diff --git a/CHANGELOG.md b/CHANGELOG.md
index eb125d153..42e8e687f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@
 - Added strict `wait absent <selector> [timeoutMs]` polling for zero selector matches. Incomplete,
   sparse, truncated, scoped, depth-limited, and Android unreadable captures cannot prove absence;
   deadline diagnostics retain typed capture evidence and stable first-match details (#2236).
+- Added the `harmonyos-instance` lease contract and CLI/runtime plumbing as a prerequisite for
+  HarmonyOS proxy support; provider/daemon allocation remains gated until its end-to-end lifecycle
+  is implemented and validated (#2266).
+
 - Fixed: `settings airplane on|off` now takes an Android device offline. It is applied through
   the connectivity service (`cmd connectivity airplane-mode`), which drives the radios, instead of
   writing `airplane_mode_on` and broadcasting `ACTION_AIRPLANE_MODE_CHANGED` — a broadcast Android
diff --git a/packages/kernel/src/contracts.ts b/packages/kernel/src/contracts.ts
index a42a4154b..a42ee3462 100644
--- a/packages/kernel/src/contracts.ts
+++ b/packages/kernel/src/contracts.ts
@@ -5,7 +5,7 @@ export { defaultHintForCode, normalizeError } from './errors.ts';
 import type { PlatformSelector } from './device.ts';
 
 export type SessionRuntimeHints = {
-  platform?: 'ios' | 'android';
+  platform?: 'ios' | 'android' | 'harmonyos';
   metroHost?: string;
   metroPort?: number;
   bundleUrl?: string;
@@ -44,7 +44,7 @@ export type LocalInstallSource = Extract<DaemonInstallSource, { kind: 'url' | 'p
 
 const DAEMON_LOCK_POLICIES = ['reject', 'strip'] as const;
 export type DaemonLockPolicy = (typeof DAEMON_LOCK_POLICIES)[number];
-const LEASE_BACKENDS = ['ios-simulator', 'ios-instance', 'android-instance'] as const;
+const LEASE_BACKENDS = ['ios-simulator', 'ios-instance', 'android-instance', 'harmonyos-instance'] as const;
 export type LeaseBackend = (typeof LEASE_BACKENDS)[number];
 const DAEMON_SERVER_MODES = ['socket', 'http', 'dual'] as const;
 export type DaemonServerMode = (typeof DAEMON_SERVER_MODES)[number];
@@ -271,7 +271,7 @@ function optionalEnum<T extends string>(
 export const daemonRuntimeSchema = schema<SessionRuntimeHints>((input, path) => {
   const record = expectObject(input, path);
   return {
-    platform: optionalEnum(record, 'platform', ['ios', 'android'] as const, path),
+    platform: optionalEnum(record, 'platform', ['ios', 'android', 'harmonyos'] as const, path),
     metroHost: optionalString(record, 'metroHost', path),
     metroPort: optionalInteger(record, 'metroPort', path),
     bundleUrl: optionalString(record, 'bundleUrl', path),
diff --git a/src/__tests__/remote-connection.test.ts b/src/__tests__/remote-connection.test.ts
index c97a819e4..216999ddf 100644
--- a/src/__tests__/remote-connection.test.ts
+++ b/src/__tests__/remote-connection.test.ts
@@ -34,7 +34,9 @@ import {
   materializeRemoteConnectionForCommand,
   CLOUD_WEBDRIVER_REMOTE_LEASE_TTL_MS,
   PROXY_REMOTE_LEASE_TTL_MS,
+  resolveRequestedLeaseBackend,
 } from '../cli/commands/connection-runtime.ts';
+
 import { stopMetroCompanion } from '../metro/client-metro-companion.ts';
 import { AppError } from '@agent-device/kernel/errors';
 import {
@@ -45,6 +47,15 @@ import {
 } from '../remote/remote-connection-state.ts';
 import type { AgentDeviceClient } from '../agent-device-client.ts';
 
+test('HarmonyOS platform resolves to its proxy lease backend', () => {
+  assert.equal(
+    resolveRequestedLeaseBackend(
+      forceConnectFlags({ stateDir: '/tmp/agent-device', remoteConfig: '/tmp/remote.json', platform: 'harmonyos' }),
+    ),
+    'harmonyos-instance',
+  );
+});
+
 afterEach(() => {
   vi.clearAllMocks();
   vi.restoreAllMocks();
diff --git a/src/cli/commands/connection-runtime.ts b/src/cli/commands/connection-runtime.ts
index eb6cc6e81..871aabd06 100644
--- a/src/cli/commands/connection-runtime.ts
+++ b/src/cli/commands/connection-runtime.ts
@@ -689,6 +689,7 @@ export function resolveRequestedLeaseBackend(flags: CliFlags): LeaseBackend | un
   if (flags.leaseBackend) return flags.leaseBackend;
   if (flags.platform === 'android') return 'android-instance';
   if (flags.platform === 'ios') return 'ios-instance';
+  if (flags.platform === 'harmonyos') return 'harmonyos-instance';
   return undefined;
 }
 
@@ -697,7 +698,7 @@ function requireRequestedLeaseBackend(flags: CliFlags, command: string): LeaseBa
   if (leaseBackend) return leaseBackend;
   throw new AppError(
     'INVALID_ARGS',
-    `${command} requires --platform ios|android or --lease-backend when the remote connection has not resolved a lease yet.`,
+    `${command} requires --platform ios|android|harmonyos or --lease-backend when the remote connection has not resolved a lease yet.`,
   );
 }
 
@@ -733,7 +734,11 @@ function isRuntimeCompatibleWithPlatform(
   runtime: SessionRuntimeHints,
   platform: CliFlags['platform'],
 ): boolean {
-  if (!runtime.platform || !platform || (platform !== 'ios' && platform !== 'android')) {
+  if (
+    !runtime.platform ||
+    !platform ||
+    (platform !== 'ios' && platform !== 'android' && platform !== 'harmonyos')
+  ) {
     return true;
   }
   return runtime.platform === platform;
@@ -931,6 +936,7 @@ function buildProxyDeviceKey(device: DeviceInfo): string {
 function leaseBackendForDevice(device: DeviceInfo): LeaseBackend | undefined {
   if (isIosFamily(device)) return 'ios-instance';
   if (device.platform === 'android') return 'android-instance';
+  if (device.platform === 'harmonyos') return 'harmonyos-instance';
   return undefined;
 }
 
diff --git a/src/commands/cli-grammar/flag-definitions-connection.ts b/src/commands/cli-grammar/flag-definitions-connection.ts
index c59893b4f..d2ab5cfd6 100644
--- a/src/commands/cli-grammar/flag-definitions-connection.ts
+++ b/src/commands/cli-grammar/flag-definitions-connection.ts
@@ -105,8 +105,8 @@ export const CONNECTION_FLAG_DEFINITIONS: readonly FlagDefinition[] = [
     key: 'leaseBackend',
     names: ['--lease-backend'],
     type: 'enum',
-    enumValues: ['ios-simulator', 'ios-instance', 'android-instance'],
-    usageLabel: '--lease-backend ios-simulator|ios-instance|android-instance',
+    enumValues: ['ios-simulator', 'ios-instance', 'android-instance', 'harmonyos-instance'],
+    usageLabel: '--lease-backend ios-simulator|ios-instance|android-instance|harmonyos-instance',
     usageDescription: 'Lease backend for remote tenant connection admission',
   },
   {
diff --git a/src/daemon/__tests__/lease-registry-scope.test.ts b/src/daemon/__tests__/lease-registry-scope.test.ts
index 1bb76af55..e89f0fc41 100644
--- a/src/daemon/__tests__/lease-registry-scope.test.ts
+++ b/src/daemon/__tests__/lease-registry-scope.test.ts
@@ -4,9 +4,14 @@ import {
   createLeaseTtlResolver,
   leaseDeviceBindingKey,
   normalizeAllocateLeaseRequest,
+  normalizeLeaseBackend,
 } from '../lease-registry-scope.ts';
 import { HUMAN_CONTROL_LEASE_REQUEST, HUMAN_CONTROL_SCOPE } from './human-control-fixtures.ts';
 
+test('normalizeLeaseBackend accepts HarmonyOS instance backend', () => {
+  assert.equal(normalizeLeaseBackend('harmonyos-instance'), 'harmonyos-instance');
+});
+
 test('allocation and human control share the exact contention identity', () => {
   const scope = normalizeAllocateLeaseRequest(HUMAN_CONTROL_LEASE_REQUEST);
   assert.equal(leaseDeviceBindingKey(scope), leaseDeviceBindingKey(HUMAN_CONTROL_SCOPE));
diff --git a/src/daemon/lease-registry-scope.ts b/src/daemon/lease-registry-scope.ts
index 614afd244..f3d6ca59e 100644
--- a/src/daemon/lease-registry-scope.ts
+++ b/src/daemon/lease-registry-scope.ts
@@ -133,7 +133,7 @@ export function normalizeRequiredLeaseId(raw: string | undefined): string {
 export function normalizeLeaseBackend(raw: string | undefined): LeaseBackend {
   const value = (raw ?? '').trim().toLowerCase();
   if (!value || value === 'ios-simulator') return 'ios-simulator';
-  if (value === 'ios-instance' || value === 'android-instance') return value;
+  if (value === 'ios-instance' || value === 'android-instance' || value === 'harmonyos-instance') return value;
   throw new AppError('INVALID_ARGS', `Unsupported lease backend: ${raw ?? ''}`);
 }
 
diff --git a/src/daemon/session-runtime.ts b/src/daemon/session-runtime.ts
index 52b68b84a..aaaf2dbf5 100644
--- a/src/daemon/session-runtime.ts
+++ b/src/daemon/session-runtime.ts
@@ -86,10 +86,10 @@ function normalizeRuntimePlatformInput(
   platform?: RuntimePlatform,
 ): RuntimePlatform | undefined {
   if (value === undefined) return platform;
-  if (value !== 'ios' && value !== 'android') {
+  if (value !== 'ios' && value !== 'android' && value !== 'harmonyos') {
     throw new AppError(
       'INVALID_ARGS',
-      `Invalid open runtime platform: ${String(value)}. Use "ios" or "android".`,
+      `Invalid open runtime platform: ${String(value)}. Use "ios", "android", or "harmonyos".`,
     );
   }
   if (platform && value !== platform) {
@@ -104,7 +104,7 @@ function normalizeRuntimePlatformInput(
 export function toRuntimePlatform(
   platform: CommandFlags['platform'] | DeviceInfo['platform'] | 'apple' | undefined,
 ): RuntimePlatform | undefined {
-  if (platform === 'ios' || platform === 'android') {
+  if (platform === 'ios' || platform === 'android' || platform === 'harmonyos') {
     return platform;
   }
   return undefined;
@@ -215,7 +215,7 @@ function resolveSessionRuntimeHints(
   if (runtime.platform && device && !deviceRuntimePlatform) {
     throw new AppError(
       'INVALID_ARGS',
-      `Session runtime hints are only supported on iOS and Android sessions, but session "${sessionName}" is bound to ${boundPlatform}.`,
+      `Session runtime hints are only supported on iOS, Android, and HarmonyOS sessions, but session "${sessionName}" is bound to ${boundPlatform}.`,
     );
   }
   if (runtime.platform && deviceRuntimePlatform && runtime.platform !== deviceRuntimePlatform) {
diff --git a/src/remote/remote-config-schema.ts b/src/remote/remote-config-schema.ts
index 6c33f206d..f3cfc2752 100644
--- a/src/remote/remote-config-schema.ts
+++ b/src/remote/remote-config-schema.ts
@@ -61,7 +61,7 @@ export const REMOTE_CONFIG_FIELD_SPECS = [
   {
     key: 'leaseBackend',
     type: 'enum',
-    enumValues: ['ios-simulator', 'ios-instance', 'android-instance'],
+    enumValues: ['ios-simulator', 'ios-instance', 'android-instance', 'harmonyos-instance'],
   },
   { key: 'platform', type: 'enum', enumValues: PLATFORM_SELECTORS },
   { key: 'target', type: 'enum', enumValues: ['mobile', 'tv', 'desktop'] },
diff --git a/test/wire-compat/ledger.json b/test/wire-compat/ledger.json
index 7667d5a13..dc53b63f9 100644
--- a/test/wire-compat/ledger.json
+++ b/test/wire-compat/ledger.json
@@ -18,16 +18,16 @@
     "packages/kernel/src/contracts.ts#DaemonResponseData": "sha256:f16e61b7f0ea8cdae82349508383af2f97a4c16c8aa21952d833094673f86afc",
     "packages/kernel/src/contracts.ts#JsonRpcId": "sha256:5a5fdff1cd85971214117d69a8278d0ecaf21a6fa3f4582155d9b3d9cad1fbd0",
     "packages/kernel/src/contracts.ts#JsonRpcRequestEnvelope": "sha256:d6328309fc4f8b310b88680181e46c802329de9b0e45682dd2e0f0c3e8d090e4",
-    "packages/kernel/src/contracts.ts#LEASE_BACKENDS": "sha256:9fb296dcfd56556e4dd020bcb40f3b70890b274600e634aa2c380d860b38c022",
+    "packages/kernel/src/contracts.ts#LEASE_BACKENDS": "sha256:6bec996666d1043a8d23e60d5b1e50ef9341909a02f19060a3132bb72dcc3155",
     "packages/kernel/src/contracts.ts#LeaseBackend": "sha256:dce397343cda82ce4e3e43b534b1f642cd37568ed304f4783caddc3524c1cae5",
     "packages/kernel/src/contracts.ts#RESPONSE_LEVELS": "sha256:cef29c3b56c299e35a7fee8058b90dc4a6f65a46a420e4f11f77c8ca7d0359c8",
     "packages/kernel/src/contracts.ts#ResponseCost": "sha256:2a44de54e8b5c886b36da1500e22d634ec7e12961d2c93b689d2b1aa8c15f186",
     "packages/kernel/src/contracts.ts#ResponseLevel": "sha256:c7329d28e745b5e69b86aa1a686befa314b98248afbe5e0e2d7d395f0d777f9b",
     "packages/kernel/src/contracts.ts#SESSION_ISOLATION_MODES": "sha256:3d4b3048e22bb0ceccc98cf8fd93a87a1a1e2dad96fa03cffff6d0ecedb58689",
     "packages/kernel/src/contracts.ts#SessionIsolationMode": "sha256:beea941fe57b000902da28af15a27aa18d0c957408209e3ec372fcf7f605fa7c",
-    "packages/kernel/src/contracts.ts#SessionRuntimeHints": "sha256:6b945688ad5ab68370ec001d962974e1397c39d47c6f7ca2a65b03f5ccdd91c6",
+    "packages/kernel/src/contracts.ts#SessionRuntimeHints": "sha256:7e055a99bc6adbb3efc37b0691055f5370f35f8b96ae6af73295ccce61e05dfe",
     "packages/kernel/src/contracts.ts#commandRpcParamsSchema": "sha256:d0ce05c236ce5b0b52631ab7b8a75d38859fbfba58cfb28dd3f9d84f2dba2c1f",
-    "packages/kernel/src/contracts.ts#daemonRuntimeSchema": "sha256:010c171164ce9516e1c1b00e89e698a11842ff9c3bac3f2e8e3814de7c8be78c",
+    "packages/kernel/src/contracts.ts#daemonRuntimeSchema": "sha256:859eabaf6679d117feb2b4873b6ac69731cc06989645080817d39c43a24deea5",
     "packages/kernel/src/contracts.ts#jsonRpcRequestSchema": "sha256:67e6b8a28b39a3883424a565ae7033c336dc2ea6b193e9b32bb98eb3e18dca7c",
     "packages/kernel/src/device.ts#PLATFORM_SELECTORS": "sha256:36e9da1cc660c0ddfb4cf52521f7f230341ff20e3ebda3405ba7c1799476c42d",
     "packages/kernel/src/device.ts#PlatformSelector": "sha256:61de3f003507ea2f53b396b0146c17670bf674a2db2132e19c462ca6c10cc8fd",
@@ -227,6 +227,21 @@
       "declaration": "src/daemon/client/daemon-client-rpc.ts#appErrorFromDaemonError",
       "digest": "sha256:ac4761006c71d93ccba9f8e37cbd4cf48283dbb22737c163dc9c1a878e154eea",
       "rationale": "#1862 client-side only: this rehydrates the new optional structured `cause` when present. Released daemons that omit it follow the unchanged path, and no request field or existing response field is narrowed."
+    },
+    {
+      "declaration": "packages/kernel/src/contracts.ts#LEASE_BACKENDS",
+      "digest": "sha256:6bec996666d1043a8d23e60d5b1e50ef9341909a02f19060a3132bb72dcc3155",
+      "rationale": "#2266 adds the additive harmonyos-instance lease backend literal. Protocol-2 peers ignore the new backend unless explicitly requested; existing iOS/Android values and payloads remain unchanged."
+    },
+    {
+      "declaration": "packages/kernel/src/contracts.ts#SessionRuntimeHints",
+      "digest": "sha256:7e055a99bc6adbb3efc37b0691055f5370f35f8b96ae6af73295ccce61e05dfe",
+      "rationale": "#2266 adds the optional HarmonyOS platform value to runtime hints. Existing iOS/Android hints retain their shape and released peers can ignore the additive value."
+    },
+    {
+      "declaration": "packages/kernel/src/contracts.ts#daemonRuntimeSchema",
+      "digest": "sha256:859eabaf6679d117feb2b4873b6ac69731cc06989645080817d39c43a24deea5",
+      "rationale": "#2266 broadens runtime-hint validation to accept the additive HarmonyOS platform value; existing protocol-2 runtime hints remain valid and unchanged."
     }
   ]
 }