AI Agent Hooks

AI agent hooks are lifecycle events triggered by state changes in an agent system. When specific things happen—an agent starts, a command is issued, the gateway boots—hooks fire and execute configured actions. This enables agents to manage themselves and respond to system events automatically.

Think of hooks like event handlers in software development, but for agent lifecycles:

Event: agent_session_start
Hook: Read memory files, check for pending tasks

Event: command_issued  
Hook: Log the command, validate permissions

Event: gateway_boot
Hook: Initialize connections, restore state

Hooks transform agents from passive responders into self-managing systems that react to their environment.

Self-management

Without hooks, agents need external orchestration for setup and teardown. With hooks, agents handle their own lifecycle:

• Initialize context when starting
• Clean up resources when stopping
• Respond to configuration changes
• Handle errors gracefully

Event-driven architecture

Hooks enable event-driven patterns:

• External events trigger agent behavior
• Agents react to system state changes
• Loose coupling between components
• Flexible, composable systems

Consistency

Hooks ensure consistent behavior:

• Every session starts the same way
• Every shutdown follows the same cleanup
• Every error triggers the same handling
• No forgotten initialization steps

Extensibility

Hooks let you extend agent behavior without modifying core code:

• Add logging to all events
• Inject validation checks
• Trigger notifications
• Connect to external systems

Session hooks

Triggered by agent session lifecycle:

hooks:
  session_start:
    - load_memory_files
    - check_pending_tasks
    - initialize_tool_connections
    
  session_end:
    - save_working_memory
    - update_daily_log
    - release_resources
    
  session_error:
    - log_error_details
    - notify_operator
    - attempt_recovery

Command hooks

Triggered by agent actions:

hooks:
  pre_command:
    - validate_permissions
    - log_command_attempt
    
  post_command:
    - log_command_result
    - update_audit_trail
    
  command_error:
    - capture_error_context
    - suggest_alternatives

System hooks

Triggered by infrastructure events:

hooks:
  gateway_boot:
    - restore_agent_states
    - initialize_channels
    - start_heartbeat_scheduler
    
  gateway_shutdown:
    - graceful_agent_termination
    - save_system_state
    - close_connections
    
  config_change:
    - reload_affected_agents
    - validate_new_config

Integration hooks

Triggered by external system events:

hooks:
  webhook_received:
    - validate_webhook_signature
    - route_to_appropriate_agent
    
  message_received:
    - check_rate_limits
    - apply_content_filters
    
  tool_response:
    - validate_tool_output
    - transform_for_agent

Configuration-based hooks

Define hooks in configuration files:

# hooks.yaml
hooks:
  session_start:
    - action: read_files
      files:
        - SOUL.md
        - USER.md
        - MEMORY.md
        - "memory/{{today}}.md"
    
    - action: execute
      command: "check_notifications"
      
    - action: notify
      condition: "pending_tasks > 0"
      message: "You have {{pending_tasks}} pending tasks"

Code-based hooks

Register hooks programmatically:

from agent_framework import Agent, hooks

agent = Agent("assistant")

@hooks.on("session_start")
def initialize_session(session):
    session.load_memory()
    session.check_pending_tasks()
    session.log("Session started")

@hooks.on("session_end")
def cleanup_session(session):
    session.save_working_memory()
    session.update_daily_log()
    session.log("Session ended")

@hooks.on("error")
def handle_error(session, error):
    session.log_error(error)
    session.notify_operator(error)

Declarative hooks in agent files

Some systems define hooks within agent configuration:

# AGENTS.md

On Session Start

1. Read SOUL.md for identity
2. Read USER.md for user context
3. Read recent memory files
4. Check HEARTBEAT.md for pending items

On Session End

1. Update daily log with session summary
2. Save any explicit memories
3. Record session metrics

The initialization chain

Multiple hooks execute in sequence at startup:

session_start:
  1. validate_environment    → Check prerequisites
  2. load_identity          → Read SOUL.md
  3. load_context           → Read memory files  
  4. initialize_tools       → Connect to services
  5. check_pending          → Review outstanding items
  6. ready_notification     → Signal ready state

Each step depends on previous steps completing successfully.

The guard pattern

Pre-hooks validate before action proceeds:

pre_command:
  - check: rate_limit_ok
    on_fail: return_rate_limited
    
  - check: permission_valid
    on_fail: return_unauthorized
    
  - check: input_sanitized
    on_fail: return_invalid_input
    
  # Only if all guards pass:
  → execute_command

The observer pattern

Hooks observe without modifying behavior:

post_command:
  - log_to_audit_trail
  - update_metrics
  - trigger_analytics
  
# Command completes normally; hooks just observe

The recovery pattern

Error hooks attempt recovery:

on_error:
  1. log_error_details
  2. attempt_retry (up to 3 times)
  3. if retry_failed:
       - notify_operator
       - enter_safe_mode
  4. if recoverable:
       - apply_fix
       - resume_operation

Production agent frameworks like Clawdbot/OpenClaw use hooks extensively:

Gateway boot hooks

gateway_boot:
  - Initialize logging
  - Load configuration
  - Restore agent states from persistence
  - Start channel listeners
  - Begin heartbeat scheduler
  - Signal ready

Agent session hooks

session_start:
  - Read workspace context (AGENTS.md)
  - Load identity (SOUL.md) 
  - Load user context (USER.md)
  - Load memory (MEMORY.md, daily logs)
  - Check for bootstrap (BOOTSTRAP.md)

Message handling hooks

message_received:
  - Validate source
  - Apply rate limiting
  - Check content filters
  - Route to appropriate session
  - Log interaction

Keep hooks focused

Each hook should do one thing:

# Good
hooks:
  session_start:
    - load_memory
    - check_tasks
    - init_tools

# Bad
hooks:
  session_start:
    - do_all_initialization  # Too broad

Handle errors in hooks

Hooks that fail shouldn't crash the system:

@hooks.on("session_start")
def load_memory(session):
    try:
        session.load_memory_files()
    except FileNotFoundError:
        session.log("Memory files not found, starting fresh")
        # Continue without crashing

Order matters

Hooks often have dependencies:

session_start:
  - load_identity      # Must be first
  - load_memory        # Depends on identity
  - check_permissions  # Depends on both

Document and enforce ordering requirements.

Async when possible

Independent hooks can run concurrently:

session_start:
  parallel:
    - load_memory_files
    - check_external_services
    - fetch_notifications
  then:
    - synthesize_context

Test hooks independently

Hooks should be testable in isolation:

def test_session_start_hook():
    mock_session = MockSession()
    hooks.session_start(mock_session)
    assert mock_session.memory_loaded
    assert mock_session.identity_set

All three create automated agent behavior, but differ:

Use hooks for events, cron for schedules, heartbeats for awareness.