Event Modeling and .em.hcl
Choose a path that matches what you already know.
Discover the business story first
Describe how people do the work without software. Identify who acts, what starts each action, and what information they need.
- Set the scope with a domain expert. List human roles, system actors, and permission boundaries.
- Brainstorm past-tense business Events. Plot their causes, alternatives, and outcomes in business time.
- Sketch Screens around user decisions. Add Commands and their issuers, then design automation todo lists and external translations.
- Define Read Models from consumer questions. Trace their fields to Events and identify ownership boundaries.
- Write scenarios for rules and failures. Review field completeness and business meaning separately from HCL validity.
- Make each pattern-sized capability an explicit workflow. Record decisions and unresolved questions where they belong.
These six groups summarize the process, not six mandatory canvas steps. Continue at the first incomplete step in an existing model.
The Event Modeling methodology covers discovery, facilitation, review, and governance. The v0.4.0 specification defines legal HCL.
Map of the cheat sheet
5 elements · 4 patterns · 6 workshop stages · 4 smells
Event, Command, Read Model, Screen, Processor.
4PatternsState Change, State View, Automation, Translation.
From Events to scenarios.
Bed, left chair, right chair, shelf.
The pages
Elements
The five things shown on an Event Model.
Open → 02Patterns
Four shapes for organizing a workflow.
Open → 03Scenarios
Pattern-specific Given, When, and Then rules.
Open → 04Language
Blocks, references, fields, and canonical flow.
Open → 05Quality
Errors, warnings, and four modeling smells.
Open → MoreFull learning guide
Exercises, facilitation notes, and a capstone.
Open on GitHub →