onion-lasagna-architect

Onion Lasagna Architect

Overview

Design Onion Lasagna systems by deciding bounded contexts, adapters, schema libraries, server framework, client packages, read models, and workflows before code is written.

Procedure

1. Inspect existing project shape when present.
2. Identify business capabilities and split bounded contexts by ownership of invariants.
3. Choose presentation surfaces: HTTP, GraphQL, events, or a mix.
4. Choose concrete Onion Lasagna packages for schema, server, client, and workflow needs.
5. Identify read models separately from write/domain models.
6. Identify operations that need saga workflows.
7. Produce an implementation order ending with review.

Package Chooser

Name concrete packages when the target stack is known:

• Core: @cosmneo/onion-lasagna.
• HTTP routes: @cosmneo/onion-lasagna/http/route, @cosmneo/onion-lasagna/http/server.
• Server adapters: @cosmneo/onion-lasagna-hono, @cosmneo/onion-lasagna-fastify, @cosmneo/onion-lasagna-express, @cosmneo/onion-lasagna-elysia, @cosmneo/onion-lasagna-nestjs.
• GraphQL: @cosmneo/onion-lasagna/graphql, @cosmneo/onion-lasagna-yoga.
• Events: @cosmneo/onion-lasagna/events, @cosmneo/onion-lasagna/events/handler, @cosmneo/onion-lasagna/events/server, @cosmneo/onion-lasagna/events/shared, @cosmneo/onion-lasagna/events/asyncapi.
• Schemas: @cosmneo/onion-lasagna-zod, @cosmneo/onion-lasagna-typebox, @cosmneo/onion-lasagna-valibot, @cosmneo/onion-lasagna-arktype.
• Clients: @cosmneo/onion-lasagna-client, @cosmneo/onion-lasagna-axios, @cosmneo/onion-lasagna-react-query, @cosmneo/onion-lasagna-graphql-client.
• Workflows: @cosmneo/onion-lasagna-saga.

Output

Return:

• bounded context map;
• package choices with concrete @cosmneo/* names where known;
• data flow;
• error flow;
• read/write/workflow boundaries;
• saga candidates;
• test strategy;
• implementation order.

Use ../../references/omninode-patterns.md for the preferred structure and ../../references/package-entrypoints.md for package choices. Use ../../references/architecture-rules.md for error-boundary rules. Verify target exports before importing. Known domain and app errors pass through; unknown infrastructure failures are wrapped as InfraError or a specific subclass; presentation maps coded errors to client responses and masks internal failures.