Classic Result, Config, and Elicitation Types

Types with Fields

Each type below has its own table of fields.

BackgroundTaskSummary

Field	Status	What it is for	Type and limits
id	Documented: An official docs page names this item.	The ID of the background task.	Type: string.
type	Documented: An official docs page names this item.	Friendly task-type label (for example 'shell', 'subagent', 'monitor', 'workflow'). It falls back to the raw discriminant for unknown types.	Type: string.
status	Documented: An official docs page names this item.	The status of the background task.	Type: string.
description	Documented: An official docs page names this item.	Free-text description. Capped at 1000 chars. Clipped values append an in-string "... [+N chars]" marker.	Type: string.
command	Documented: An official docs page names this item.	Shell command line. Only present for 'shell' tasks. Capped at 1000 chars with the same "... [+N chars]" marker.	Type: string. Optional.
agent_type	Documented: An official docs page names this item.	Subagent type name. Only present for 'subagent' tasks.	Type: string. Optional.
server	Documented: An official docs page names this item.	MCP server name. Only present for 'monitor' / 'MCP task' tasks.	Type: string. Optional.
tool	Documented: An official docs page names this item.	MCP tool name. Only present for 'monitor' / 'MCP task' tasks.	Type: string. Optional.
name	Documented: An official docs page names this item.	Workflow name. Only present for 'workflow' tasks.	Type: string. Optional.

BaseHookInput

Field	Status	What it is for	Type and limits
session_id	Documented: An official docs page names this item.	The ID of the current session.	Type: string.
transcript_path	Documented: An official docs page names this item.	Path to the conversation JSONL file. See Transcript Format.	Type: string.
cwd	Documented: An official docs page names this item.	The working directory when the hook fires.	Type: string.
prompt_id	Documented: An official docs page names this item.	A UUID that ties a user prompt to all later events until the next prompt. It is also the prompt.id attribute on OpenTelemetry events. Absent until the first user input.	Type: string. Optional.
permission_mode	Documented: An official docs page names this item.	The permission mode in force, such as default, plan, or acceptEdits. See Input and Output.	Type: string. Optional.
agent_id	Documented: An official docs page names this item.	Subagent identifier. Present only when the hook fires inside a subagent. Absent on the main thread. Use it, not agent_type, to tell subagent calls apart.	Type: string. Optional.
agent_type	Documented: An official docs page names this item.	Agent type name, such as general-purpose. Present inside a subagent, or on the main thread of a session started with --agent.	Type: string. Optional.
effort	Documented: An official docs page names this item.	Reasoning effort of the current turn. Present for hooks in a tool-use context on a model that supports effort. Absent for session-lifecycle hooks.	Type: object. Optional.

ClassicEventOf

The classic (settings) hook events, one for each classic event name. e is the whole stdin input of the hook, with the base fields (transcript_path, cwd) included. Object. One key for each classic event. The chain is managed settings hooks, then hooks modules, then the other settings hooks. A managed block ends it above every module.

Field	Status	What it is for	Type and limits
[E in ClassicHookEvent as `classic.${E}`]	Documented: An official docs page names this item.	The input of each classic.* event: the tool-call envelope for classic.PreToolUse, the hook input for the rest.	Type: E extends 'PreToolUse' ? ToolCallEnvelope : ClassicHookInputs[E].

ClassicResult

Everything that the answer of a classic hook event can carry, named as the JSON output of the classic hook names it. Each event reads its subset (ClassicResultOf). The settings hooks fold into one of these. A field of the wrong shape fails the hook.

Field	Status	What it is for	Type and limits
block	Documented: An official docs page names this item.	decision: "block" with this text as reason (a command hook's exit code 2): the block, veto or re-prompt of the event.	Type: string. Optional.
preventContinuation	Documented: An official docs page names this item.	continue: false: the session stops after this event.	Type: true. Optional.
stopReason	Documented: An official docs page names this item.	Displayed when preventContinuation stops the session (stopReason).	Type: string. Optional.
additionalContext	Documented: An official docs page names this item.	hookSpecificOutput.additionalContext, one entry for each hook: text handed to the model with the event.	Type: string[]. Optional.
sessionTitle	Documented: An official docs page names this item.	hookSpecificOutput.sessionTitle (UserPromptSubmit, SessionStart).	Type: string. Optional.
suppressOriginalPrompt	Documented: An official docs page names this item.	hookSpecificOutput.suppressOriginalPrompt (UserPromptSubmit, UserPromptExpansion).	Type: true. Optional.
initialUserMessage	Documented: An official docs page names this item.	hookSpecificOutput.initialUserMessage (SessionStart).	Type: string. Optional.
watchPaths	Documented: An official docs page names this item.	hookSpecificOutput.watchPaths (SessionStart).	Type: string[]. Optional.
reloadSkills	Documented: An official docs page names this item.	hookSpecificOutput.reloadSkills (SessionStart).	Type: true. Optional.
permissionDecision	Documented: An official docs page names this item.	hookSpecificOutput.permissionDecision (PreModelSwitch).	Type: 'allow' | 'deny' | 'ask'. Optional.
permissionDecisionReason	Documented: An official docs page names this item.	hookSpecificOutput.permissionDecisionReason (PreModelSwitch).	Type: string. Optional.
decision	Documented: An official docs page names this item.	hookSpecificOutput.decision (PermissionRequest).	Type: PermissionRequestDecision. Optional.
updatedToolOutput	Documented: An official docs page names this item.	hookSpecificOutput.updatedToolOutput (PostToolUse): replaces what the model sees of the result of the tool.	Type: unknown. Optional.
updatedMCPToolOutput	Documented: An official docs page names this item.	hookSpecificOutput.updatedMCPToolOutput (PostToolUse, MCP tools only).	Type: unknown. Optional.
retry	Documented: An official docs page names this item.	hookSpecificOutput.retry (PermissionDenied).	Type: true. Optional.
displayContent	Documented: An official docs page names this item.	hookSpecificOutput.displayContent (MessageDisplay).	Type: string. Optional.
worktreePath	Documented: An official docs page names this item.	hookSpecificOutput.worktreePath (WorktreeCreate, a command hook prints it): the worktree that the hook created, absolute or relative to its cwd.	Type: string. Optional. If unset, the session creates its git worktree as it would unhooked.

ClassicResultFields

The event-specific fields of ClassicResult that each classic event reads (its hookSpecificOutput), by event. An event absent here reads none of them. Every event has block, preventContinuation and stopReason.

Field	Status	What it is for	Type and limits
UserPromptSubmit	Documented: An official docs page names this item.	The result fields of classic.UserPromptSubmit, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext' | 'sessionTitle' | 'suppressOriginalPrompt'.
UserPromptExpansion	Documented: An official docs page names this item.	The result fields of classic.UserPromptExpansion, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext' | 'suppressOriginalPrompt'.
SessionStart	Documented: An official docs page names this item.	The result fields of classic.SessionStart, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext' | 'initialUserMessage' | 'sessionTitle' | 'watchPaths' | 'reloadSkills'.
Setup	Documented: An official docs page names this item.	The result fields of classic.Setup, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
PreModelSwitch	Documented: An official docs page names this item.	The result fields of classic.PreModelSwitch, besides the block, preventContinuation, and stopReason that every event has.	Type: 'permissionDecision' | 'permissionDecisionReason'.
PostModelSwitch	Documented: An official docs page names this item.	The result fields of classic.PostModelSwitch, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
SubagentStart	Documented: An official docs page names this item.	The result fields of classic.SubagentStart, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
PostToolUse	Documented: An official docs page names this item.	The result fields of classic.PostToolUse, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext' | 'updatedToolOutput' | 'updatedMCPToolOutput'.
PostToolUseFailure	Documented: An official docs page names this item.	The result fields of classic.PostToolUseFailure, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
PostToolBatch	Documented: An official docs page names this item.	The result fields of classic.PostToolBatch, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
Stop	Documented: An official docs page names this item.	The result fields of classic.Stop, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
SubagentStop	Documented: An official docs page names this item.	The result fields of classic.SubagentStop, besides the block, preventContinuation, and stopReason that every event has.	Type: 'additionalContext'.
PermissionDenied	Documented: An official docs page names this item.	The result fields of classic.PermissionDenied, besides the block, preventContinuation, and stopReason that every event has.	Type: 'retry'.
PermissionRequest	Documented: An official docs page names this item.	The result fields of classic.PermissionRequest, besides the block, preventContinuation, and stopReason that every event has.	Type: 'decision'.
MessageDisplay	Documented: An official docs page names this item.	The result fields of classic.MessageDisplay, besides the block, preventContinuation, and stopReason that every event has.	Type: 'displayContent'.
WorktreeCreate	Documented: An official docs page names this item.	The result fields of classic.WorktreeCreate, besides the block, preventContinuation, and stopReason that every event has.	Type: 'worktreePath'.

ClassicResultOf

What the hook of each classic hook event returns and its next(e) resolves to: the own subset of ClassicResult for the event. [E in ClassicHookEvent as classic.${E}] ``. classic.PreToolUse keeps its allow / ask / deny result (PreToolUseResult).

Field	Status	What it is for	Type and limits
[E in ClassicHookEvent as `classic.${E}`]	Documented: An official docs page names this item.	The result of each classic.* event: PreToolUseResult for classic.PreToolUse, a pick of ClassicResult fields for the rest.	Type: E extends 'PreToolUse' ? PreToolUseResult : Pick<ClassicResult, 'block' | 'preventContinuation' | 'stopReason' | (E extends keyof ClassicResultFields ? ClassicResultFields[E] : never)>.

ConfigChangeHookInput

Combines ConfigChangeHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always ConfigChange.	Type: 'ConfigChange'.
source	Documented: An official docs page names this item.	Which settings source changed.	Type: 'user_settings' | 'project_settings' | 'local_settings' | 'policy_settings' | 'skills'.
file_path	Documented: An official docs page names this item.	The settings file that changed.	Type: string. Optional.

CwdChangedHookInput

Combines CwdChangedHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always CwdChanged.	Type: 'CwdChanged'.
old_cwd	Documented: An official docs page names this item.	The working directory before the change.	Type: string.
new_cwd	Documented: An official docs page names this item.	The working directory after the change.	Type: string.

DirectoryAddedHookInput

Combines DirectoryAddedHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always DirectoryAdded.	Type: 'DirectoryAdded'.
directory	Documented: An official docs page names this item.	Absolute path of the directory that was added.	Type: string.
source	Documented: An official docs page names this item.	How the directory was added: "slash_command" for /add-dir, "register_repo_root" for the SDK control_request.	Type: 'slash_command' | 'register_repo_root'.

ElicitationHookInput

Hook input for the Elicitation event. Fired when an MCP server requests user input. Hooks can auto-respond (accept/decline) instead of displaying the dialog. Combines ElicitationHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always Elicitation.	Type: 'Elicitation'.
mcp_server_name	Documented: An official docs page names this item.	The name of the MCP server that asks for input.	Type: string.
message	Documented: An official docs page names this item.	The text that the MCP server displays to ask for input.	Type: string.
mode	Documented: An official docs page names this item.	Whether the MCP server asks with a form or with a url.	Type: 'form' | 'url'. Optional.
url	Documented: An official docs page names this item.	The URL to open, in url mode.	Type: string. Optional.
elicitation_id	Documented: An official docs page names this item.	The ID of the request.	Type: string. Optional.
requested_schema	Documented: An official docs page names this item.	The schema of the form the server asks for, in form mode.	Type: Record<string, unknown>. Optional.

ElicitationResultHookInput

Hook input for the ElicitationResult event. Fired after the user responds to an MCP elicitation. Hooks can observe or override the response before the engine sends it to the server. Combines ElicitationResultHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always ElicitationResult.	Type: 'ElicitationResult'.
mcp_server_name	Documented: An official docs page names this item.	The name of the MCP server that asked.	Type: string.
elicitation_id	Documented: An official docs page names this item.	The ID of the request.	Type: string. Optional.
mode	Documented: An official docs page names this item.	Whether the server asked with a form or with a url.	Type: 'form' | 'url'. Optional.
action	Documented: An official docs page names this item.	The answer: accept, decline, or cancel.	Type: 'accept' | 'decline' | 'cancel'.
content	Documented: An official docs page names this item.	The values submitted with the answer.	Type: Record<string, unknown>. Optional.

FileChangedHookInput

Combines FileChangedHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always FileChanged.	Type: 'FileChanged'.
file_path	Documented: An official docs page names this item.	The path of the file that changed.	Type: string.
event	Documented: An official docs page names this item.	What happened to the file: change, add, or unlink.	Type: 'change' | 'add' | 'unlink'.

InstructionsLoadedHookInput

Combines InstructionsLoadedHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always InstructionsLoaded.	Type: 'InstructionsLoaded'.
file_path	Documented: An official docs page names this item.	The path of the instructions file that was loaded.	Type: string.
memory_type	Documented: An official docs page names this item.	The kind of memory file: User, Project, Local, or Managed.	Type: 'User' | 'Project' | 'Local' | 'Managed'.
load_reason	Documented: An official docs page names this item.	Why the file was loaded. This is the matcher.	Type: 'session_start' | 'nested_traversal' | 'path_glob_match' | 'include' | 'compact'.
globs	Documented: An official docs page names this item.	The path globs from the paths: frontmatter of the file.	Type: string[]. Optional. Present only when load_reason is path_glob_match (InstructionsLoaded input).
trigger_file_path	Documented: An official docs page names this item.	The file whose access caused the load.	Type: string. Optional.
parent_file_path	Documented: An official docs page names this item.	The file that includes this one.	Type: string. Optional.

MessageDisplayHookInput

Hook input for the MessageDisplay event. Fired with each batch of newly completed lines while an assistant message streams. Display-only: the stored message and what the model sees are untouched. Combines MessageDisplayHookInput, BaseHookInput.

Field	Status	What it is for	Type and limits
hook_event_name	Documented: An official docs page names this item.	The event name: always MessageDisplay.	Type: 'MessageDisplay'.
turn_id	Documented: An official docs page names this item.	UUID of the current turn.	Type: string.
message_id	Documented: An official docs page names this item.	UUID of the assistant message being displayed. Stable across every flush of the same message. Not the API msg_... id.	Type: string.
index	Documented: An official docs page names this item.	Zero-based index of this delta within the message. Increments by one for each flush.	Type: number.
final	Documented: An official docs page names this item.	True on the last flush of the message. Exactly one flush for each message has it.	Type: boolean.
delta	Documented: An official docs page names this item.	The newly completed lines since the last flush. Always whole lines, except on the final flush. Treat final as the end-of-message signal.	Type: string.

Related Pages

• Classic Event Types
• Mod API Types