smithy-hono

A Smithy build plugin that generates Hono routes, Zod validation schemas, typed error classes, and SSE event types from a Smithy model — plus a set of runtime-agnostic npm packages (security pipeline, persistence/DataStore, deployment adapters, MCP bridge) that the generated code wires into.

What it does

Given a Smithy model annotated with @http traits, the codegen plugin emits:

• generated/*.gen.ts per resource — Zod schemas, typed error classes, an operation handler interface, and a createXyzRouter(ops, middleware?) factory.
• generated/events.gen.ts — a discriminated union of all @sseEvent shapes, a <Service>EventEmitter interface, and a typed event-source client.
• generated/registry.gen.ts — the OPERATIONS metadata map (auth schemes, permissions, cost, sensitive fields, streaming) the security pipeline reads.
• a typed client and, for @persisted resources, zero-handler DB-backed CRUD.

Your implementation files (src/routes/*.ts) satisfy the generated interfaces — they are never overwritten.

The package set

The codegen output runs against a set of runtime-agnostic @smithy-hono/* npm packages (Web-standard APIs only — Workers / Lambda / Node):

Package	What it provides
@smithy-hono/security-core	Pre-deserialization security pipeline: OIDC cookie sessions, SH-HMAC S2S signing, CSRF, CORS, security headers, rate limiting, two-tier authorization, audit.
@smithy-hono/data-core	The DataStore<T> persistence port + in-memory dev store + conformance suite — backs @persisted CRUD.
@smithy-hono/adapter-node	Node/Redis adapter for the security-core storage interfaces.
@smithy-hono/adapter-cf	Cloudflare (Workers KV + Durable Objects) adapter.
@smithy-hono/adapter-aws	AWS (DynamoDB + Secrets Manager) adapter.
@smithy-hono/adapter-postgres	Postgres-backed DataStore<T> (durable store of record for Node).
@smithy-hono/mcp-core	Bridge exposing a generated service as an MCP server over Streamable-HTTP JSON-RPC (resources + prompts).
@smithy-hono/test-kit	Consumer testing toolkit (devDependency): drive the generated typed client against your pipeline in-process.

@smithy-hono/key-tool (S2S signing-key lifecycle library + CLI) ships in the repo but is not published — it is a dev/ops tool.

How it fits together

model/*.smithy
  │
  ▼ ./gradlew smithyBuild
generated/*.gen.ts   (never edit)
  │
  ▼ implement the interfaces
src/routes/*.ts      (you own these)
  │
  ▼ tsup
dist/                (deployable bundle)

Where to go next

• New here? Start with the Getting started quickstart.
• Building a service? The Consuming & building section is the end-to-end guide: install & wire the artifacts, author your model, consume the generated code, secure it, and deploy it.
• Securing it? Security covers the pipeline, config, OIDC sessions, S2S HMAC, and the production checklist.
• Deploying it? Deployment is the platform matrix (Node/k8s, Cloudflare Workers, AWS Lambda).
• Extending the plugin? The Codegen plugin guide documents the emitter design and trait authoring.
• Operating it? The Operational guides cover publishing, testing, key lifecycle, and CI pipeline testing.
• Looking something up? The Reference section has the auth design and curated indexes of the in-repo packages, deploy targets, and examples.