TypeBox

TypeBox is a TypeScript-first schema library. OpenClaw uses it to define the Gateway WebSocket protocol (handshake, request/response, server events). Those schemas drive runtime validation (TypeBox Compile), JSON Schema export, and Swift codegen for the macOS app. One source of truth; everything else is generated.

For the higher-level protocol context, start with Gateway architecture.

Mental model (30 seconds)

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 call methods (e.g. health, send, chat.send) and subscribe to events (e.g. presence, tick, agent).

Connection flow (minimal):

Client                    Gateway  |---- req:connect -------->|  |<---- res:hello-ok --------|  |<---- event:tick ----------|  |---- req:health ---------->|  |<---- res:health ----------|

Common methods and events:

The authoritative advertised discovery inventory lives in src/gateway/server-methods-list.ts (listGatewayMethods, GATEWAY_EVENTS).

Where the schemas live

• Source barrels: packages/gateway-protocol/src/schema-modules.ts owns the canonical domain-module list, while the public schema.ts wrapper also exposes ProtocolSchemas.
• Generator selection: packages/gateway-protocol/src/schema/protocol-schema-selection.ts derives registry names from the canonical barrel's *Schema exports and explicit skill-library.ts imports, removing the Schema suffix. EXCLUDED_SCHEMA_EXPORTS keeps helpers and schemas with supplemental registry owners out of this derived selection.
• Generator registry: protocol-schemas.ts composes the derived selection, MigrationProtocolSchemas, and SessionPlacementProtocolSchemas, rejecting duplicate keys and retaining the canonical TypeBox objects. protocol-schema-types.ts preserves each member's schema type and public readonly/writable modifiers.
• Runtime validators: packages/gateway-protocol/src/validator-registry.ts, using the lazy TypeBox Compile owner in protocol-validator.ts
• Advertised feature/discovery registry: src/gateway/server-methods-list.ts
• Server handshake and method dispatch: src/gateway/server-core-runtime.ts
• Node client: src/gateway/client.ts
• Generated JSON Schema: dist/protocol.schema.json (build output, not committed)
• Generated Swift models: apps/shared/OpenClawKit/Sources/OpenClawProtocol/GatewayModels.swift

The derived selection uses lexical order of the full source export names before removing the Schema suffix. The migration and session-placement maps follow it in their own insertion order. This replaces the former manually ordered registration fragments; JSON definition order and Swift declaration placement can change without changing schema data or native declaration bodies.

Membership is now opt-out for eligible source exports: a new *Schema export in the canonical barrel enters the generator registry unless explicitly excluded. Review each new export for intended generated-protocol membership, and add helper-only exports to EXCLUDED_SCHEMA_EXPORTS. The registry guard checks selection consistency, canonical objects, exclusions, and composition; it cannot independently determine whether a newly exported schema belongs in the public generated protocol.

Current pipeline

• pnpm protocol:gen writes JSON Schema (draft-07) to dist/protocol.schema.json.
• pnpm protocol:gen:swift generates the Swift gateway models.
• pnpm protocol:check:swift verifies the committed Swift models without rewriting them.
• pnpm protocol:gen:kotlin generates the Android protocol models and constants.
• pnpm protocol:check checks the registry structure, runs all three generators, and verifies the committed Swift and Kotlin output. The JSON Schema output is a gitignored build artifact with no committed baseline to diff against, so pnpm protocol:gen instead asserts the published-document contract (required frame definitions, frame ordering, type discriminator mapping, non-empty method metadata) and fails the check when the generated schema drifts from it.

When a gateway schema affects native clients, run pnpm protocol:gen:swift, review the generated diff, then run pnpm protocol:check:swift. Commit the schema and GatewayModels.swift update together. Stable decoding behavior belongs in the focused GatewayModelsCompatibilityTests.swift regressions rather than in handwritten model copies.

How the schemas are used at runtime

• Server side: every inbound frame is validated with TypeBox Compile. The handshake only accepts a connect request whose params match ConnectParams.
• Client side: the JS client validates event and response frames before using them.
• Feature discovery: the Gateway sends a conservative features.methods and features.events list in hello-ok, from listGatewayMethods() and GATEWAY_EVENTS.
• That discovery list is not a generated dump of every callable helper in coreGatewayHandlers; some helper RPCs are implemented in src/gateway/server-methods/*.ts without being enumerated in the advertised feature list.

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    },    "auth": { "role": "operator", "scopes": ["operator.read"] },    "policy": { "maxPayload": 1048576, "maxBufferedBytes": 1048576, "tickIntervalMs": 30000 }  }}

Request and 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 }

Minimal client (Node.js)

Smallest useful 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();  }});

Worked example: add a method end-to-end

Example: add a new system.echo request that returns { ok: true, text }.

1. Schema (source of truth)

Add to packages/gateway-protocol/src/schema/system-info.ts (or the closest matching feature module):

export const SystemEchoParamsSchema = Type.Object(  { text: NonEmptyString },  { additionalProperties: false },); export const SystemEchoResultSchema = Type.Object(  { ok: Type.Boolean(), text: NonEmptyString },  { additionalProperties: false },);

system-info.ts is already exported by packages/gateway-protocol/src/schema-modules.ts, so both schemas enter ProtocolSchemas automatically as SystemEchoParams and SystemEchoResult. For a new owner module, add its export to that canonical barrel. Review any other *Schema exports it introduces and exclude helper-only schemas in protocol-schema-selection.ts. Keep schemas owned by the migration or session-placement maps in those maps and excluded from the derived selection.

Export the corresponding static types from the owner module:

export type SystemEchoParams = Static<typeof SystemEchoParamsSchema>;export type SystemEchoResult = Static<typeof SystemEchoResultSchema>;

2. Validation

In packages/gateway-protocol/src/validator-registry.ts, export a validator using its existing lazy compiler:

export const validateSystemEchoParams = compile(S.SystemEchoParamsSchema);

3. 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 (already merges systemHandlers), then add "system.echo" to the listGatewayMethods input in src/gateway/server-methods-list.ts.

If the method is callable by operator or node clients, also classify it in src/gateway/method-scopes.ts so scope enforcement and hello-ok feature advertising stay aligned.

4. Regenerate

pnpm protocol:check

5. Tests and docs

Add a server test in src/gateway/server.*.test.ts and note the method in docs.

Swift codegen behavior

The Swift generator emits:

• a 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 for forward compatibility.

Some registry names alias the same canonical schema object. The explicit canonical alias preferences in scripts/protocol-gen-swift.ts preserve the existing public Swift type names when registry enumeration changes. Review generated declaration bodies, including field types, initializers, and encoding/decoding behavior; moving declarations must not silently select different nominal types.

The published JSON Schema's oneOf frame order is a separate contract: req, res, then event, with the matching type discriminator mapping. scripts/lib/protocol-schema-document.mts owns and checks that order independently of registry definition order.

Versioning and compatibility

• PROTOCOL_VERSION lives in packages/gateway-protocol/src/version.ts (current value: 4).
• Clients send minProtocol and maxProtocol; the server rejects ranges that do not include its current protocol.
• The Swift models keep unknown frame types to avoid breaking older clients.

Schema patterns and conventions

• Most objects use additionalProperties: false for strict payloads.
• NonEmptyString (Type.String({ minLength: 1 })) is the default for IDs and method/event names.
• The top-level GatewayFrame uses a discriminator on type.
• Methods with side effects usually require an idempotencyKey in params (example: send, poll, agent, chat.send).
• agent accepts optional internalEvents for runtime-generated orchestration context (for example subagent/cron task completion handoff); treat this as internal API surface.

Live schema JSON

Generated JSON Schema is a build artifact, not committed to the repo. During the package rollout, the current beta schema is available at:

• protocol.schema.json

When you change schemas

1. Update the TypeBox schemas in the owning packages/gateway-protocol/src/schema/*.ts module. Ensure a new module is exported by schema-modules.ts, review its automatic *Schema membership, and update helper exclusions or existing supplemental owner maps as needed.
2. Register the method/event in src/gateway/server-methods-list.ts.
3. Update src/gateway/method-scopes.ts when the new RPC needs operator or node scope classification.
4. Run pnpm protocol:check.
5. Commit the regenerated Swift models.

Related

• Rich output protocol
• RPC adapters