| name | sunny:architecture |
| description | Apply Sunny Kolattukudy's architecture principles to design, review, or evaluate systems. Use this skill when Sunny asks "how should I structure X", "design a new module for Y", "review this architecture", "should this be a service?", "what's the right project structure for Z", "is this the right pattern?", or any question about system design, module boundaries, project layout, cloud hosting choices, Azure resource naming, Bicep naming, Function App naming, or technology selection in .NET, Blazor, or Azure/AWS. Also trigger when Sunny shares a design and wants an opinionated read, or when code review feedback touches architectural decisions. |
Apply Sunny's architecture principles to design systems, review proposals, and make technology choices — opinionated, grounded in the actual stack.
Step 1: Understand the problem first
Before proposing anything, ask:
- What problem is this solving? (The why shapes the boundary.)
- Who owns this? (If the team boundary doesn't match the system boundary, flag it — but don't use the term "Conway's law".)
- What's the deployment + test independence story? (Can this be deployed and tested without touching everything else?)
If the request is a review of an existing design, read it first, then apply the principles below.
Step 2: Apply the architecture principles
See references/principles.md for the full reference. The non-negotiables:
- Modular monolith first. Extract to services only when scale demands it independently or team ownership requires it. Late is right.
- Feature folders over layer folders.
Features/LicenseSources/ with Pages/, Components/, Services/ inside beats a flat Pages/, Components/, Services/ structure at the root.
- State in services, not components. Singleton services with private state (or
IMemoryCache for larger cases). No Fluxor, no cascading params.
- API interfaces between modules. Direct HTTP API calls between modules/services. Direct DB access only for internal tools and as a last resort. For background work: Azure Storage Queue → Azure Function (single consumer). For fan-out to multiple consumers: Azure Event Grid or Azure Event Hub. No in-process eventing (no MediatR notifications, no domain events dispatched in-process) — queues and event services are simpler, more obvious, and independently observable.
- No repository pattern over EF Core.
IQueryable<TEntity> extension methods that project to IQueryable<TModel>, composed in controllers. No DAL abstraction layer.
- No mediator / Command pattern. No MediatR, no
IRequest/IHandler, no -Command suffix. Direct controller → service calls only.
- No
-Dto suffix. Use Model (e.g. ProviderModel, CredentialSummaryModel).
- NuGet: Microsoft-first. Write it yourself before pulling in a third-party package. Prefer
System.Text.Json, HttpClient, Microsoft.Extensions.*. If a third-party package has a significant feature advantage, offer it as an option with a license check.
Step 3: Output format
Use this structure. Keep it concise — link to docs rather than reproducing them. Use generic Company.App.* names in examples — never real client names.
## Architecture: [Feature / System Name]
### Problem
[One sentence: what this solves and for whom.]
### Recommendation
[Direct recommendation — what to build, how to structure it, where it lives.]
### Solution structure
[Project layout, folder structure, key files.]
### Alternatives considered
1. [Option] — [Why not recommended in one line]
2. [Option] — [Why not recommended in one line]
### Ownership check
[Who owns this? Does the team boundary match? Flag mismatches plainly — no jargon.]
### Deployment & test independence
[How does this get deployed independently? How do you test it in isolation?]
### Docs
- [Relevant Microsoft docs link]
For reviews (not proposals), swap "Recommendation" for "Assessment" and add a "Concerns" section before Alternatives.
Naming conventions
Solution / project naming:
- Structured company:
CompanyName.RepositoryName.ComponentName — e.g. Acme.Portal.Api
- Complex repo name:
CompanyName.AppName.ComponentName — e.g. Acme.App.Api
- Standard components:
Api, Ui, Domain, Core, Functions, Cli, Data.<Schema>
- Tests:
Tests.PreDeployment, Tests.PostDeployment
Project structure (Blazor WASM + API):
Company.App.Api → ASP.NET Core API (Container Apps)
Company.App.Ui → Blazor WASM client
Company.App.Ui.Web → Blazor WASM host (serves the client)
Company.App.Domain → POCOs shared between server and client (no server deps)
Company.App.Core → Shared backend utilities (not sent to client, not a service layer)
Company.App.Data.<Name> → EF Core project, one per database schema
Company.App.Functions → Azure Functions (one app, many functions)
Company.App.Cli → CLI tooling
Tests.PreDeployment → xunit only (runs before deploy)
Tests.PostDeployment → Reqnroll + Playwright E2E (runs after deploy)
No additional class libraries unless producing a distributable package (minimizing package surface is the reason, not convenience).
Blazor feature folder structure (inside .Ui):
Features/
FeatureName/
Pages/ → @page components
Components/ → sub-components used by this feature
Services/ → IFeatureService + implementation (HttpClient-based)
Services/ → cross-cutting services (auth, local storage, etc.)
Layout/ → app shell, nav, sidebars
API feature folder structure (inside .Api):
Features/
FeatureName/
FeatureNameController.cs → primary controller
SubResourceController.cs → e.g. PermissionsController alongside RolesController
Services/
IFeatureNameService.cs
FeatureNameService.cs
When a feature has natural sub-resources (e.g. Roles → Permissions), include both controllers in the same feature folder. Don't collapse them into one controller.
Mapping pattern
No AutoMapper, no Mapster. Write it directly:
- Entity → Model: extension method on
IQueryable<TEntity> that projects to IQueryable<TModel> (for EF Core queries), or a static .ToModel() extension for in-memory mapping
- Model → Entity (updates):
CopyFrom(model) method on the entity itself
public static IQueryable<ProviderModel> ProjectToModel(this IQueryable<Provider> query) =>
query.Select(p => new ProviderModel { Id = p.Id, Name = p.Name, ... });
public void CopyFrom(ProviderUpdateModel model)
{
Name = model.Name;
}
Don't suggest unit testing pure mapping methods — there's no business logic to test.
Cloud & hosting defaults
Azure (preferred):
- APIs → Azure Container Apps
- Background / queue processing → Azure Functions (one Function App, many functions)
- Very small APIs → Functions-only is acceptable
- Queues → Azure Storage Queues
- IaC → Bicep
AWS (secondary):
- Queues → SQS
- IaC → Terraform
When recommending hosting, state the reason — scale, cost, team familiarity, or existing infra.
Azure infrastructure naming scale
Use deployed Imagile resources as the strongest convention:
- Resource groups:
imagile-prod, imagile-qa
- App environment resources:
imagile-prod-api, imagile-prod-functions, imagile-prod-ui, imagile-prod-sql, imagile-prod-signalr, imagile-prod-key-vault, imagile-prod-identity, imagile-prod-dashboard, imagile-prod-cae
- Child or related resources keep the parent prefix:
imagile-prod-sql/imagile-prod-metabase, imagile-prod-functions-health, imagile-prod-api-health
- Azure-constrained names collapse separators:
imagileprodstorage
- Shared organization resources use shorter platform names when they are not app-environment specific:
imagile-keyvault, imagile-shared-law, imagilecontainers, imagile-comms, imagile-email, imagile-translator
Treat non-Imagile personal projects as weak evidence only. They can explain an exception, but they do not override the Imagile convention.
Preferred app environment pattern:
<app>-<environment>-<role>
Examples: imagile-prod-functions, imagile-prod-api, imagile-prod-ui, imagile-prod-sql, imagile-prod-key-vault.
Resource group pattern:
<app>-<environment>
Storage accounts and other Azure resources that disallow hyphens:
<app><environment><role>
Example: imagileprodstorage.
Shared organization or platform resources:
<app>-<role>
<app>-shared-<role>
Examples: imagile-keyvault, imagile-shared-law, imagilecontainers.
Role vocabulary:
apifunctionsuisqlsignalrkey-vaultidentitydashboardcaestorageai for Application Insights when the deployed convention already uses itlaw for Log Analytics Workspace when space is tight or the deployed convention uses it
Avoid Azure-type prefixes like func-, rg-, st, kv, or appi for Imagile-style app resources unless integrating into a repo that already consistently uses those prefixes. The Imagile convention reads like the product first, not the Azure catalog first.
Naming scale:
- 5 - Imagile convention: Uses
<app>-<environment>-<role> for app resources, <app>-<environment> for the resource group, deployed role vocabulary, and Azure constraints without changing the mental model. Examples: imagile-prod-functions, imagile-prod-key-vault, imagileprodstorage.
- 4 - Acceptable with a reason: Mostly follows app/environment/role ordering with a small resource-specific deviation for uniqueness, DNS, global scope, or Azure restrictions. Example:
imagile-prod-functions-health.
- 3 - Understandable but not preferred: Clear name, but ordering or vocabulary drifts from Imagile convention. Acceptable for legacy resources, not new Bicep. Examples:
prod-imagile-functions, imagile-prod-func.
- 2 - Azure-prefix style: Uses generic Azure abbreviations or type-first naming without a repo-local reason. Examples:
func-imagile-prod, rg-imagile-prod, stimagileprod.
- 1 - Ambiguous or misleading: Omits app, environment, or role; uses a role that does not match the deployed service; or encodes implementation noise. Examples:
backend, prod-service, function1, centralus-prod-app.
For Azure Functions, prefer one Function App per app/environment named <app>-<environment>-functions; put multiple functions inside it. If a resource has a public DNS name or global uniqueness requirement, preserve the convention as far left as possible and put entropy at the end only when required.
For infra naming reviews, include:
### Infra naming
Score: [1-5]/5
[Direct assessment.]
Recommended names:
- Resource group: `...`
- Function App: `...`
- Storage account: `...`
- App Insights: `...`
Testing stack
Always recommend this stack — don't suggest alternatives unless asked:
- xunit — unit and integration tests (
Tests.PreDeployment)
- Reqnroll + Playwright (.NET) — BDD E2E tests (
Tests.PostDeployment). Feature files describe business scenarios; Step Definitions use Page Model abstraction. Extension methods for common UI interactions (MudBlazor/Telerik).
- Impostor — mocking in unit tests (explicit third-party exception)
Project naming: Tests.PreDeployment (xunit only) and Tests.PostDeployment (Reqnroll + Playwright). Never UnitTests or IntegrationTests as top-level names.
Third-party test packages (xunit, Reqnroll, Playwright, Impostor) are the explicit exception to the Microsoft-first NuGet rule.
Data seeding
Two distinct seeding patterns — always use both.
Reference data seeding (static, idempotent)
For lookup tables, roles, permissions, enum values — data that must exist in every environment.
- Static class
ReferenceDataSeeder in the .Data project
- Seeds in FK-dependency order using
SyncReferenceDataAsync<TEntity, TId>() — idempotent upsert (add new, update changed, delete orphans)
- Entity implements
IReferenceDataEntity<TSelf, TId> and provides its own GetSeedData()
- Invoked via CLI:
seed-reference command — runs locally and in CI/CD pipelines after migrations
Test data seeding (deterministic random)
For local dev and staging environments.
- Bogus (NuGet — explicit third-party exception, no Microsoft equivalent)
DataSeeder.cs orchestrates in dependency order; individual entity seeders (e.g. ProviderSeeder.cs) — one per aggregate root- Fixed seed value for determinism:
new Faker(seed: 12345)
- Invoked via CLI:
seed-test command — runs locally and in pull request / staging pipelines
Company.App.Data.Schema/
Seeding/
DataSeeder.cs
ProviderSeeder.cs
CLI tooling
Every repo includes a CLI project (Company.App.Cli) for dev operations, seeding, migrations, and tooling.
System.CommandLine — command routing (Microsoft-supplied)Spectre.Console — output formatting, prompts, progress (explicit third-party exception)
Structure commands as feature folders matching the domain: Commands/Db/Deploy/, Commands/Storage/Seed/, etc.
Local repo setup
Every new repository should include:
.claude/ — Claude Code skills and context. Add a CLAUDE.md at the repo root with project-specific context (stack, conventions, key file paths).- Git hooks — pre-commit hook for linting/formatting, commit-msg hook for conventional commit format. Wire via
.githooks/ with git config core.hooksPath .githooks in onboarding steps.
Ownership & boundaries
When reviewing or designing any module boundary, ask: does the team that owns this code match the boundary being drawn? Flag when:
- A single team is being asked to own something that crosses a natural domain seam
- A boundary is drawn for technical reasons when the org doesn't reflect it
- Ownership is ambiguous — call it out before designing further
Don't use jargon to describe this — just say plainly who owns what and whether it makes sense.
