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TypeBox is a TypeScript-first schema library. We use it to define the Gateway WebSocket protocol (handshake, request/response, server events). Those schemas drive runtime validation, JSON Schema export, and Swift code generation for the macOS app. Single source of truth; everything else is generated from it. If you want higher-level protocol context, start with Gateway Architecture.

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Mental model (30 sec)

Every Gateway WS message is one of three frames:
  • Request: {"type": "req", "id", "method", "params"}
  • Response: {"type": "res", "id", "ok", "payload | error"}
  • Event: {"type": "event", "event", "payload", "seq?", "stateVersion?"}
The first frame must be a connect request. After that, clients can call methods (for example health, send, chat.send) and subscribe to events (for example presence, tick, agent). Connection flow (minimal example): 
Client                    Gateway
  |---- req:connect -------->|
  |<---- res:hello-ok --------|
  |<---- event:tick ----------|
  |---- req:health ---------->|
  |<---- res:health ----------|
Common methods + events:
CategoryExamplesNotes
Coreconnect, health, statusconnect must be first
Messagingsend, agent, agent.wait, system-event, logs.tailSide effects require idempotencyKey
Chatchat.history, chat.send, chat.abortUsed by WebChat
Sessionssessions.list, sessions.patch, sessions.deleteSession management
Automationwake, cron.list, cron.run, cron.runsWake + scheduled task control
Nodesnode.list, node.invoke, node.pair.*Gateway WS + node operations
Eventstick, presence, agent, chat, health, shutdownServer push
The authoritative published discovery list lives in src/gateway/server-methods-list.ts (listGatewayMethods, GATEWAY_EVENTS).

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Where the schemas live

  • Source: packages/gateway-protocol/src/schema.ts
  • Runtime validators (AJV): packages/gateway-protocol/src/index.ts
  • Advertised feature/discovery registry: src/gateway/server-methods-list.ts
  • Server handshake + method dispatch: src/gateway/server.impl.ts
  • Node client: src/gateway/client.ts
  • Generated JSON Schema: dist/protocol.schema.json
  • Generated Swift models: apps/macos/Sources/OpenClawProtocol/GatewayModels.swift

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Current pipeline

  • pnpm protocol:gen
    • Writes JSON Schema (draft-07) to dist/protocol.schema.json
  • pnpm protocol:gen:swift
    • Generates Swift gateway models
  • pnpm protocol:check
    • Runs both generators and verifies the output is committed

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How these schemas are used at runtime

  • Server: every incoming frame is validated with AJV. The handshake only accepts a connect request whose params match ConnectParams.
  • Client: the JS client validates event and response frames before using them.
  • Feature discovery: Gateway sends a conservative features.methods and features.events list in hello-ok from listGatewayMethods() and GATEWAY_EVENTS.
  • This discovery list is not a generative dump of every callable helper in coreGatewayHandlers; some auxiliary RPC implementations live in src/gateway/server-methods/*.ts but are not published in the feature list.

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Example frames

Connect (first message): 
{
  "type": "req",
  "id": "c1",
  "method": "connect",
  "params": {
    "minProtocol": 3,
    "maxProtocol": 4,
    "client": {
      "id": "openclaw-macos",
      "displayName": "macos",
      "version": "1.0.0",
      "platform": "macos 15.1",
      "mode": "ui",
      "instanceId": "A1B2"
    }
  }
}
Hello-ok response: 
{
  "type": "res",
  "id": "c1",
  "ok": true,
  "payload": {
    "type": "hello-ok",
    "protocol": 4,
    "server": { "version": "dev", "connId": "ws-1" },
    "features": { "methods": ["health"], "events": ["tick"] },
    "snapshot": {
      "presence": [],
      "health": {},
      "stateVersion": { "presence": 0, "health": 0 },
      "uptimeMs": 0
    },
    "policy": { "maxPayload": 1048576, "maxBufferedBytes": 1048576, "tickIntervalMs": 30000 }
  }
}
Request + response: 
{ "type": "req", "id": "r1", "method": "health" }

{ "type": "res", "id": "r1", "ok": true, "payload": { "ok": true } }
Event: 
{ "type": "event", "event": "tick", "payload": { "ts": 1730000000 }, "seq": 12 }

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Minimal client (Node.js)

Minimal usable flow: connect + health. 
import { WebSocket } from "ws";

const ws = new WebSocket("ws://127.0.0.1:18789");

ws.on("open", () => {
  ws.send(
    JSON.stringify({
      type: "req",
      id: "c1",
      method: "connect",
      params: {
        minProtocol: 4,
        maxProtocol: 4,
        client: {
          id: "cli",
          displayName: "example",
          version: "dev",
          platform: "node",
          mode: "cli",
        },
      },
    }),
  );
});

ws.on("message", (data) => {
  const msg = JSON.parse(String(data));
  if (msg.type === "res" && msg.id === "c1" && msg.ok) {
    ws.send(JSON.stringify({ type: "req", id: "h1", method: "health" }));
  }
  if (msg.type === "res" && msg.id === "h1") {
    console.log("health:", msg.payload);
    ws.close();
  }
});

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Practical example: add a method end to end

Example: add a new system.echo request that returns { ok: true, text }.
  1. Schema (single source of truth)
Add to packages/gateway-protocol/src/schema.ts: 
export const SystemEchoParamsSchema = Type.Object(
  { text: NonEmptyString },
  { additionalProperties: false },
);

export const SystemEchoResultSchema = Type.Object(
  { ok: Type.Boolean(), text: NonEmptyString },
  { additionalProperties: false },
);
Add both to ProtocolSchemas and export the types: 
  SystemEchoParams: SystemEchoParamsSchema,
  SystemEchoResult: SystemEchoResultSchema,

export type SystemEchoParams = Static<typeof SystemEchoParamsSchema>;
export type SystemEchoResult = Static<typeof SystemEchoResultSchema>;
  1. Validation
In packages/gateway-protocol/src/index.ts, export an AJV validator: 
export const validateSystemEchoParams = ajv.compile<SystemEchoParams>(SystemEchoParamsSchema);
  1. Server behavior
Add a handler in src/gateway/server-methods/system.ts: 
export const systemHandlers: GatewayRequestHandlers = {
  "system.echo": ({ params, respond }) => {
    const text = String(params.text ?? "");
    respond(true, { ok: true, text });
  },
};
Register it in src/gateway/server-methods.ts (it already merges systemHandlers), then add "system.echo" to the listGatewayMethods input in src/gateway/server-methods-list.ts. If the method is callable by operators or node clients, also classify it in src/gateway/method-scopes.ts so scope enforcement and hello-ok feature publication stay aligned.
  1. Regenerate
pnpm protocol:check
  1. Tests + docs
Add a server test in src/gateway/server.*.test.ts, and document the method.

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Swift code generation behavior

The Swift generator outputs:
  • GatewayFrame enum with req, res, event, and unknown cases
  • Strongly typed payload structs/enums
  • ErrorCode values, GATEWAY_PROTOCOL_VERSION, and GATEWAY_MIN_PROTOCOL_VERSION
Unknown frame types are preserved as raw payloads to keep forward compatibility.

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Versioning + compatibility

  • PROTOCOL_VERSION lives in packages/gateway-protocol/src/version.ts.
  • Clients send minProtocol + maxProtocol; the server rejects ranges that do not include the current protocol.
  • The Swift models keep unknown frame types to avoid breaking older clients.

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Schema patterns and conventions

  • Most objects use additionalProperties: false to keep payloads strict.
  • NonEmptyString is the default choice for IDs and method/event names.
  • The top-level GatewayFrame uses a discriminator on type.
  • Methods with side effects typically require idempotencyKey in params (for example send, poll, agent, chat.send).
  • agent accepts optional internalEvents for runtime-generated orchestration context (for example sub-agent/cron handoff completion); treat it as an internal API surface.

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Live schema JSON

The generated JSON Schema lives in dist/protocol.schema.json in the repo. The published raw file is usually available at:

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When you change schemas

  1. Update the TypeBox schema.
  2. Register the method/event in src/gateway/server-methods-list.ts.
  3. Update src/gateway/method-scopes.ts when a new RPC needs operator or node scope classification.
  4. Run pnpm protocol:check.
  5. Commit the regenerated schema + Swift models.