diff --git a/yarn-project/cli-wallet/src/utils/wallet.ts b/yarn-project/cli-wallet/src/utils/wallet.ts
index 7f7eabc5949c..dbdcca8a8e91 100644
--- a/yarn-project/cli-wallet/src/utils/wallet.ts
+++ b/yarn-project/cli-wallet/src/utils/wallet.ts
@@ -311,7 +311,7 @@ export class CLIWallet extends BaseWallet {
     opts: SimulateViaEntrypointOptions,
   ): Promise<TxSimulationResultWithAppOffset> {
     const { from, feeOptions, additionalScopes, sendMessagesAs } = opts;
-    const scopes = this.scopesFrom(from, additionalScopes);
+    const scopes = this.scopesFrom(from, additionalScopes, sendMessagesAs);
     const feeExecutionPayload = await feeOptions.walletFeePaymentMethod?.getExecutionPayload();
     const finalExecutionPayload = feeExecutionPayload
       ? mergeExecutionPayloads([feeExecutionPayload, executionPayload])
diff --git a/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.test.ts b/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.test.ts
index 5d2de605b03d..c5d49775c8d4 100644
--- a/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.test.ts
+++ b/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.test.ts
@@ -80,6 +80,19 @@ describe('PrivateExecutionOracle', () => {
     });
   });
 
+  describe('getAppTaggingSecret', () => {
+    it('rejects a sender outside the execution scopes', async () => {
+      const inScopeSender = await AztecAddress.random();
+      const outOfScopeSender = await AztecAddress.random();
+      const recipient = await AztecAddress.random();
+      const oracle = makeOracle({ scopes: [inScopeSender] });
+
+      await expect(oracle.getAppTaggingSecret(outOfScopeSender, recipient)).rejects.toThrow(
+        'is not in the allowed scopes list',
+      );
+    });
+  });
+
   describe('resolveTaggingStrategy', () => {
     let sender: AztecAddress;
     let recipient: AztecAddress;
diff --git a/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.ts b/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.ts
index 481d28bc24c5..43642589f3f9 100644
--- a/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.ts
+++ b/yarn-project/pxe/src/contract_function_simulator/oracle/private_execution_oracle.ts
@@ -36,6 +36,7 @@ import {
   type TaggingSecretStrategy,
 } from '../../hooks/resolve_tagging_secret_strategy.js';
 import { NoteService } from '../../notes/note_service.js';
+import { assertAllowedScope } from '../../storage/allowed_scopes.js';
 import type { SenderTaggingStore } from '../../storage/tagging_store/sender_tagging_store.js';
 import { syncSenderTaggingIndexes } from '../../tagging/index.js';
 import type { ExecutionNoteCache } from '../execution_note_cache.js';
@@ -321,7 +322,17 @@ export class PrivateExecutionOracle extends UtilityExecutionOracle implements IP
    * @returns The app tagging secret, or `None` if the recipient is invalid.
    */
   public async getAppTaggingSecret(sender: AztecAddress, recipient: AztecAddress): Promise<Option<Fr>> {
-    const extendedSecret = await this.#calculateAppTaggingSecret(this.contractAddress, sender, recipient);
+    assertAllowedScope(sender, this.scopes);
+
+    const senderCompleteAddress = await this.getCompleteAddressOrFail(sender);
+    const senderIvsk = await this.keyStore.getMasterIncomingViewingSecretKey(sender);
+    const extendedSecret = await AppTaggingSecret.computeViaEcdh(
+      senderCompleteAddress,
+      senderIvsk,
+      recipient,
+      this.contractAddress,
+      recipient,
+    );
 
     if (!extendedSecret) {
       this.logger.warn(`Computing a tagging secret for invalid recipient ${recipient} - returning no secret`, {
@@ -354,12 +365,6 @@ export class PrivateExecutionOracle extends UtilityExecutionOracle implements IP
     return index;
   }
 
-  async #calculateAppTaggingSecret(contractAddress: AztecAddress, sender: AztecAddress, recipient: AztecAddress) {
-    const senderCompleteAddress = await this.getCompleteAddressOrFail(sender);
-    const senderIvsk = await this.keyStore.getMasterIncomingViewingSecretKey(sender);
-    return AppTaggingSecret.computeViaEcdh(senderCompleteAddress, senderIvsk, recipient, contractAddress, recipient);
-  }
-
   async #getIndexToUseForSecret(secret: AppTaggingSecret): Promise<number> {
     // If we have the tagging index in the cache, we use it. If not we obtain it from the execution data provider.
     const lastUsedIndexInTx = this.taggingIndexCache.getLastUsedIndex(secret);
diff --git a/yarn-project/wallet-sdk/src/base-wallet/base_wallet.ts b/yarn-project/wallet-sdk/src/base-wallet/base_wallet.ts
index 8ddf690bbb3e..afef9c61238b 100644
--- a/yarn-project/wallet-sdk/src/base-wallet/base_wallet.ts
+++ b/yarn-project/wallet-sdk/src/base-wallet/base_wallet.ts
@@ -125,8 +125,15 @@ export abstract class BaseWallet implements Wallet {
     protected log = createLogger('wallet-sdk:base_wallet'),
   ) {}
 
-  protected scopesFrom(from: AztecAddress | NoFrom, additionalScopes: AztecAddress[] = []): AztecAddress[] {
-    const allScopes = from === NO_FROM ? additionalScopes : [from, ...additionalScopes];
+  protected scopesFrom(
+    from: AztecAddress | NoFrom,
+    additionalScopes: AztecAddress[] = [],
+    sendMessagesAs?: AztecAddress,
+  ): AztecAddress[] {
+    // The sendMessageAs account must be in scope so that its tagging secrets can be accessed.
+    const tagSenderScopes = sendMessagesAs ? [sendMessagesAs] : [];
+    const baseScopes = from === NO_FROM ? [] : [from];
+    const allScopes = [...baseScopes, ...additionalScopes, ...tagSenderScopes];
     const scopeSet = new Set(allScopes.map(address => address.toString()));
     return [...scopeSet].map(AztecAddress.fromStringUnsafe);
   }
@@ -402,7 +409,7 @@ export abstract class BaseWallet implements Wallet {
       simulatePublic: true,
       skipTxValidation: opts.skipTxValidation,
       skipFeeEnforcement: opts.skipFeeEnforcement,
-      scopes: this.scopesFrom(opts.from, opts.additionalScopes),
+      scopes: this.scopesFrom(opts.from, opts.additionalScopes, opts.sendMessagesAs),
       senderForTags: this.senderForTagsFrom(opts.from, opts.sendMessagesAs),
       overrides: opts.overrides,
     });
@@ -498,7 +505,7 @@ export abstract class BaseWallet implements Wallet {
     return this.pxe.profileTx(txRequest, {
       profileMode: opts.profileMode,
       skipProofGeneration: opts.skipProofGeneration ?? true,
-      scopes: this.scopesFrom(opts.from, opts.additionalScopes),
+      scopes: this.scopesFrom(opts.from, opts.additionalScopes, opts.sendMessagesAs),
       senderForTags: this.senderForTagsFrom(opts.from, opts.sendMessagesAs),
     });
   }
@@ -515,7 +522,7 @@ export abstract class BaseWallet implements Wallet {
     });
     const txRequest = await this.createTxExecutionRequestFromPayloadAndFee(executionPayload, opts.from, feeOptions);
     const provenTx = await this.pxe.proveTx(txRequest, {
-      scopes: this.scopesFrom(opts.from, opts.additionalScopes),
+      scopes: this.scopesFrom(opts.from, opts.additionalScopes, opts.sendMessagesAs),
       senderForTags: this.senderForTagsFrom(opts.from, opts.sendMessagesAs),
     });
     const offchainOutput = extractOffchainOutput(
diff --git a/yarn-project/wallets/src/embedded/embedded_wallet.test.ts b/yarn-project/wallets/src/embedded/embedded_wallet.test.ts
index e91818763460..cea4feec1f14 100644
--- a/yarn-project/wallets/src/embedded/embedded_wallet.test.ts
+++ b/yarn-project/wallets/src/embedded/embedded_wallet.test.ts
@@ -42,7 +42,7 @@ describe('EmbeddedWallet', () => {
   });
 
   describe('sendTx', () => {
-    it('passes sendMessagesAs as senderForTags to PXE simulation', async () => {
+    it('passes sendMessagesAs as senderForTags and includes it in scopes for PXE simulation', async () => {
       getPredictedMinFees.mockResolvedValue([new GasFees(2, 2)]);
       getNodeInfo.mockResolvedValue({
         l1ChainId: 1,
@@ -69,7 +69,10 @@ describe('EmbeddedWallet', () => {
 
       expect(simulateTx).toHaveBeenCalledWith(
         expect.anything(),
-        expect.objectContaining({ senderForTags: sendMessagesAs }),
+        expect.objectContaining({
+          senderForTags: sendMessagesAs,
+          scopes: expect.arrayContaining([sendMessagesAs]),
+        }),
       );
     });
 
diff --git a/yarn-project/wallets/src/embedded/embedded_wallet.ts b/yarn-project/wallets/src/embedded/embedded_wallet.ts
index 84843021e08c..42b2080e628a 100644
--- a/yarn-project/wallets/src/embedded/embedded_wallet.ts
+++ b/yarn-project/wallets/src/embedded/embedded_wallet.ts
@@ -329,7 +329,7 @@ export class EmbeddedWallet extends BaseWallet {
     opts: SimulateViaEntrypointOptions,
   ): Promise<TxSimulationResultWithAppOffset> {
     const { from, feeOptions, additionalScopes, skipTxValidation, skipFeeEnforcement, sendMessagesAs } = opts;
-    const scopes = this.scopesFrom(from, additionalScopes);
+    const scopes = this.scopesFrom(from, additionalScopes, sendMessagesAs);
 
     const feeExecutionPayload = await feeOptions.walletFeePaymentMethod?.getExecutionPayload();
     const finalExecutionPayload = feeExecutionPayload