# OpenSpec Change: enterprise-network-protocol

- **Change ID**: enterprise-network-protocol
- **Package**: `@suaveplan/network-protocol`
- **Category**: universal/network
- **Target path**: `universal/network/network-protocol`
- **Status**: SUPERSEDED-BY-GENESIS-WAVE
- **Date**: 2026-04-24

---

## Summary

Deliver `@suaveplan/network-protocol` on the genesis branch from scratch at enterprise quality. The package provides custom application-level protocol definitions: message framing (length-prefix, delimiter, fixed-length), codec registry (encode/decode for message types), protocol versioning and negotiation, session handshake lifecycle, and flow-control primitives. Genesis adds structured errors via `@suaveplan/error`, Zod schemas for all protocol types, OTel instrumentation, `AbortSignal` on handshake and negotiation, injectable `Clock` for session timing, and property-based tests for codec round-trip invariants.

---

## Current-state audit (genesis)

The package does not exist on genesis yet — this is a fresh build.

---

## Available workspace deps on genesis

| Package | Role |
|---|---|
| `@suaveplan/error` (`workspace:^`) | Base class for `NetworkProtocolError`; stable error codes |
| `@suaveplan/types` (`workspace:^`) | `LoggerLike`, `Clock`, `EventBusLike` |
| `@suaveplan/events` (`workspace:^`) | Event bus for session lifecycle events |
| `@suaveplan/logger` (`workspace:^`) | Structured logging |
| `@suaveplan/serialize` (`workspace:^`) | MessagePack binary serialization |
| `@suaveplan/crypto-utils` (`workspace:^`) | Byte utilities (concat, i2osp, os2ip) for framing |
| `zod` (`catalog:forms`) | Zod schemas |
| `@opentelemetry/api` (`catalog:observability`) | Spans + counters on encode/decode |
| `tslib` (`catalog:build`) | Runtime helpers |

Dev deps: `vitest`, `@vitest/coverage-istanbul`, `fast-check` (all `catalog:testing`).

---

## Public API surface

### Core

```ts
function defineProtocol(definition: ProtocolDefinition): Protocol

interface Protocol {
  readonly name: string
  readonly version: number
  createSession(options?: SessionOptions): ProtocolSession
  negotiate(offered: ProtocolOffer, signal?: AbortSignal): Promise<ProtocolNegotiationResult>
}

interface ProtocolSession {
  readonly id: string
  readonly state: SessionState
  encode(message: ProtocolMessage): Uint8Array
  decode(data: Uint8Array): ProtocolMessage
  handshake(signal?: AbortSignal): Promise<void>
  close(): void
  on(event: SessionEvent, handler: (data: unknown) => void): () => void
}
```

### Protocol definition

```ts
interface ProtocolDefinition {
  name: string
  version: number
  framing: FramingStrategy
  codecs: ReadonlyArray<MessageCodec<unknown>>
  handshake?: HandshakeDefinition
  maxMessageSize?: number
}

type FramingStrategy =
  | { type: 'length-prefix'; lengthBytes: 2 | 4; bigEndian?: boolean }
  | { type: 'delimiter'; delimiter: Uint8Array }
  | { type: 'fixed'; size: number }

interface MessageCodec<T> {
  readonly type: string
  readonly version?: number
  encode(message: T): Uint8Array
  decode(data: Uint8Array): T
  schema?: { parse: (data: unknown) => T }
}

interface HandshakeDefinition {
  timeout?: number
  clientHello(session: ProtocolSession): Uint8Array
  serverHello(clientData: Uint8Array): Uint8Array
  verify?(data: Uint8Array): boolean
}
```

### Negotiation

```ts
interface ProtocolOffer {
  name: string
  versions: number[]
  capabilities?: string[]
}

interface ProtocolNegotiationResult {
  readonly agreed: boolean
  readonly version: number
  readonly capabilities: string[]
  readonly reason?: string
}
```

### Types

```ts
interface ProtocolMessage {
  type: string
  version?: number
  payload: unknown
  id?: string
  sessionId?: string
}

type SessionState = 'idle' | 'handshaking' | 'established' | 'closing' | 'closed'
type SessionEvent = 'established' | 'message' | 'close' | 'error'

interface SessionOptions {
  logger?: LoggerLike
  clock?: Clock
  eventBus?: EventBusLike
}
```

### Error codes

```ts
type NetworkProtocolErrorCode =
  | 'PROTO_FRAMING_ERROR'
  | 'PROTO_CODEC_NOT_FOUND'
  | 'PROTO_DECODE_FAILED'
  | 'PROTO_ENCODE_FAILED'
  | 'PROTO_HANDSHAKE_FAILED'
  | 'PROTO_VERSION_MISMATCH'
  | 'PROTO_MESSAGE_TOO_LARGE'
  | 'PROTO_ABORT'

function registerNetworkProtocolErrorCodes(): void
```

---

## Genesis additions

1. **Structured `NetworkProtocolError`** with stable `PROTO.*` codes
2. **Zod schemas** for `ProtocolDefinition`, `ProtocolOffer`, `ProtocolMessage`
3. **Three framing strategies** with length-prefix and delimiter implementations using `@suaveplan/crypto-utils` byte helpers
4. **Codec registry** — look up codec by `message.type`; throw `PROTO_CODEC_NOT_FOUND` if missing
5. **Protocol negotiation** — version intersection + capability set intersection
6. **Message size guard** — throw `PROTO_MESSAGE_TOO_LARGE` before encoding
7. **OTel instrumentation** — counter `proto.messages_encoded_total`, `proto.messages_decoded_total`, histogram `proto.message_size_bytes`
8. **Property-based tests** — encode/decode round-trip for arbitrary message payloads; framing idempotency

---

## File layout

```text
universal/network/network-protocol/
  package.json
  tsconfig.json
  vitest.config.ts
  src/
    index.ts
    error-codes.ts
    constants/
      index.ts
    types/
      common.ts
      common.md
    core/
      protocol/
        protocol.ts
        protocol.md
        protocol.types.ts
        protocol.test.ts
        index.ts
      session/
        session.ts
        session.md
        session.test.ts
        index.ts
    framing/
      length-prefix.ts
      length-prefix.md
      length-prefix.test.ts
      delimiter.ts
      delimiter.md
      delimiter.test.ts
      fixed.ts
      fixed.md
      fixed.test.ts
    codecs/
      codec-registry.ts
      codec-registry.md
      codec-registry.test.ts
      index.ts
  tests/
    integration.test.ts
    property.test.ts
```

---

## Impact

**Workspace dep prerequisites**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/events`, `@suaveplan/logger`, `@suaveplan/serialize`, `@suaveplan/crypto-utils` must be published.