MetaMask · sirtimid · Jul 21, 2026
@@ -150,6 +150,7 @@
 /packages/wallet/src/initialization/instances/address-book-controller/           @MetaMask/confirmations
 /packages/wallet/src/initialization/instances/approval-controller/               @MetaMask/confirmations
 /packages/wallet/src/initialization/instances/connectivity-controller/           @MetaMask/core-platform
+/packages/wallet/src/initialization/instances/gas-fee-controller/                @MetaMask/confirmations
 /packages/wallet/src/initialization/instances/keyring-controller/                @MetaMask/accounts-engineers @MetaMask/core-platform
 /packages/wallet/src/initialization/instances/passkey-controller/                @MetaMask/web3auth
 /packages/wallet/src/initialization/instances/remote-feature-flag-controller/    @MetaMask/extension-platform @MetaMask/mobile-platform @MetaMask/core-platform

diff --git a/README.md b/README.md
@@ -649,6 +649,7 @@ linkStyle default opacity:0.5
   wallet --> base_controller;
   wallet --> connectivity_controller;
   wallet --> controller_utils;
+  wallet --> gas_fee_controller;
   wallet --> keyring_controller;
   wallet --> messenger;
   wallet --> network_controller;

diff --git a/codeowners.ts b/codeowners.ts
@@ -160,6 +160,7 @@ const PACKAGES: Record<string, PackageInfo> = {
   },
   'gas-fee-controller': {
     teams: ['@MetaMask/confirmations'],
+    initializationPath: 'gas-fee-controller',
   },
   'gator-permissions-controller': {
     teams: ['@MetaMask/delegation'],

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Wire the `transactionController` slot in the daemon wallet's instance options, so the daemon runs the `TransactionController` with an explicit CLI-appropriate configuration (swaps processing disabled, no client hooks) rather than relying on the controller's implicit defaults ([#9509](https://github.com/MetaMask/core/pull/9509))
+- Wire the `gasFeeController` slot in the daemon wallet's instance options, passing `clientId: 'cli'` so the CLI identifies itself to the gas estimation API, now that `@metamask/wallet` requires this option ([#9527](https://github.com/MetaMask/core/pull/9527))
 - Add the `mm wallet unlock` command, which dispatches `KeyringController:submitPassword` over the daemon socket, allowing the keyring to be unlocked after a daemon start with no password or after a `mm daemon call KeyringController:setLocked` ([#8821](https://github.com/MetaMask/core/pull/8821))
 - Add the `mm daemon list` command, which prints the messenger actions the running daemon can dispatch via `daemon call`, enumerated from the live messenger so the list cannot drift from what `call` accepts ([#9339](https://github.com/MetaMask/core/pull/9339))
 - Add the `mm daemon` command suite (`start`, `stop`, `status`, `purge`, and `call`) for running the wallet daemon and dispatching messenger actions over its socket ([#9255](https://github.com/MetaMask/core/pull/9255))

@@ -103,6 +103,7 @@ describe('createWallet', () => {
     expect(
       instanceOptions.connectivityController.connectivityAdapter,
     ).toBeInstanceOf(AlwaysOnlineAdapter);
+    expect(instanceOptions.gasFeeController.clientId).toBe('cli');
     expect(instanceOptions.networkController.infuraProjectId).toBe(
       'test-infura-id',
     );

@@ -83,6 +83,11 @@ function buildInstanceOptions(
     connectivityController: {
       connectivityAdapter: new AlwaysOnlineAdapter(),
     },
+    gasFeeController: {
+      // Identifies the CLI to the gas estimation API via the `X-Client-Id`
+      // header.
+      clientId: 'cli',
+    },
     networkController: {
       infuraProjectId,
     },

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **BREAKING:** Wire `GasFeeController` into the default wallet initialization ([#9527](https://github.com/MetaMask/core/pull/9527))
+  - Adds a required `instanceOptions.gasFeeController` option whose `clientId` (sent as `X-Client-Id` to the gas API) is required, so every client identifies itself; all other fields are optional and fall back to platform-agnostic defaults.
 - **BREAKING** Wire `SeedlessOnboardingController` and `PasskeyController` into the default wallet initialization ([#9533](https://github.com/MetaMask/core/pull/9533))
 
 ### Changed

@@ -62,6 +62,7 @@
     "@metamask/browser-passworder": "^6.0.0",
     "@metamask/connectivity-controller": "^0.3.0",
     "@metamask/controller-utils": "^12.3.0",
+    "@metamask/gas-fee-controller": "^26.2.4",
     "@metamask/keyring-controller": "^27.1.0",
     "@metamask/messenger": "^2.0.0",
     "@metamask/network-controller": "^34.0.0",

@@ -29,6 +29,9 @@ async function setupWallet(): Promise<Wallet> {
       connectivityController: {
         connectivityAdapter: new AlwaysOnlineAdapter(),
       },
+      gasFeeController: {
+        clientId: 'test',
+      },
       networkController: {
         infuraProjectId: 'fake-infura-project-id',
       },
@@ -89,6 +92,9 @@ describe('Wallet', () => {
         connectivityController: {
           connectivityAdapter: new AlwaysOnlineAdapter(),
         },
+        gasFeeController: {
+          clientId: 'test',
+        },
         keyringController: {
           encryptor: new MockEncryptor(),
         },
@@ -141,6 +147,9 @@ describe('Wallet', () => {
         connectivityController: {
           connectivityAdapter: new AlwaysOnlineAdapter(),
         },
+        gasFeeController: {
+          clientId: 'test',
+        },
         networkController: {
           infuraProjectId: 'fake-infura-project-id',
         },
@@ -184,6 +193,9 @@ describe('Wallet', () => {
         connectivityController: {
           connectivityAdapter: new AlwaysOnlineAdapter(),
         },
+        gasFeeController: {
+          clientId: 'test',
+        },
         networkController: {
           infuraProjectId: 'fake-infura-project-id',
         },
@@ -294,6 +306,9 @@ describe('Wallet', () => {
           connectivityController: {
             connectivityAdapter: new AlwaysOnlineAdapter(),
           },
+          gasFeeController: {
+            clientId: 'test',
+          },
           networkController: {
             infuraProjectId: 'fake-infura-project-id',
           },
@@ -326,6 +341,9 @@ describe('Wallet', () => {
           connectivityController: {
             connectivityAdapter: new AlwaysOnlineAdapter(),
           },
+          gasFeeController: {
+            clientId: 'test',
+          },
           networkController: {
             infuraProjectId: 'fake-infura-project-id',
           },
@@ -366,6 +384,9 @@ describe('Wallet', () => {
           connectivityController: {
             connectivityAdapter: new AlwaysOnlineAdapter(),
           },
+          gasFeeController: {
+            clientId: 'test',
+          },
           networkController: {
             infuraProjectId: 'fake-infura-project-id',
           },
@@ -454,6 +475,9 @@ describe('Wallet', () => {
           connectivityController: {
             connectivityAdapter: new AlwaysOnlineAdapter(),
           },
+          gasFeeController: {
+            clientId: 'test',
+          },
           networkController: {
             infuraProjectId: 'fake-infura-project-id',
           },

@@ -0,0 +1,239 @@
+import { GasFeeController } from '@metamask/gas-fee-controller';
+import { Messenger } from '@metamask/messenger';
+import { InMemoryStorageAdapter } from '@metamask/storage-service';
+
+import type { WalletOptions } from '../../../types.js';
+import { Wallet } from '../../../Wallet.js';
+import { defaultConfigurations } from '../../defaults.js';
+import type {
+  DefaultActions,
+  DefaultEvents,
+  RootMessenger,
+} from '../../defaults.js';
+import { AlwaysOnlineAdapter } from '../connectivity-controller/always-online-adapter.js';
+import { gasFeeController } from './gas-fee-controller.js';
+
+const controllers: GasFeeController[] = [];
+const wallets: Wallet[] = [];
+
+const REMOTE_FEATURE_FLAG_OPTIONS = {
+  clientConfigApiService: {
+    fetchRemoteFeatureFlags: async (): Promise<{
+      remoteFeatureFlags: Record<string, boolean>;
+      cacheTimestamp: number;
+    }> => ({ remoteFeatureFlags: {}, cacheTimestamp: Date.now() }),
+  },
+};
+
+type ActionHandler = (...args: unknown[]) => unknown;
+
+type AnyMessenger = Messenger<string>;
+
+describe('gasFeeController', () => {
+  afterEach(async () => {
+    for (const controller of controllers.splice(0)) {
+      controller.destroy();
+    }
+
+    await Promise.all(wallets.splice(0).map((wallet) => wallet.destroy()));
+  });
+
+  it('is registered as a default initialization configuration', () => {
+    expect(Object.values(defaultConfigurations)).toContain(gasFeeController);
+  });
+
+  it('initializes a GasFeeController with default state', () => {
+    const rootMessenger = getRootMessenger();
+    const messenger = gasFeeController.getMessenger(rootMessenger);
+
+    const instance = gasFeeController.init({
+      state: undefined,
+      messenger,
+      options: { clientId: 'test' },
+    });
+    controllers.push(instance);
+
+    expect(instance).toBeInstanceOf(GasFeeController);
+    expect(rootMessenger.call('GasFeeController:getState')).toStrictEqual({
+      gasFeeEstimatesByChainId: {},
+      gasFeeEstimates: {},
+      estimatedGasFeeTimeBounds: {},
+      gasEstimateType: 'none',
+      nonRPCGasFeeApisDisabled: false,
+    });
+  });
+
+  it('is initialized by the default Wallet configuration', () => {
+    const wallet = new Wallet({
+      instanceOptions: getInstanceOptions(),
+    });
+    wallets.push(wallet);
+
+    expect(wallet.getInstance('GasFeeController')).toBeInstanceOf(
+      GasFeeController,
+    );
+  });
+
+  it('exposes GasFeeController:fetchGasFeeEstimates over the shared bus, resolving the TransactionController delegation', async () => {
+    // The messenger binds the method at construction, so spy on the prototype
+    // before building the wallet. This also avoids the real network fetch.
+    const fetchGasFeeEstimates = jest
+      .spyOn(GasFeeController.prototype, 'fetchGasFeeEstimates')
+      .mockResolvedValue({
+        gasFeeEstimatesByChainId: {},
+        gasFeeEstimates: {},
+        estimatedGasFeeTimeBounds: {},
+        gasEstimateType: 'none',
+        nonRPCGasFeeApisDisabled: false,
+      });
+
+    const wallet = new Wallet({
+      instanceOptions: getInstanceOptions(),
+    });
+    wallets.push(wallet);
+
+    await wallet.messenger.call('GasFeeController:fetchGasFeeEstimates');
+
+    expect(fetchGasFeeEstimates).toHaveBeenCalled();
+  });
+
+  it('forwards the provided state to the controller', () => {
+    const rootMessenger = getRootMessenger();
+    const messenger = gasFeeController.getMessenger(rootMessenger);
+
+    const instance = gasFeeController.init({
+      state: {
+        gasFeeEstimatesByChainId: {},
+        gasFeeEstimates: {},
+        estimatedGasFeeTimeBounds: {},
+        gasEstimateType: 'none',
+        nonRPCGasFeeApisDisabled: true,
+      },
+      messenger,
+      options: { clientId: 'test' },
+    });
+    controllers.push(instance);
+
+    expect(instance.state.nonRPCGasFeeApisDisabled).toBe(true);
+  });
+
+  it('builds the network callbacks from the wired NetworkController', async () => {
+    const rootMessenger = getRootMessenger();
+    const messenger = gasFeeController.getMessenger(rootMessenger);
+
+    const instance = gasFeeController.init({
+      state: undefined,
+      messenger,
+      options: { clientId: 'test' },
+    });
+    controllers.push(instance);
+
+    // Drives `getProvider` and the EIP-1559/legacy/account callbacks; the
+    // estimate then fails at the offline provider, which is irrelevant here.
+    await expect(instance.fetchGasFeeEstimates()).rejects.toThrow(
+      'Gas fee/price estimation failed',
+    );
+  });
+
+  it('applies injectable options over the defaults', () => {
+    const rootMessenger = getRootMessenger();
+    const messenger = gasFeeController.getMessenger(rootMessenger);
+    const getCurrentAccountEIP1559Compatibility = jest
+      .fn()
+      .mockReturnValue(false);
+    const getCurrentNetworkLegacyGasAPICompatibility = jest
+      .fn()
+      .mockReturnValue(true);
+
+    const instance = gasFeeController.init({
+      state: undefined,
+      messenger,
+      options: {
+        EIP1559APIEndpoint: 'https://example.test/<chain_id>/eip1559',
+        legacyAPIEndpoint: 'https://example.test/<chain_id>/legacy',
+        clientId: 'test-client',
+        interval: 30_000,
+        getCurrentAccountEIP1559Compatibility,
+        getCurrentNetworkLegacyGasAPICompatibility,
+      },
+    });
+    controllers.push(instance);
+
+    expect(instance).toBeInstanceOf(GasFeeController);
+  });
+});
+
+function getRootMessenger(): RootMessenger<DefaultActions, DefaultEvents> {
+  const rootMessenger = new Messenger<'Root', DefaultActions, DefaultEvents>({
+    namespace: 'Root',
+  });
+
+  registerActionHandler(
+    rootMessenger,
+    'NetworkController',
+    'NetworkController:getState',
+    jest.fn().mockReturnValue({ selectedNetworkClientId: 'mainnet' }),
+  );
+
+  registerActionHandler(
+    rootMessenger,
+    'NetworkController',
+    'NetworkController:getNetworkClientById',
+    jest.fn().mockReturnValue({
+      // Errors immediately so `eth_gasPrice` fallback settles without a network
+      // call rather than hanging.
+      provider: {
+        sendAsync: (_request: unknown, callback: (error: Error) => void) =>
+          callback(new Error('offline')),
+      },
+      configuration: { chainId: '0x1' },
+    }),
+  );
+
+  registerActionHandler(
+    rootMessenger,
+    'NetworkController',
+    'NetworkController:getEIP1559Compatibility',
+    // `false` skips the EIP-1559/legacy API fetches, so a fetch goes straight to
+    // the offline provider above.
+    jest.fn().mockResolvedValue(false),
+  );
+
+  return rootMessenger;
+}
+
+function getInstanceOptions(): WalletOptions['instanceOptions'] {
+  return {
+    connectivityController: {
+      connectivityAdapter: new AlwaysOnlineAdapter(),
+    },
+    gasFeeController: {
+      clientId: 'test',
+    },
+    networkController: {
+      infuraProjectId: 'test-infura-project-id',
+    },
+    storageService: {
+      storage: new InMemoryStorageAdapter(),
+    },
+    remoteFeatureFlagController: REMOTE_FEATURE_FLAG_OPTIONS,
+  };
+}
+
+function registerActionHandler(
+  parent: RootMessenger<DefaultActions, DefaultEvents>,
+  namespace: string,
+  actionType: string,
+  handler: ActionHandler,
+): void {
+  const messenger = new Messenger({
+    namespace,
+    parent: parent as unknown as AnyMessenger,
+  });
+
+  (
+    messenger as unknown as {
+      registerActionHandler(type: string, handler: ActionHandler): void;
+    }
+  ).registerActionHandler(actionType, handler);
+}