TaskCreated

Runs when a task is being created via the TaskCreate tool. Use this to enforce naming conventions, require task descriptions, or prevent certain tasks from being created. In a session without the Task tools, this event doesn't fire.

TaskCreated hooks don't support matchers and fire on every occurrence.

TaskCreated input

In addition to the common input fields, TaskCreated hooks receive task_id, task_subject, and optionally task_description, teammate_name, and team_name.

{
  "session_id": "abc123",
  "transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl",
  "cwd": "/Users/...",
  "hook_event_name": "TaskCreated",
  "task_id": "task-001",
  "task_subject": "Implement user authentication",
  "task_description": "Add login and signup endpoints",
  "teammate_name": "implementer",
  "team_name": "session-a1b2c3d4"
}

Field	Description
task_id	Identifier of the task being created
task_subject	Title of the task
task_description	Detailed description of the task. May be absent
teammate_name	Name of the teammate creating the task. May be absent
team_name	Deprecated. Session-derived team name; will be removed in a future release

TaskCreated decision control

A TaskCreated hook can block the creation in two ways. Either way, Claude Code deletes the task and returns your message to Claude as the tool's error. Claude Code ignores continue: false from this event and Claude keeps working.

• Exit code 2: Claude Code returns the stderr text as the message.
• JSON \{"decision": "block", "reason": "..."\}: Claude Code returns reason as the message.

This example blocks tasks whose subjects don't follow the required format:

#!/bin/bash
INPUT=$(cat)
TASK_SUBJECT=$(echo "$INPUT" | jq -r '.task_subject')

if [[ ! "$TASK_SUBJECT" =~ ^\[TICKET-[0-9]+\] ]]; then
  echo "Task subject must start with a ticket number, e.g. '[TICKET-123] Add feature'" >&2
  exit 2
fi

exit 0