diff --git a/src/modules/first-leg/api/customs.test.mjs b/src/modules/first-leg/api/customs.test.mjs
index 1178ea2..2e780ee 100644
--- a/src/modules/first-leg/api/customs.test.mjs
+++ b/src/modules/first-leg/api/customs.test.mjs
@@ -12,6 +12,8 @@ test('maps only the frozen merchant container-customs contract', () => {
   assert.match(source, /orderId: string/)
   assert.match(source, /documentId: string/)
   assert.match(source, /loadingPlanId: string/)
+  assert.match(source, /getMerchantCustomsForOrder\(orderId: string\)/)
+  assert.doesNotMatch(source, /number \| string/)
   assert.match(source, /url: `\/merchant\/v1\/customs\/orders\/\$\{encodedId\(orderId\)\}`/)
   assert.doesNotMatch(source, /customs\/cases|MerchantCustomsCaseDetail|getMerchantCustomsByOrder/)
 })
diff --git a/src/modules/first-leg/api/customs.ts b/src/modules/first-leg/api/customs.ts
index ea26674..6e7d15f 100644
--- a/src/modules/first-leg/api/customs.ts
+++ b/src/modules/first-leg/api/customs.ts
@@ -73,13 +73,13 @@ export const MERCHANT_CUSTOMS_STATUS_LABELS: Record<MerchantCustomsStatus, strin
 
 const MAX_CUSTOMS_FILE_SIZE = 50 * 1024 * 1024
 
-function encodedId(value: number | string) {
-  return encodeURIComponent(String(value))
+function encodedId(value: string) {
+  return encodeURIComponent(value)
 }
 
-function inboundQuery(inboundIds: Array<number | string>) {
+function inboundQuery(inboundIds: string[]) {
   const params = new URLSearchParams()
-  inboundIds.map(String).forEach((id) => params.append('inboundIds', id))
+  inboundIds.forEach((id) => params.append('inboundIds', id))
   return params.toString()
 }
 
@@ -93,14 +93,14 @@ export function validateMerchantCustomsFile(file: File) {
   if (file.size > MAX_CUSTOMS_FILE_SIZE) throw new Error('单个文件不能超过 50MB')
 }
 
-export function getMerchantCustomsForOrder(orderId: number | string) {
+export function getMerchantCustomsForOrder(orderId: string) {
   return apiRequest<MerchantCustomsContainer>({
     method: 'GET',
     url: `/merchant/v1/customs/orders/${encodedId(orderId)}`,
   })
 }
 
-export function uploadMerchantCustomsDocument(planId: number | string, inboundIds: Array<number | string>, file: File) {
+export function uploadMerchantCustomsDocument(planId: string, inboundIds: string[], file: File) {
   validateMerchantCustomsFile(file)
   return apiRequest<MerchantCustomsDocument>({
     method: 'POST',
@@ -111,7 +111,7 @@ export function uploadMerchantCustomsDocument(planId: number | string, inboundId
   })
 }
 
-export function replaceMerchantCustomsDocument(document: MerchantCustomsDocument, inboundIds: Array<number | string>, file: File) {
+export function replaceMerchantCustomsDocument(document: MerchantCustomsDocument, inboundIds: string[], file: File) {
   validateMerchantCustomsFile(file)
   const params = new URLSearchParams(inboundQuery(inboundIds))
   params.set('expectedVersion', String(document.source.version))
@@ -124,12 +124,12 @@ export function replaceMerchantCustomsDocument(document: MerchantCustomsDocument
   })
 }
 
-export function updateMerchantCustomsDocumentInbounds(document: MerchantCustomsDocument, inboundIds: Array<number | string>) {
+export function updateMerchantCustomsDocumentInbounds(document: MerchantCustomsDocument, inboundIds: string[]) {
   return apiRequest<MerchantCustomsDocument>({
     method: 'PUT',
     url: `/merchant/v1/customs/documents/${encodedId(document.documentId)}/inbounds`,
     headers: { 'Idempotency-Key': createIdempotencyKey(`merchant-customs-scope-${document.documentId}`) },
-    data: { inboundIds: inboundIds.map(String), expectedVersion: document.source.version },
+    data: { inboundIds, expectedVersion: document.source.version },
   })
 }
 
diff --git a/src/modules/first-leg/views/FirstLegOrdersView.test.mjs b/src/modules/first-leg/views/FirstLegOrdersView.test.mjs
index a74f1bd..b395768 100644
--- a/src/modules/first-leg/views/FirstLegOrdersView.test.mjs
+++ b/src/modules/first-leg/views/FirstLegOrdersView.test.mjs
@@ -512,7 +512,7 @@ test('supports the frozen customs document workflow and customer-safe downloads'
     '/completion/download',
   ]) assert.match(customsApiSource, new RegExp(path.replaceAll('/', '\\/')))
   assert.match(customsApiSource, /MAX_CUSTOMS_FILE_SIZE = 50 \* 1024 \* 1024/)
-  assert.match(customsApiSource, /inboundIds: inboundIds\.map\(String\)/)
+  assert.match(customsApiSource, /data: \{ inboundIds, expectedVersion: document\.source\.version \}/)
   assert.match(customsApiSource, /requestId: error\.requestId/)
   assert.match(customsDialogSource, /报关开始后仅可查看和下载，不提供退回或解锁/)
   assert.match(customsDialogSource, /detail\.status === 'COMPLETED' && item\.completion/)