create-event-model

Create Event Model

Seed a project with a working Event Model: a markdown file wrapping the canonical hotel-booking DSL, plus a model-viewer.html page that renders it (and lists any companion slice specs in a sidebar).

Input

The argument $ARGUMENTS is the target path for the model file. If no argument is provided, default to blueprint_dsl.md in the project root. If the argument doesn't already end in .md, append .md.

What to do

1. Locate the template files. Use the Bash tool with dirname on the path to this SKILL.md to find the skill directory — do not hard-code an absolute path. The two templates are:

   • template.md — markdown wrapper containing the canonical DSL inside a fenced mermaid block. Has a {{MODEL_NAME}} placeholder in the title.
   • template.html — the model-viewer.html page (markdown + diagram + slice-spec sidebar). Also has a {{MODEL_NAME}} placeholder for the default model the viewer loads.

2. Determine the two output paths:

   • Model output: the $ARGUMENTS path (or blueprint_dsl.md if absent), with .md appended if missing.
   • Viewer output: a sibling of the model output, always named model-viewer.html.

3. Compute the model basename: the model output filename without its .md extension. This is the {{MODEL_NAME}} substitution value (e.g. blueprint_dsl.md → blueprint_dsl).

4. Write template.md to the model output, substituting {{MODEL_NAME}} with the basename. Preserve tab indentation in the embedded DSL exactly — the parser is indent-aware and uses tabs.

5. Write template.html to the viewer output, substituting {{MODEL_NAME}} with the same basename so the viewer loads the correct model by default.

6. If either output file already exists, confirm with the user before overwriting (per file).

7. Confirm to the user what you wrote and where, plus the command to view it:

   python3 -m http.server 8000
   # then open http://localhost:8000/model-viewer.html
   

   The viewer accepts ?model=<basename> to load a different model in the same directory. The slice-spec sidebar fills in once the user runs /mermaid-event-model:spec-slices against the model.

What the templates contain

template.md

A markdown file wrapping the canonical hotel-booking event model in a fenced mermaid block. The DSL itself exercises every feature:

• Actors: Manager, Guest
• Aggregates: Inventory, Auth, Payment, GPS
• UIs with data sections: Registration, Room Management, Booking, Maintenance, Check-in, Payment, Sales Report
• Commands with data sections: Register, Add Room, Book Room, Ready Room, Check-in, Checked Out, Pay, Process Payment, and a fieldless hotelProximityTranslator
• Domain events with data sections: Registered, Room Added, Room Booked, Room Readied, Checked In, Position Updated, Guest Left Hotel, Checked Out, Payment Requested, Payment Succeeded
• External events with data sections: Gateway Confirmed (a payment-gateway webhook that feeds into processPayment)
• Read models with data sections: Room Availability, Cleaning Schedule, Guest Roster, Payments to Process, Sales Report
• Automations: Check-out Automation (Manager), Payment Processor (Guest)
• Slices covering every edge in the model (16 slices total), demonstrating both command slices (ui/automation → command → event) and read slices (event → readModel → ui/automation)
• A cycle: paymentSucceeded ↔ paymentsToProcess — exercises the renderer's back-edge handling

template.html

A model-viewer.html page that:

• Renders the model .md (markdown prose around the embedded eventModel diagram) in the main pane
• Lists every spec under <model>-slices/ in a sidebar, falling back to "(no slice specs found)" until the user runs spec-slices
• Polls the active file every 1.5 seconds and re-renders on changes (live reload)
• Loads d3, mermaid, marked, and the @howarddierking/mermaid-event-model package via jsDelivr through a browser importmap, so it works with no install or build step beyond a static file server

Important

• Do NOT modify the template files themselves; this skill only copies them to the target with placeholder substitution.
• Confirm overwrites file-by-file — the user may want to keep one and replace the other.