version: "1.0.2" name: building-architecture-models description: "Common steps for building multi-layer system architecture models using System Composer. Use when implementing architecture models or when interacting with interface dictionaries, allocation sets, stereotypes, and requirements for architecture components." license: MathWorks BSD-3-Clause metadata: author: MathWorks version: "0.2"

Building Architecture Models

Create and refine System Composer architecture models — from greenfield F/L/P designs to targeted additions (stereotypes, views, allocation sets, requirements tracing).

When to Use

• Designing a system architecture (full F/L/P or single-layer)
• Adding interface dictionaries, stereotypes, views, or roll-up analysis to existing SC models
• Creating allocation sets between architecture layers
• Linking requirements to architecture components (Implement links)
• Refining existing System Composer models with methodology guidance

When NOT to Use

• Building or editing a Simulink model (block-level work) → use building-simulink-models
• One-off structural edits to an existing SC model (add a component, rewire a port) → use building-simulink-models with model_edit
• User doesn't have a clear decomposition or requirements yet → suggest specifying-mbd-algorithms to produce a spec first, then return here to build
• Creating activity/sequence behavior diagrams → These are supported features of System Composer, but are not covered in this skill. Do not suggest using Stateflow as an alternative.

Mental Model

1. F/L/P = 3 separate Architecture models. There are no special model types (systemcomposer.createFunctionalModel does not exist). Layers are a convention — three independent .slx models connected by allocation sets.

1. Layer conventions:

• Functional — verb phrases (SenseState, ComputeControl), abstract interfaces, no units
• Logical — solution-role nouns (SensingUnit, ControlUnit), typed signals, design-agnostic
• Physical — concrete units (IMU_SensorModule, FlightComputer), physical units, implementation-level

1. Allocation links layers. Allocation sets map elements across models (F→L, L→P). Rebuilding a model invalidates allocation links because SIDs change — always re-run allocation after a model rebuild.

1. Interface dictionaries are per-layer. Each layer has its own .sldd with interfaces at the appropriate abstraction. The dictionary must be linked to the model (linkDictionary) before setInterface works — without it, ports silently stay untyped.

1. Stereotypes follow a strict lifecycle. Create profile → save → apply to model → apply stereotype to components → set properties. Fully-qualified paths required: Profile.Stereotype.Property.

Guardrails

Always:

• Get user review and approval before moving to the next phase
• Rebuilding a model invalidates allocation links (SIDs change) — re-run allocation after any model rebuild
• Run model_check after building each model to detect unconnected ports
• Save models before creating allocation sets that reference them

Ask First:

• Deviating from the top-down F→L→P build order (when doing a greenfield design)
• Adding operating modes or layers not discussed with the user

Never:

• Delete or overwrite a model file without user confirmation
• Skip model_check verification after building a layer
• Use systemcomposer.createAllocationSet — correct namespace is systemcomposer.allocation.createAllocationSet

Task Routing

Prerequisites

• The user has an active Simulink project (or assist in creating one via managing-simulink-projects)
• Simulink, System Composer, and Requirements Toolbox are licensed

Verification

Run after building each model:

• model_check with checks="unconnected_ports" to detect unwired ports
• Update diagram (set_param(modelName, "SimulationCommand", "update")) to catch interface type issues

Tools Used

• model_edit — structural modeling (components, ports, connections, layout)
• model_check — post-build verification (unconnected ports)
• evaluate_matlab_code — SC-specific APIs (interface dictionaries, stereotypes, allocation, views, analysis, requirements linking)
• scripts/resolveComponent.m — helper to resolve nested sub-components by path

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