diff --git a/README.md b/README.md
index ea9d906..dc50cad 100644
--- a/README.md
+++ b/README.md
@@ -931,6 +931,9 @@ Methods:
 - `system.nodes` returns registered node snapshots (role, capabilities, identity, location/status).
 - `system.capabilities` returns gateway protocol and node policy snapshot.
 
+Companion runtime helper:
+- `src/companion/runtimeClient.ts` provides a typed Node/WebSocket client for companion runtimes (macOS/iOS/Android workers) with wrappers for `node.register`, `node.capabilities.get`, `node.location.set/get`, `node.status.set`, `node.push_token.set`, `system.capabilities`, and `system.nodes`.
+
 ## Canvas / A2UI Foundation
 
 Gateway provides a session-scoped canvas artifact API for companion/UI surfaces:
diff --git a/docs/api/PROTOCOL.md b/docs/api/PROTOCOL.md
index fae7210..38bc367 100644
--- a/docs/api/PROTOCOL.md
+++ b/docs/api/PROTOCOL.md
@@ -1290,3 +1290,4 @@ For more implementation details, see:
 - Protocol types: `src/gateway/protocol.ts`
 - Handlers: `src/gateway/handlers/`
 - Gateway server: `src/gateway/server.ts`
+- Companion runtime client helper: `src/companion/runtimeClient.ts`
diff --git a/docs/architecture/CONTRIBUTOR_MAP.md b/docs/architecture/CONTRIBUTOR_MAP.md
index ca30257..ae9cbc8 100644
--- a/docs/architecture/CONTRIBUTOR_MAP.md
+++ b/docs/architecture/CONTRIBUTOR_MAP.md
@@ -22,6 +22,7 @@ src/
   models/        Provider clients + model router + retry/cost/capabilities
   channels/      Chat adapters + pairing gate (Telegram/Discord/Slack/WhatsApp/Matrix/Signal/Mattermost/LINE/Feishu/Zalo/etc.)
   gateway/       WebSocket JSON-RPC server + web UI + handlers
+  companion/     Node-side companion runtime client for gateway node/system RPC
   memory/        Hybrid search + embeddings + persistence
   session/       SQLite store + session mgmt
   cli/           CLI entrypoints + setup wizard
diff --git a/docs/plans/2026-02-16-companion-runtime-client-foundation-checklist.md b/docs/plans/2026-02-16-companion-runtime-client-foundation-checklist.md
new file mode 100644
index 0000000..dd72857
--- /dev/null
+++ b/docs/plans/2026-02-16-companion-runtime-client-foundation-checklist.md
@@ -0,0 +1,37 @@
+# Companion Runtime Client Foundation Checklist (2026-02-16)
+
+## Scope
+
+- Add a reusable Node/WebSocket runtime client for companion apps to call gateway node/system RPC methods without manually handling request IDs, pending maps, or error-code parsing.
+- Keep API focused on current companion milestones:
+  - `node.register`
+  - `node.capabilities.get`
+  - `node.location.set/get`
+  - `node.status.set`
+  - `node.push_token.set`
+  - `system.capabilities`
+  - `system.nodes`
+
+## Implementation
+
+- Added `src/companion/runtimeClient.ts`:
+  - `CompanionRuntimeClient` typed wrapper around gateway JSON-RPC over `ws`.
+  - `GatewayRpcError` carrying gateway error code + message.
+  - Connection lifecycle (`connect`, `disconnect`, `connected`) and typed `call<T>()`.
+  - Method-specific wrappers for node/system companion RPCs.
+  - Token query-param support for gateway bearer auth.
+- Added `src/companion/index.ts` exports for companion runtime integration.
+- Added `src/companion/runtimeClient.test.ts` integration coverage against live `GatewayServer` fixture.
+
+## Validation
+
+- Companion runtime tests:
+  - registration + capability flow
+  - status/location/push updates and `system.nodes` visibility
+  - RPC error mapping into `GatewayRpcError`
+
+## Docs Updated
+
+- `README.md` (Gateway Node Capability Negotiation section): references `src/companion/runtimeClient.ts` helper.
+- `docs/api/PROTOCOL.md`: implementation reference updated with runtime client helper.
+- `docs/architecture/CONTRIBUTOR_MAP.md`: repo tour now includes `src/companion/`.
diff --git a/docs/plans/state.json b/docs/plans/state.json
index 8f19797..98a3f5b 100644
--- a/docs/plans/state.json
+++ b/docs/plans/state.json
@@ -707,6 +707,25 @@
       ],
       "test_status": "pnpm test:run src/channels/zalo/adapter.test.ts src/daemon/channels.test.ts src/config/schema.test.ts src/gateway/handlers/services.test.ts + pnpm typecheck + pnpm build passing"
     },
+    "companion-runtime-client-foundation": {
+      "file": "2026-02-16-companion-runtime-client-foundation-checklist.md",
+      "status": "completed",
+      "date": "2026-02-16",
+      "updated": "2026-02-16",
+      "summary": "Added a reusable companion runtime gateway client (`CompanionRuntimeClient`) for Node/WebSocket JSON-RPC with typed wrappers for node registration/capability/status/location/push and operator system capability/node listing methods, including RPC error-code mapping and integration tests.",
+      "files_created": [
+        "docs/plans/2026-02-16-companion-runtime-client-foundation-checklist.md",
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "src/companion/index.ts"
+      ],
+      "files_modified": [
+        "README.md",
+        "docs/api/PROTOCOL.md",
+        "docs/architecture/CONTRIBUTOR_MAP.md"
+      ],
+      "test_status": "pnpm test:run src/companion/runtimeClient.test.ts + pnpm typecheck + pnpm build passing"
+    },
     "qmd-backend": {
       "file": "2026-02-16-qmd-backend-checklist.md",
       "status": "completed",
@@ -3268,7 +3287,7 @@
     }
   },
   "overall_progress": {
-    "total_test_count": 1814,
+    "total_test_count": 1817,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",
@@ -3288,7 +3307,7 @@
     "gmail_auth_cli": "flynn gmail-auth command implemented with OAuth2 flow, doctor check, config routed to Telegram",
     "native_audio_support": "completed — smart routing for native audio (Gemini/OpenAI/GitHub) vs Whisper transcription fallback",
     "remaining_phases_completion": "Phase 1: 3/3 (100%) — context levels, command registry, memory structure. Phase 2: 3/3 (100%) — component registry, confidence routing, history index. Phase 3: 2/2 (100%) — adaptive memory/compaction, truthfulness/autonomy hardening",
-    "next_up": "OpenClaw gap: companion app runtime clients (macOS/iOS/Android implementation) — open next scoped implementation checklist"
+    "next_up": "OpenClaw gap: implement macOS/iOS/Android companion runtime clients on top of `src/companion/runtimeClient.ts`"
   },
   "soul_md_and_cron_create": {
     "date": "2026-02-11",
diff --git a/src/companion/index.ts b/src/companion/index.ts
new file mode 100644
index 0000000..92cd25f
--- /dev/null
+++ b/src/companion/index.ts
@@ -0,0 +1,25 @@
+export {
+  CompanionRuntimeClient,
+  GatewayRpcError,
+} from './runtimeClient.js';
+
+export type {
+  CompanionRuntimeClientOptions,
+  RegisterNodeInput,
+  ListNodesInput,
+  SetNodeStatusInput,
+  SetNodeLocationInput,
+  SetNodePushTokenInput,
+  NodeRegisterResult,
+  NodeCapabilitiesResult,
+  NodeStatusSetResult,
+  NodeLocationSetResult,
+  NodeLocationGetResult,
+  NodePushTokenSetResult,
+  SystemCapabilitiesResult,
+  SystemNodesResult,
+  SystemNodeEntry,
+  NodeLocation,
+  NodeStatus,
+  NodePushSummary,
+} from './runtimeClient.js';
diff --git a/src/companion/runtimeClient.test.ts b/src/companion/runtimeClient.test.ts
new file mode 100644
index 0000000..91dcdaa
--- /dev/null
+++ b/src/companion/runtimeClient.test.ts
@@ -0,0 +1,227 @@
+import { describe, it, expect, beforeAll, afterAll, vi } from 'vitest';
+import { resolve } from 'path';
+import { createServer } from 'net';
+import type { GatewayServerConfig } from '../gateway/server.js';
+import { GatewayServer } from '../gateway/server.js';
+import { CompanionRuntimeClient, GatewayRpcError } from './runtimeClient.js';
+
+async function canListenOnLocalhost(): Promise<boolean> {
+  return new Promise((resolvePromise) => {
+    const s = createServer();
+    s.once('error', () => resolvePromise(false));
+    s.listen(0, '127.0.0.1', () => {
+      s.close(() => resolvePromise(true));
+    });
+  });
+}
+
+const mockSession = {
+  id: 'test',
+  addMessage: vi.fn(),
+  getHistory: vi.fn(() => []),
+  clear: vi.fn(),
+  setHistory: vi.fn(),
+  replaceHistory: vi.fn(),
+};
+
+const mockSessionManager = {
+  getSession: vi.fn(() => mockSession),
+  listSessions: vi.fn(() => ['ws:test']),
+  transferSession: vi.fn(),
+  closeSession: vi.fn(),
+};
+
+const mockModelClient = {
+  chat: vi.fn(async () => ({
+    content: 'Hello from Flynn!',
+    stopReason: 'end_turn',
+    usage: { inputTokens: 10, outputTokens: 5 },
+  })),
+};
+
+const mockToolRegistry = {
+  register: vi.fn(),
+  get: vi.fn(),
+  list: vi.fn(() => []),
+  filteredList: vi.fn(() => []),
+  toAnthropicFormat: vi.fn(() => []),
+  toOpenAIFormat: vi.fn(() => []),
+  filteredToAnthropicFormat: vi.fn(() => []),
+  filteredToOpenAIFormat: vi.fn(() => []),
+};
+
+const mockToolExecutor = {
+  execute: vi.fn(async () => ({ success: true, output: 'ok' })),
+};
+
+const TEST_PORT = 18911;
+const TEST_TOKEN = 'runtime-client-token';
+
+let LISTEN_ALLOWED = true;
+let server: GatewayServer;
+
+beforeAll(async () => {
+  LISTEN_ALLOWED = await canListenOnLocalhost();
+  if (!LISTEN_ALLOWED) {
+    return;
+  }
+
+  server = new GatewayServer({
+    port: TEST_PORT,
+    sessionManager: mockSessionManager as unknown as GatewayServerConfig['sessionManager'],
+    modelClient: mockModelClient,
+    systemPrompt: 'Test prompt',
+    toolRegistry: mockToolRegistry as unknown as GatewayServerConfig['toolRegistry'],
+    toolExecutor: mockToolExecutor as unknown as GatewayServerConfig['toolExecutor'],
+    version: '0.1.0-test',
+    uiDir: resolve(import.meta.dirname, '../gateway/ui'),
+    auth: { token: TEST_TOKEN },
+    nodes: {
+      enabled: true,
+      allowedRoles: ['companion'],
+      featureGates: { 'ui.canvas': true },
+      locationEnabled: true,
+      pushEnabled: true,
+    },
+  });
+
+  await server.start();
+});
+
+afterAll(async () => {
+  if (!LISTEN_ALLOWED) {
+    return;
+  }
+  await server.stop();
+});
+
+describe('CompanionRuntimeClient', () => {
+  it('connects and performs node registration + capability discovery', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const client = new CompanionRuntimeClient({
+      url: `ws://127.0.0.1:${TEST_PORT}`,
+      token: TEST_TOKEN,
+    });
+
+    await client.connect();
+    expect(client.connected).toBe(true);
+
+    try {
+      const register = await client.registerNode({
+        nodeId: 'macos-companion',
+        role: 'companion',
+        capabilities: ['ui.canvas', 'node.location.read'],
+      });
+
+      expect(register.registered).toBe(true);
+      expect(register.node.id).toBe('macos-companion');
+      expect(register.protocol.serverVersion).toBe(1);
+      expect(register.capabilities.enabled).toContain('ui.canvas');
+
+      const nodeCaps = await client.getNodeCapabilities();
+      expect(nodeCaps.node.id).toBe('macos-companion');
+      expect(nodeCaps.capabilities.enabled).toContain('ui.canvas');
+
+      const systemCaps = await client.getSystemCapabilities();
+      expect(systemCaps.nodes.enabled).toBe(true);
+      expect(systemCaps.nodes.registered).toBe(true);
+      expect(systemCaps.nodes.nodeId).toBe('macos-companion');
+    } finally {
+      client.disconnect();
+    }
+  });
+
+  it('updates status/location/push and exposes them through system.nodes', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const client = new CompanionRuntimeClient({
+      url: `ws://127.0.0.1:${TEST_PORT}`,
+      token: TEST_TOKEN,
+    });
+
+    await client.connect();
+
+    try {
+      await client.registerNode({
+        nodeId: 'ios-companion',
+        role: 'companion',
+        capabilities: ['node.location.write', 'node.push.register'],
+      });
+
+      const status = await client.setNodeStatus({
+        platform: 'ios',
+        appVersion: '1.2.3',
+        batteryPct: 77,
+        powerSource: 'battery',
+      });
+      expect(status.updated).toBe(true);
+      expect(status.status.platform).toBe('ios');
+
+      const location = await client.setNodeLocation({
+        latitude: 37.78,
+        longitude: -122.41,
+        source: 'gps',
+      });
+      expect(location.updated).toBe(true);
+      expect(location.location.source).toBe('gps');
+
+      const locationGet = await client.getNodeLocation();
+      expect(locationGet.location?.latitude).toBe(37.78);
+
+      const push = await client.setNodePushToken({
+        provider: 'apns',
+        token: 'abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890',
+        topic: 'dev.flynn.companion',
+        environment: 'production',
+      });
+      expect(push.updated).toBe(true);
+      expect(push.push.provider).toBe('apns');
+      expect(push.push.tokenPreview.startsWith('***')).toBe(true);
+
+      const nodes = await client.listSystemNodes({ role: 'companion', platform: 'ios' });
+      expect(nodes.summary.total).toBeGreaterThanOrEqual(1);
+      const current = nodes.nodes.find((entry) => entry.nodeId === 'ios-companion');
+      expect(current).toBeTruthy();
+      expect(current?.status?.platform).toBe('ios');
+      expect(current?.push?.provider).toBe('apns');
+    } finally {
+      client.disconnect();
+    }
+  });
+
+  it('surfaces gateway errors as GatewayRpcError', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const client = new CompanionRuntimeClient({
+      url: `ws://127.0.0.1:${TEST_PORT}`,
+      token: TEST_TOKEN,
+    });
+
+    await client.connect();
+
+    try {
+      await expect(client.registerNode({
+        nodeId: 'observer-node',
+        role: 'observer',
+        capabilities: ['node.location.read'],
+      })).rejects.toBeInstanceOf(GatewayRpcError);
+
+      await expect(client.registerNode({
+        nodeId: 'observer-node',
+        role: 'observer',
+        capabilities: ['node.location.read'],
+      })).rejects.toMatchObject({
+        code: -5,
+      });
+    } finally {
+      client.disconnect();
+    }
+  });
+});
diff --git a/src/companion/runtimeClient.ts b/src/companion/runtimeClient.ts
new file mode 100644
index 0000000..805f03e
--- /dev/null
+++ b/src/companion/runtimeClient.ts
@@ -0,0 +1,429 @@
+import { WebSocket } from 'ws';
+import type {
+  NodeLocationSetParams,
+  NodePushTokenSetParams,
+  NodeStatusSetParams,
+} from '../gateway/protocol.js';
+import { GATEWAY_PROTOCOL_VERSION } from '../gateway/protocol.js';
+
+interface RpcSuccess {
+  id: number;
+  result: unknown;
+}
+
+interface RpcFailure {
+  id: number;
+  error: {
+    code: number;
+    message: string;
+  };
+}
+
+interface RpcEvent {
+  id: number;
+  event: string;
+  data: unknown;
+}
+
+type RpcMessage = RpcSuccess | RpcFailure | RpcEvent;
+
+type PendingRequest = {
+  resolve: (value: unknown) => void;
+  reject: (error: Error) => void;
+  timeout: NodeJS.Timeout;
+};
+
+export interface CompanionRuntimeClientOptions {
+  url: string;
+  token?: string;
+  requestTimeoutMs?: number;
+  websocketFactory?: (url: string) => WebSocket;
+}
+
+export interface RegisterNodeInput {
+  nodeId: string;
+  role: string;
+  capabilities: string[];
+  protocolVersion?: number;
+}
+
+export interface NodeIdentitySummary {
+  id: string;
+  role: string;
+}
+
+export interface NodeRegisterResult {
+  registered: boolean;
+  node: NodeIdentitySummary;
+  protocol: {
+    serverVersion: number;
+    clientVersion: number;
+    negotiatedVersion: number;
+  };
+  capabilities: {
+    declared: string[];
+    enabled: string[];
+  };
+}
+
+export interface NodeCapabilitiesResult {
+  protocol: {
+    serverVersion: number;
+    nodeVersion: number;
+    negotiatedVersion: number;
+  };
+  node: {
+    id: string;
+    role: string;
+    registeredAt: number;
+  };
+  capabilities: {
+    declared: string[];
+    enabled: string[];
+    featureGates: Record<string, boolean>;
+  };
+}
+
+export interface NodeStatus {
+  platform: 'macos' | 'ios' | 'android' | 'linux' | 'windows' | 'unknown';
+  appVersion?: string;
+  deviceName?: string;
+  statusText?: string;
+  batteryPct?: number;
+  powerSource: 'ac' | 'battery' | 'unknown';
+  reportedAt: number;
+}
+
+export interface NodeLocation {
+  latitude: number;
+  longitude: number;
+  accuracyMeters?: number;
+  altitudeMeters?: number;
+  headingDegrees?: number;
+  speedMps?: number;
+  source: 'gps' | 'network' | 'manual' | 'unknown';
+  capturedAt: number;
+  receivedAt: number;
+}
+
+export interface NodePushSummary {
+  provider: 'apns' | 'fcm';
+  tokenPreview: string;
+  topic?: string;
+  environment?: 'sandbox' | 'production';
+  registeredAt: number;
+}
+
+export interface NodeStatusSetResult {
+  updated: boolean;
+  node: NodeIdentitySummary;
+  status: NodeStatus;
+}
+
+export interface NodeLocationSetResult {
+  updated: boolean;
+  node: NodeIdentitySummary;
+  location: NodeLocation;
+}
+
+export interface NodePushTokenSetResult {
+  updated: boolean;
+  node: NodeIdentitySummary;
+  push: NodePushSummary;
+}
+
+export interface NodeLocationGetResult {
+  node: NodeIdentitySummary;
+  location: NodeLocation | null;
+}
+
+export interface SystemCapabilitiesResult {
+  protocol: {
+    version: number;
+  };
+  nodes: {
+    enabled: boolean;
+    locationEnabled: boolean;
+    pushEnabled: boolean;
+    allowedRoles: string[];
+    registered: boolean;
+    role?: string;
+    nodeId?: string;
+  };
+  featureGates: Record<string, boolean>;
+}
+
+export interface SystemNodeEntry {
+  connectionId: string;
+  nodeId: string;
+  role: string;
+  identity?: string;
+  protocolVersion: number;
+  capabilities: string[];
+  registeredAt: number;
+  location?: NodeLocation;
+  status?: NodeStatus;
+  push?: NodePushSummary;
+}
+
+export interface SystemNodesResult {
+  nodes: SystemNodeEntry[];
+  summary: {
+    total: number;
+  };
+}
+
+export interface ListNodesInput {
+  role?: string;
+  platform?: string;
+  limit?: number;
+}
+
+export interface SetNodeStatusInput extends Omit<NodeStatusSetParams, 'connectionId'> {}
+
+export interface SetNodeLocationInput extends Omit<NodeLocationSetParams, 'connectionId'> {}
+
+export interface SetNodePushTokenInput extends Omit<NodePushTokenSetParams, 'connectionId'> {}
+
+export class GatewayRpcError extends Error {
+  readonly code: number;
+
+  constructor(code: number, message: string) {
+    super(message);
+    this.name = 'GatewayRpcError';
+    this.code = code;
+  }
+}
+
+export class CompanionRuntimeClient {
+  private readonly url: string;
+  private readonly token?: string;
+  private readonly requestTimeoutMs: number;
+  private readonly websocketFactory: (url: string) => WebSocket;
+
+  private ws: WebSocket | null = null;
+  private nextId = 1;
+  private pending = new Map<number, PendingRequest>();
+
+  constructor(options: CompanionRuntimeClientOptions) {
+    this.url = options.url;
+    this.token = options.token;
+    this.requestTimeoutMs = options.requestTimeoutMs ?? 15_000;
+    this.websocketFactory = options.websocketFactory ?? ((url) => new WebSocket(url));
+  }
+
+  get connected(): boolean {
+    return this.ws?.readyState === WebSocket.OPEN;
+  }
+
+  async connect(): Promise<void> {
+    if (this.connected) {
+      return;
+    }
+
+    const ws = this.websocketFactory(withToken(this.url, this.token));
+
+    await new Promise<void>((resolve, reject) => {
+      let settled = false;
+
+      const onOpen = () => {
+        cleanup();
+        settled = true;
+        this.ws = ws;
+        this.ws.on('message', (raw) => this.handleMessage(raw.toString()));
+        this.ws.on('close', () => this.rejectAllPending(new Error('WebSocket closed')));
+        this.ws.on('error', () => {
+          // close event handles pending rejection
+        });
+        resolve();
+      };
+
+      const onError = (err: Error) => {
+        cleanup();
+        settled = true;
+        reject(err);
+      };
+
+      const onClose = () => {
+        cleanup();
+        if (!settled) {
+          settled = true;
+          reject(new Error('WebSocket closed before connection established'));
+        }
+      };
+
+      const cleanup = () => {
+        ws.off('open', onOpen);
+        ws.off('error', onError);
+        ws.off('close', onClose);
+      };
+
+      ws.once('open', onOpen);
+      ws.once('error', onError);
+      ws.once('close', onClose);
+    });
+  }
+
+  disconnect(code?: number, reason?: string): void {
+    if (!this.ws) {
+      return;
+    }
+
+    const ws = this.ws;
+    this.ws = null;
+    this.rejectAllPending(new Error('Disconnected'));
+    ws.close(code, reason);
+  }
+
+  async call<T>(method: string, params?: Record<string, unknown>): Promise<T> {
+    if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
+      throw new Error('WebSocket is not connected');
+    }
+
+    const id = this.nextId++;
+
+    return new Promise<T>((resolve, reject) => {
+      const timeout = setTimeout(() => {
+        this.pending.delete(id);
+        reject(new Error(`RPC timeout for method ${method}`));
+      }, this.requestTimeoutMs);
+
+      this.pending.set(id, {
+        resolve: (value) => {
+          clearTimeout(timeout);
+          resolve(value as T);
+        },
+        reject: (error) => {
+          clearTimeout(timeout);
+          reject(error);
+        },
+        timeout,
+      });
+
+      this.ws?.send(JSON.stringify({ id, method, params: params ?? {} }), (err) => {
+        if (!err) {
+          return;
+        }
+
+        const pending = this.pending.get(id);
+        if (!pending) {
+          return;
+        }
+        clearTimeout(pending.timeout);
+        this.pending.delete(id);
+        reject(err);
+      });
+    });
+  }
+
+  registerNode(input: RegisterNodeInput): Promise<NodeRegisterResult> {
+    return this.call<NodeRegisterResult>('node.register', {
+      nodeId: input.nodeId,
+      role: input.role,
+      protocolVersion: input.protocolVersion ?? GATEWAY_PROTOCOL_VERSION,
+      capabilities: input.capabilities,
+    });
+  }
+
+  getNodeCapabilities(): Promise<NodeCapabilitiesResult> {
+    return this.call<NodeCapabilitiesResult>('node.capabilities.get');
+  }
+
+  setNodeStatus(input: SetNodeStatusInput): Promise<NodeStatusSetResult> {
+    return this.call<NodeStatusSetResult>('node.status.set', {
+      platform: input.platform,
+      appVersion: input.appVersion,
+      deviceName: input.deviceName,
+      statusText: input.statusText,
+      batteryPct: input.batteryPct,
+      powerSource: input.powerSource,
+    });
+  }
+
+  setNodeLocation(input: SetNodeLocationInput): Promise<NodeLocationSetResult> {
+    return this.call<NodeLocationSetResult>('node.location.set', {
+      latitude: input.latitude,
+      longitude: input.longitude,
+      accuracyMeters: input.accuracyMeters,
+      altitudeMeters: input.altitudeMeters,
+      headingDegrees: input.headingDegrees,
+      speedMps: input.speedMps,
+      source: input.source,
+      capturedAt: input.capturedAt,
+    });
+  }
+
+  getNodeLocation(): Promise<NodeLocationGetResult> {
+    return this.call<NodeLocationGetResult>('node.location.get');
+  }
+
+  setNodePushToken(input: SetNodePushTokenInput): Promise<NodePushTokenSetResult> {
+    return this.call<NodePushTokenSetResult>('node.push_token.set', {
+      provider: input.provider,
+      token: input.token,
+      topic: input.topic,
+      environment: input.environment,
+    });
+  }
+
+  getSystemCapabilities(): Promise<SystemCapabilitiesResult> {
+    return this.call<SystemCapabilitiesResult>('system.capabilities');
+  }
+
+  listSystemNodes(input?: ListNodesInput): Promise<SystemNodesResult> {
+    return this.call<SystemNodesResult>('system.nodes', {
+      role: input?.role,
+      platform: input?.platform,
+      limit: input?.limit,
+    });
+  }
+
+  private handleMessage(raw: string): void {
+    let parsed: RpcMessage;
+    try {
+      parsed = JSON.parse(raw) as RpcMessage;
+    } catch {
+      return;
+    }
+
+    if (!('id' in parsed) || typeof parsed.id !== 'number') {
+      return;
+    }
+
+    if ('event' in parsed) {
+      return;
+    }
+
+    const pending = this.pending.get(parsed.id);
+    if (!pending) {
+      return;
+    }
+
+    this.pending.delete(parsed.id);
+
+    if ('error' in parsed) {
+      pending.reject(new GatewayRpcError(parsed.error.code, parsed.error.message));
+      return;
+    }
+
+    pending.resolve(parsed.result);
+  }
+
+  private rejectAllPending(error: Error): void {
+    for (const [, pending] of this.pending) {
+      clearTimeout(pending.timeout);
+      pending.reject(error);
+    }
+    this.pending.clear();
+  }
+}
+
+function withToken(url: string, token?: string): string {
+  if (!token) {
+    return url;
+  }
+
+  const parsed = new URL(url);
+  parsed.searchParams.set('token', token);
+  return parsed.toString();
+}