Interface Contracts

Interface contracts define the inputs and outputs of a model, allowing it to participate in federated simulations. If you only need a standalone model, you can skip this — it's for connecting multiple models together.

Why Interfaces?

When you build a simulation project (multiple models working together), each model is a black box. The interface contract declares:

• Input ports — Values the model receives from outside (bound to scenario parameters)
• Output ports — Values the model exposes to other models (bound to data collectors or properties)

Adding Ports

In the left panel, the Interface Contract section appears when no archetype is selected. Click + to add input or output ports.

Each port has:

• Name — Identifier used in the simulation graph
• Type — int, float, bool, or str
• Binding — What internal value the port connects to

Input Bindings

Input ports bind to scenario parameters. When another model sends a value to your input port, it sets the corresponding scenario parameter before each step.

Output Bindings

Output ports can bind to:

• Data collectors — Aggregated metrics (e.g., average energy)
• Scenario parameters — Current model settings
• Archetype properties — Per-agent values (e.g., Predator.energy)

Version Tracking

The contract has a version number that increments when ports change. Simulation projects that reference your model will detect when the contract is stale and prompt to refresh.