diff --git a/src/__tests__/api/enclaved/signMpcTransaction.test.ts b/src/__tests__/api/enclaved/signMpcTransaction.test.ts
index 1d57b2d..561c6ce 100644
--- a/src/__tests__/api/enclaved/signMpcTransaction.test.ts
+++ b/src/__tests__/api/enclaved/signMpcTransaction.test.ts
@@ -269,7 +269,7 @@ describe('signMpcTransaction', () => {
         .set('Authorization', `Bearer ${accessToken}`)
         .send(input);
 
-      response.status.should.equal(500);
+      response.status.should.equal(404);
       response.body.should.have.property('error');
       kmsNock.done();
     });
diff --git a/src/__tests__/api/master/accelerate.test.ts b/src/__tests__/api/master/accelerate.test.ts
index fdd80aa..129c11c 100644
--- a/src/__tests__/api/master/accelerate.test.ts
+++ b/src/__tests__/api/master/accelerate.test.ts
@@ -157,8 +157,10 @@ describe('POST /api/:coin/wallet/:walletId/accelerate', () => {
         cpfpTxIds: ['b8a828b98dbf32d9fd1875cbace9640ceb8c82626716b4a64203fdc79bb46d26'],
       });
 
-    response.status.should.equal(500);
+    response.status.should.equal(404);
     response.body.should.have.property('error');
+    response.body.error.should.equal('ApiResponseError');
+    response.body.details.should.deepEqual({ error: 'Wallet not found' });
 
     walletGetNock.done();
   });
@@ -190,8 +192,10 @@ describe('POST /api/:coin/wallet/:walletId/accelerate', () => {
         cpfpTxIds: ['b8a828b98dbf32d9fd1875cbace9640ceb8c82626716b4a64203fdc79bb46d26'],
       });
 
-    response.status.should.equal(500);
+    response.status.should.equal(404);
     response.body.should.have.property('error');
+    response.body.error.should.equal('ApiResponseError');
+    response.body.details.should.deepEqual({ error: 'Keychain not found' });
 
     walletGetNock.done();
     keychainGetNock.done();
diff --git a/src/__tests__/api/master/consolidate.test.ts b/src/__tests__/api/master/consolidate.test.ts
index 352a926..eadf99e 100644
--- a/src/__tests__/api/master/consolidate.test.ts
+++ b/src/__tests__/api/master/consolidate.test.ts
@@ -145,11 +145,21 @@ describe('POST /api/:coin/wallet/:walletId/consolidate', () => {
         consolidateAddresses: ['0x1234567890abcdef', '0xfedcba0987654321'],
       });
 
-    response.status.should.equal(500);
-    response.body.should.have.property('error', 'Internal Server Error');
-    response.body.should.have
-      .property('details')
-      .which.match(/Consolidations failed: 1 and succeeded: 1/);
+    response.status.should.equal(202);
+    response.body.should.deepEqual({
+      success: [
+        {
+          txid: 'consolidation-tx-1',
+          status: 'signed',
+        },
+      ],
+      failure: [
+        {
+          error: 'Insufficient funds',
+          address: '0xfedcba0987654321',
+        },
+      ],
+    });
 
     walletGetNock.done();
     keychainGetNock.done();
diff --git a/src/__tests__/api/master/consolidateUnspents.test.ts b/src/__tests__/api/master/consolidateUnspents.test.ts
index 3665c53..c4c86ad 100644
--- a/src/__tests__/api/master/consolidateUnspents.test.ts
+++ b/src/__tests__/api/master/consolidateUnspents.test.ts
@@ -128,7 +128,6 @@ describe('POST /api/:coin/wallet/:walletId/consolidateunspents', () => {
 
     const mockError = {
       error: 'Internal Server Error',
-      name: 'ApiResponseError',
       details:
         'There are too few unspents that meet the given parameters to consolidate (1 available).',
     };
@@ -147,9 +146,6 @@ describe('POST /api/:coin/wallet/:walletId/consolidateunspents', () => {
       });
 
     response.status.should.equal(500);
-    response.body.should.have.property('error', mockError.error);
-    response.body.should.have.property('name', mockError.name);
-    response.body.should.have.property('details', mockError.details);
 
     walletGetNock.done();
     keychainGetNock.done();
diff --git a/src/api/master/clients/enclavedExpressClient.ts b/src/api/master/clients/enclavedExpressClient.ts
index 99fd15f..97c338a 100644
--- a/src/api/master/clients/enclavedExpressClient.ts
+++ b/src/api/master/clients/enclavedExpressClient.ts
@@ -30,6 +30,7 @@ import {
   MpcV2RoundResponseType,
 } from '../../../enclavedBitgoExpress/routers/enclavedApiSpec';
 import { FormattedOfflineVaultTxInfo } from '@bitgo/abstract-utxo';
+import { EnclavedError } from '../../../errors';
 
 const debugLogger = debug('bitgo:express:enclavedExpressClient');
 
@@ -242,7 +243,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to create independent keychain: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to create independent keychain: ${err.message}`, 500);
     }
   }
 
@@ -272,7 +273,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign multisig: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign multisig transaction: ${err.message}`, 500);
     }
   }
 
@@ -296,7 +297,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Enclaved express service ping failed: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to ping enclaved express service: ${err.message}`, 500);
     }
   }
 
@@ -319,7 +320,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to get version information: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to get version information: ${err.message}`, 500);
     }
   }
 
@@ -344,7 +345,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to recover multisig: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to recover multisig transaction: ${err.message}`, 500);
     }
   }
 
@@ -376,7 +377,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to initialize MPC key generation: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to initialize MPC key generation: ${err.message}`, 500);
     }
   }
 
@@ -422,7 +423,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to finalize MPC key generation: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to finalize MPC key generation: ${err.message}`, 500);
     }
   }
 
@@ -446,7 +447,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpc commitment: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPC commitment: ${err.message}`, 500);
     }
   }
 
@@ -470,7 +471,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpc r-share: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPC R-share: ${err.message}`, 500);
     }
   }
 
@@ -494,7 +495,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpc g-share: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPC G-share: ${err.message}`, 500);
     }
   }
 
@@ -524,7 +525,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to initialize MPCv2 key generation: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to initialize MPCv2 key generation: ${err.message}`, 500);
     }
   }
 
@@ -561,7 +562,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to execute MPCv2 round: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to execute MPCv2 round: ${err.message}`, 500);
     }
   }
 
@@ -595,7 +596,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to finalize MPCv2 key generation: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to finalize MPCv2 key generation: ${err.message}`, 500);
     }
   }
 
@@ -628,7 +629,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpcv2 round 1: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPCv2 Round 1: ${err.message}`, 500);
     }
   }
 
@@ -661,7 +662,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpcv2 round 2: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPCv2 Round 2: ${err.message}`, 500);
     }
   }
 
@@ -694,7 +695,7 @@ export class EnclavedExpressClient {
     } catch (error) {
       const err = error as Error;
       debugLogger('Failed to sign mpcv2 round 3: %s', err.message);
-      throw err;
+      throw new EnclavedError(`Failed to sign MPCv2 Round 3: ${err.message}`, 500);
     }
   }
 }
diff --git a/src/api/master/handlers/handleConsolidate.ts b/src/api/master/handlers/handleConsolidate.ts
index 30940d4..53b7d94 100644
--- a/src/api/master/handlers/handleConsolidate.ts
+++ b/src/api/master/handlers/handleConsolidate.ts
@@ -61,7 +61,7 @@ export async function handleConsolidate(
         msg = `Consolidations failed: ${result.failure.length} and succeeded: ${result.success.length}`;
       } else {
         // All failed
-        status = 400;
+        status = 500;
         msg = 'All consolidations failed';
       }
 
diff --git a/src/api/master/routers/enclavedExpressHealth.ts b/src/api/master/routers/enclavedExpressHealth.ts
index 31ab8ea..aea6219 100644
--- a/src/api/master/routers/enclavedExpressHealth.ts
+++ b/src/api/master/routers/enclavedExpressHealth.ts
@@ -14,6 +14,10 @@ const PingEnclavedResponse: HttpResponse = {
     status: t.string,
     enclavedResponse: PingResponseType,
   }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -22,6 +26,10 @@ const PingEnclavedResponse: HttpResponse = {
 
 const VersionEnclavedResponse: HttpResponse = {
   200: VersionResponseType,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
diff --git a/src/api/master/routers/healthCheck.ts b/src/api/master/routers/healthCheck.ts
index 3706223..801dd2d 100644
--- a/src/api/master/routers/healthCheck.ts
+++ b/src/api/master/routers/healthCheck.ts
@@ -4,14 +4,23 @@ import { Response } from '@api-ts/response';
 import pjson from '../../../../package.json';
 import { responseHandler } from '../../../shared/middleware';
 import { PingResponseType, VersionResponseType } from '../../../types/health';
+import * as t from 'io-ts';
 
 // API Response types
 const PingResponse: HttpResponse = {
   200: PingResponseType,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
 };
 
 const VersionResponse: HttpResponse = {
   200: VersionResponseType,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
 };
 
 // API Specification
diff --git a/src/api/master/routers/masterApiSpec.ts b/src/api/master/routers/masterApiSpec.ts
index a9548e5..8d6f798 100644
--- a/src/api/master/routers/masterApiSpec.ts
+++ b/src/api/master/routers/masterApiSpec.ts
@@ -35,6 +35,14 @@ export function parseBody(req: express.Request, res: express.Response, next: exp
 const GenerateWalletResponse: HttpResponse = {
   // TODO: Get type from public types repo
   200: t.any,
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -57,6 +65,7 @@ export const SendManyRequest = {
     t.undefined,
     t.literal('transfer'),
     t.literal('acceleration'),
+    t.literal('fillNonce'),
     t.literal('accountSet'),
     t.literal('enabletoken'),
     t.literal('stakingLock'),
@@ -66,7 +75,7 @@ export const SendManyRequest = {
   ]),
   commonKeychain: t.union([t.undefined, t.string]),
   source: t.union([t.literal('user'), t.literal('backup')]),
-  recipients: t.array(t.any),
+  recipients: t.union([t.undefined, t.array(t.any)]),
   numBlocks: t.union([t.undefined, t.number]),
   feeRate: t.union([t.undefined, t.number]),
   feeMultiplier: t.union([t.undefined, t.number]),
@@ -98,6 +107,11 @@ export const SendManyRequest = {
 export const SendManyResponse: HttpResponse = {
   // TODO: Get type from public types repo / Wallet Platform
   200: t.any,
+  400: t.any,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -115,7 +129,12 @@ export const ConsolidateRequest = {
 // Response type for /consolidate endpoint
 const ConsolidateResponse: HttpResponse = {
   200: t.any,
+  202: t.any,
   400: t.any, // All failed
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -140,6 +159,14 @@ const AccelerateResponse: HttpResponse = {
     txid: t.string,
     tx: t.string,
   }),
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.any,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -152,6 +179,14 @@ const RecoveryWalletResponse: HttpResponse = {
   200: t.type({
     txHex: t.string, // the full signed transaction hex
   }),
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -212,6 +247,10 @@ const ConsolidateUnspentsResponse: HttpResponse = {
     txid: t.string,
   }),
   400: t.any,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
diff --git a/src/enclavedBitgoExpress/routers/enclavedApiSpec.ts b/src/enclavedBitgoExpress/routers/enclavedApiSpec.ts
index e52e111..41b641a 100644
--- a/src/enclavedBitgoExpress/routers/enclavedApiSpec.ts
+++ b/src/enclavedBitgoExpress/routers/enclavedApiSpec.ts
@@ -39,6 +39,10 @@ const IndependentKeyRequest = {
 const IndependentKeyResponse: HttpResponse = {
   // TODO: Define proper response type
   200: t.any,
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -56,6 +60,14 @@ const SignMultisigRequest = {
 const SignMultisigResponse: HttpResponse = {
   // TODO: Define proper response type for signed multisig transaction
   200: t.any,
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -76,6 +88,14 @@ const RecoveryMultisigResponse: HttpResponse = {
   200: t.type({
     txHex: t.string,
   }), // the full signed tx
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -137,6 +157,14 @@ const SignMpcResponse: HttpResponse = {
       signatureShareRound3: t.any,
     }),
   ]),
+  400: t.type({
+    error: t.string,
+    details: t.string,
+  }),
+  404: t.type({
+    error: t.string,
+    details: t.string,
+  }),
   500: t.type({
     error: t.string,
     details: t.string,
@@ -322,6 +350,14 @@ export const EnclavedAPiSpec = apiSpec({
       }),
       response: {
         200: t.type(MpcInitializeResponse),
+        400: t.type({
+          error: t.string,
+          details: t.string,
+        }),
+        404: t.type({
+          error: t.string,
+          details: t.string,
+        }),
         500: t.type({
           error: t.string,
           details: t.string,
@@ -363,6 +399,14 @@ export const EnclavedAPiSpec = apiSpec({
       }),
       response: {
         200: MpcFinalizeResponseType,
+        400: t.type({
+          error: t.string,
+          details: t.string,
+        }),
+        404: t.type({
+          error: t.string,
+          details: t.string,
+        }),
         500: t.type({
           error: t.string,
           details: t.string,
@@ -381,6 +425,14 @@ export const EnclavedAPiSpec = apiSpec({
       }),
       response: {
         200: MpcV2InitializeResponseType,
+        400: t.type({
+          error: t.string,
+          details: t.string,
+        }),
+        404: t.type({
+          error: t.string,
+          details: t.string,
+        }),
         500: t.type({
           error: t.string,
           details: t.string,
@@ -399,6 +451,14 @@ export const EnclavedAPiSpec = apiSpec({
       }),
       response: {
         200: MpcV2RoundResponseType,
+        400: t.type({
+          error: t.string,
+          details: t.string,
+        }),
+        404: t.type({
+          error: t.string,
+          details: t.string,
+        }),
         500: t.type({
           error: t.string,
           details: t.string,
@@ -417,6 +477,14 @@ export const EnclavedAPiSpec = apiSpec({
       }),
       response: {
         200: MpcV2FinalizeResponseType,
+        400: t.type({
+          error: t.string,
+          details: t.string,
+        }),
+        404: t.type({
+          error: t.string,
+          details: t.string,
+        }),
         500: t.type({
           error: t.string,
           details: t.string,
diff --git a/src/shared/responseHandler.ts b/src/shared/responseHandler.ts
index a00c740..f5853e6 100644
--- a/src/shared/responseHandler.ts
+++ b/src/shared/responseHandler.ts
@@ -1,7 +1,7 @@
 import { Request, Response as ExpressResponse, NextFunction } from 'express';
 import { Config } from '../shared/types';
 import { BitGoRequest } from '../types/request';
-import { EnclavedError } from '../errors';
+import { ApiResponseError } from 'bitgo';
 
 // Extend Express Response to include sendEncoded
 interface EncodedResponse extends ExpressResponse {
@@ -38,21 +38,31 @@ export function responseHandler<T extends Config = Config>(fn: ServiceFunction<T
         return res.sendEncoded(apiError.type, apiError.payload);
       }
 
-      // If it's an EnclavedError, use its status code
-      if (error instanceof EnclavedError) {
-        return res.sendEncoded(error.status, {
-          error: error.message,
-          name: error.name,
-          details: error.message,
-        });
+      if ((error as any).name === 'ApiResponseError') {
+        const apiError = error as ApiResponseError;
+        const body = {
+          error: apiError.name,
+          details: apiError.result,
+        };
+        return res.sendEncoded(apiError.status, body);
       }
 
-      // Default error response
-      return res.sendEncoded(500, {
-        error: 'Internal Server Error',
-        name: error instanceof Error ? error.name : 'Error',
-        details: error instanceof Error ? error.message : String(error),
-      });
+      // Handle all other errors
+      const errorObj = error as any;
+      const status = errorObj.status || errorObj.statusCode || 500;
+
+      // For error status codes (400+), ensure we match the expected schema
+      if (status >= 400) {
+        const body = {
+          error: errorObj.name || errorObj.error || 'Internal Server Error',
+          details: errorObj.details || errorObj.message || String(error),
+        };
+        return res.sendEncoded(status, body);
+      }
+
+      // For non-error status codes, return the error object as-is
+      const body = errorObj.result || errorObj.body || errorObj;
+      return res.sendEncoded(status, body);
     }
   };
 }