hooks modules, then the other settings hooks as core. A managed block ends the chain above every module.

Remove the on call to turn a hook off. disableAllHooks stops installed mods. The same events come from hooks in settings.

Official pages: Hooks Reference, React to Events. Source: the program (the *HookInput types of types-2.1.304.d.ts). For what each event means, see Hook Events.

Example

export function register(on) {
  on('classic.PreToolUse', { tool_name: 'Bash' }, async ($, e, next) => next(e))
  on('classic.Stop', async ($, e, next) => next(e))
}

Events

Most results include block, preventContinuation, and stopReason. The table lists extra result fields when there are any.

Item	Status	Input type and fields	Result
classic.ConfigChange	Documented	ConfigChangeHookInput: hook_event_name, source, file_path	Base
classic.CwdChanged	Documented	CwdChangedHookInput: hook_event_name, old_cwd, new_cwd	Base
classic.DirectoryAdded	Documented	DirectoryAddedHookInput: hook_event_name, directory, source	Base
classic.Elicitation	Documented	ElicitationHookInput: hook_event_name, mcp_server_name, message, mode, url, elicitation_id, requested_schema. Fires when an MCP server asks for user input. Hooks can auto-respond (accept or decline) instead of showing the dialog.	Base
classic.ElicitationResult	Documented	ElicitationResultHookInput: hook_event_name, mcp_server_name, elicitation_id, mode, action, content. Fires after the user answers an MCP elicitation. Hooks can observe or override the answer before it goes to the server.	Base
classic.FileChanged	Documented	FileChangedHookInput: hook_event_name, file_path, event	Base
classic.InstructionsLoaded	Documented	InstructionsLoadedHookInput: file_path, memory_type, load_reason, globs, trigger_file_path, parent_file_path	Base
classic.MessageDisplay	Documented	MessageDisplayHookInput: hook_event_name, turn_id, message_id, index, final, delta. Fires with each batch of newly finished lines while an assistant message streams. Display only: the stored message and what the model sees stay as they are.	Base plus displayContent
classic.Notification	Documented	NotificationHookInput: hook_event_name, message, title, notification_type	Base
classic.PermissionDenied	Documented	PermissionDeniedHookInput: hook_event_name, tool_name, tool_input, tool_use_id, reason, mcp_server	Base plus retry
classic.PermissionRequest	Documented	PermissionRequestHookInput: hook_event_name, tool_name, tool_input, permission_suggestions, mcp_server	Base plus decision
classic.PostCompact	Documented	PostCompactHookInput: hook_event_name, trigger, compact_summary	Base
classic.PostModelSwitch	Documented	PostModelSwitchHookInput: includes from_model, to_model, context_tokens, pricing	Base plus additionalContext
classic.PostToolBatch	Documented	PostToolBatchHookInput: hook_event_name, tool_calls. Fires once after every tool call in a batch has resolved, before the next model request.	Base plus additionalContext
classic.PostToolUseFailure	Documented	PostToolUseFailureHookInput: includes tool_name, tool_input, error, is_interrupt	Base plus additionalContext
classic.PostToolUse	Documented	PostToolUseHookInput: includes tool_name, tool_input, tool_response, duration_ms	Base plus additionalContext, updatedToolOutput, updatedMCPToolOutput
classic.PreCompact	Documented	PreCompactHookInput: hook_event_name, trigger, custom_instructions	Base
classic.PreModelSwitch	Documented	PreModelSwitchHookInput: includes from_model, to_model, context_tokens, pricing	Base plus permissionDecision, permissionDecisionReason
classic.PreToolUse	Documented	ToolCallEnvelope (from PreToolUseHookInput)	PreToolUseResult: allow, ask, or deny
classic.SessionEnd	Documented	SessionEndHookInput: hook_event_name, reason	Base
classic.SessionStart	Documented	SessionStartHookInput: includes source, agent_type, model	Base plus additionalContext, initialUserMessage, sessionTitle, watchPaths, reloadSkills
classic.Setup	Documented	SetupHookInput: hook_event_name, trigger	Base plus additionalContext
classic.StopFailure	Documented	StopFailureHookInput: hook_event_name, error, error_details, last_assistant_message	Base
classic.Stop	Documented	StopHookInput: includes stop_hook_active, last_assistant_message	Base plus additionalContext
classic.SubagentStart	Documented	SubagentStartHookInput: hook_event_name, agent_id, agent_type	Base plus additionalContext
classic.SubagentStop	Documented	SubagentStopHookInput: includes agent_id, agent_type, last_assistant_message	Base plus additionalContext
classic.TaskCompleted	Documented	TaskCompletedHookInput: hook_event_name, task_id, task_subject, task_description, teammate_name, team_name	Base
classic.TaskCreated	Documented	TaskCreatedHookInput: same fields as TaskCompleted	Base
classic.TeammateIdle	Documented	TeammateIdleHookInput: hook_event_name, teammate_name, team_name	Base
classic.UserPromptExpansion	Documented	UserPromptExpansionHookInput: includes expansion_type, command_name, command_args, prompt	Base plus additionalContext, suppressOriginalPrompt
classic.UserPromptSubmit	Documented	UserPromptSubmitHookInput: includes prompt, source, session_title	Base plus additionalContext, sessionTitle, suppressOriginalPrompt
classic.WorktreeCreate	Documented	WorktreeCreateHookInput: hook_event_name, name	Base plus worktreePath
classic.WorktreeRemove	Documented	WorktreeRemoveHookInput: hook_event_name, worktree_path	Base

In this table, "Base" means block, preventContinuation, and stopReason.

Related Pages

• Mod API Overview
• Hooks and the Hook Chain
• Classic Event Types (the full input and result types)
• Hook Events