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Modern automation pattern: Set conditions directly on assets rather than creating separate schedules or sensors. The system evaluates conditions every 30 seconds and launches runs when conditions are met.

Benefits:

• Asset-native: No separate job definitions needed
• Dependency-aware: Automatically considers upstream state
• Composable: Build complex conditions from simple building blocks
• Declarative: Easier to reason about than imperative sensors

Basic examples: See the main SKILL.md Quick Reference for eager(), on_cron(), and on_missing() examples.

Requirements

• Assets only: Declarative automation does not work with ops or graphs
• Sensor must be enabled: The default_automation_condition_sensor must be toggled on in the Dagster UI under Automation → Sensors

Core Concepts

The Three Main Conditions

Start with one of these three conditions rather than building conditions from scratch:

• eager(): Execute immediately when dependencies update
• on_cron(): Execute on a schedule after dependencies update
• on_missing(): Execute missing partitions when dependencies are ready

Customization

All three main conditions can be customized:

• Remove sub-conditions with .without()
• Replace sub-conditions with .replace()
• Filter dependencies with .allow() and .ignore()
• Combine with boolean operators: & (AND), | (OR), ~ (NOT)

Advanced Concepts

• Status vs Events: Conditions can be persistent states or transient moments
• Operands: Base building blocks like missing(), newly_updated()
• Operators: Tools for composition like since(), any_deps_match()

Reference Files Index

• Advanced — status vs events, run grouping, or filtering in declarative automation
• Core Concepts — using eager(), on_cron(), or on_missing() conditions
• Customization — customizing conditions with without(), replace(), allow(), or ignore()
• Operands — base condition building blocks like missing() or newly_updated()
• Operators — combining conditions using since, any_deps_match, or boolean operators