diff --git a/src/services/claudeRelayService.js b/src/services/claudeRelayService.js
index 78fba6f7..dab6824a 100644
--- a/src/services/claudeRelayService.js
+++ b/src/services/claudeRelayService.js
@@ -12,9 +12,7 @@ const claudeCodeHeadersService = require('./claudeCodeHeadersService')
 const redis = require('../models/redis')
 const ClaudeCodeValidator = require('../validators/clients/claudeCodeValidator')
 const { formatDateWithTimezone } = require('../utils/dateHelper')
-const runtimeAddon = require('../utils/runtimeAddon')
-
-const RUNTIME_EVENT_FMT_CLAUDE_REQ = 'fmtClaudeReq'
+const requestIdentityService = require('./requestIdentityService')
 
 class ClaudeRelayService {
   constructor() {
@@ -941,7 +939,7 @@ class ClaudeRelayService {
     return filteredHeaders
   }
 
-  _applyLocalRequestFormatters(body, headers, context = {}) {
+  _applyRequestIdentityTransform(body, headers, context = {}) {
     const normalizedHeaders = headers && typeof headers === 'object' ? { ...headers } : {}
 
     try {
@@ -951,7 +949,7 @@ class ClaudeRelayService {
         ...context
       }
 
-      const result = runtimeAddon.emitSync(RUNTIME_EVENT_FMT_CLAUDE_REQ, payload)
+      const result = requestIdentityService.transform(payload)
       if (!result || typeof result !== 'object') {
         return { body, headers: normalizedHeaders }
       }
@@ -966,7 +964,7 @@ class ClaudeRelayService {
 
       return { body: nextBody, headers: nextHeaders, abortResponse }
     } catch (error) {
-      logger.warn('⚠️ 应用本地 fmtClaudeReq 插件失败:', error)
+      logger.warn('⚠️ 应用请求身份转换失败:', error)
       return { body, headers: normalizedHeaders }
     }
   }
@@ -1012,7 +1010,7 @@ class ClaudeRelayService {
       })
     }
 
-    const extensionResult = this._applyLocalRequestFormatters(requestPayload, finalHeaders, {
+    const extensionResult = this._applyRequestIdentityTransform(requestPayload, finalHeaders, {
       account,
       accountId,
       clientHeaders,
@@ -1332,7 +1330,7 @@ class ClaudeRelayService {
       })
     }
 
-    const extensionResult = this._applyLocalRequestFormatters(requestPayload, finalHeaders, {
+    const extensionResult = this._applyRequestIdentityTransform(requestPayload, finalHeaders, {
       account,
       accountId,
       accountType,
diff --git a/src/services/requestIdentityService.js b/src/services/requestIdentityService.js
new file mode 100644
index 00000000..48d87450
--- /dev/null
+++ b/src/services/requestIdentityService.js
@@ -0,0 +1,416 @@
+/**
+ * Request Identity Service
+ *
+ * 处理 Claude 请求的身份信息规范化：
+ * 1. Stainless 指纹管理 - 收集、持久化和应用 x-stainless-* 系列请求头
+ * 2. User ID 规范化 - 重写 metadata.user_id，使其与真实账户保持一致
+ */
+
+const crypto = require('crypto')
+const logger = require('../utils/logger')
+const redisService = require('../models/redis')
+
+const SESSION_PREFIX = 'session_'
+const ACCOUNT_MARKER = '_account_'
+const STAINLESS_HEADER_KEYS = [
+  'x-stainless-retry-count',
+  'x-stainless-timeout',
+  'x-stainless-lang',
+  'x-stainless-package-version',
+  'x-stainless-os',
+  'x-stainless-arch',
+  'x-stainless-runtime',
+  'x-stainless-runtime-version'
+]
+const MIN_FINGERPRINT_FIELDS = 4
+const REDIS_KEY_PREFIX = 'fmt_claude_req:stainless_headers:'
+
+function formatUuidFromSeed(seed) {
+  const digest = crypto.createHash('sha256').update(String(seed)).digest()
+  const bytes = Buffer.from(digest.subarray(0, 16))
+
+  bytes[6] = (bytes[6] & 0x0f) | 0x40
+  bytes[8] = (bytes[8] & 0x3f) | 0x80
+
+  const hex = Array.from(bytes)
+    .map((byte) => byte.toString(16).padStart(2, '0'))
+    .join('')
+
+  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`
+}
+
+function safeParseJson(value) {
+  if (typeof value !== 'string' || !value.trim()) {
+    return null
+  }
+
+  try {
+    const parsed = JSON.parse(value)
+    return parsed && typeof parsed === 'object' ? parsed : null
+  } catch (error) {
+    return null
+  }
+}
+
+function getRedisClient() {
+  if (!redisService || typeof redisService.getClientSafe !== 'function') {
+    throw new Error('requestIdentityService: Redis 服务未初始化')
+  }
+
+  return redisService.getClientSafe()
+}
+
+function hasFingerprintValues(fingerprint) {
+  return fingerprint && typeof fingerprint === 'object' && Object.keys(fingerprint).length > 0
+}
+
+function sanitizeFingerprint(source) {
+  if (!source || typeof source !== 'object') {
+    return {}
+  }
+
+  const normalized = {}
+  const lowerCaseSource = {}
+
+  Object.keys(source).forEach((key) => {
+    const value = source[key]
+    if (value === undefined || value === null || String(value).trim() === '') {
+      return
+    }
+    lowerCaseSource[key.toLowerCase()] = String(value)
+  })
+
+  STAINLESS_HEADER_KEYS.forEach((key) => {
+    if (lowerCaseSource[key]) {
+      normalized[key] = lowerCaseSource[key]
+    }
+  })
+
+  return normalized
+}
+
+function collectFingerprintFromHeaders(headers) {
+  if (!headers || typeof headers !== 'object') {
+    return {}
+  }
+
+  const subset = {}
+
+  Object.keys(headers).forEach((key) => {
+    const lowerKey = key.toLowerCase()
+    if (STAINLESS_HEADER_KEYS.includes(lowerKey)) {
+      subset[lowerKey] = headers[key]
+    }
+  })
+
+  return sanitizeFingerprint(subset)
+}
+
+function removeHeaderCaseInsensitive(target, key) {
+  if (!target || typeof target !== 'object') {
+    return
+  }
+
+  const lowerKey = key.toLowerCase()
+  Object.keys(target).forEach((candidate) => {
+    if (candidate.toLowerCase() === lowerKey) {
+      delete target[candidate]
+    }
+  })
+}
+
+function applyFingerprintToHeaders(headers, fingerprint) {
+  if (!headers || typeof headers !== 'object') {
+    return headers
+  }
+
+  if (!hasFingerprintValues(fingerprint)) {
+    return { ...headers }
+  }
+
+  const nextHeaders = { ...headers }
+
+  STAINLESS_HEADER_KEYS.forEach((key) => {
+    if (!Object.prototype.hasOwnProperty.call(fingerprint, key)) {
+      return
+    }
+    removeHeaderCaseInsensitive(nextHeaders, key)
+    nextHeaders[key] = fingerprint[key]
+  })
+
+  return nextHeaders
+}
+
+function persistFingerprint(accountId, fingerprint) {
+  if (!accountId || !hasFingerprintValues(fingerprint)) {
+    return
+  }
+
+  const client = getRedisClient()
+  const key = `${REDIS_KEY_PREFIX}${accountId}`
+  const serialized = JSON.stringify(fingerprint)
+
+  const command = client.set(key, serialized, 'NX')
+
+  if (command && typeof command.catch === 'function') {
+    command.catch((error) => {
+      logger.error(`requestIdentityService: Redis 持久化指纹失败 (${accountId}): ${error.message}`)
+    })
+  }
+}
+
+function getHeaderValueCaseInsensitive(headers, key) {
+  if (!headers || typeof headers !== 'object') {
+    return undefined
+  }
+
+  const lowerKey = key.toLowerCase()
+  for (const candidate of Object.keys(headers)) {
+    if (candidate.toLowerCase() === lowerKey) {
+      return headers[candidate]
+    }
+  }
+
+  return undefined
+}
+
+function headersChanged(original, updated) {
+  if (original === updated) {
+    return false
+  }
+
+  for (const key of STAINLESS_HEADER_KEYS) {
+    if (
+      getHeaderValueCaseInsensitive(original, key) !== getHeaderValueCaseInsensitive(updated, key)
+    ) {
+      return true
+    }
+  }
+
+  return false
+}
+
+function resolveAccountId(payload) {
+  if (!payload || typeof payload !== 'object') {
+    return null
+  }
+
+  const account = payload.account && typeof payload.account === 'object' ? payload.account : null
+  const candidates = [
+    payload.accountId,
+    payload.account_id,
+    payload.accountID,
+    account && (account.accountId || account.account_id || account.accountID),
+    account && (account.id || account.uuid),
+    account && (account.account_uuid || account.accountUuid),
+    account && (account.schedulerAccountId || account.scheduler_account_id)
+  ]
+
+  for (const candidate of candidates) {
+    if (candidate === undefined || candidate === null) {
+      continue
+    }
+
+    const stringified = String(candidate).trim()
+    if (stringified) {
+      return stringified
+    }
+  }
+
+  return null
+}
+
+function rewriteHeaders(headers, accountId) {
+  if (!headers || typeof headers !== 'object') {
+    return { nextHeaders: headers, changed: false }
+  }
+
+  if (!accountId) {
+    return { nextHeaders: { ...headers }, changed: false }
+  }
+
+  const workingHeaders = { ...headers }
+  const fingerprint = collectFingerprintFromHeaders(workingHeaders)
+  const fieldCount = Object.keys(fingerprint).length
+
+  if (fieldCount < MIN_FINGERPRINT_FIELDS) {
+    logger.warn(
+      `requestIdentityService: 账号 ${accountId} 提供的 Stainless 指纹字段不足，已保持原样`
+    )
+    return { nextHeaders: workingHeaders, changed: false }
+  }
+
+  try {
+    persistFingerprint(accountId, fingerprint)
+  } catch (error) {
+    logger.error(`requestIdentityService: 持久化指纹失败 (${accountId}): ${error.message}`)
+    return {
+      abortResponse: {
+        statusCode: 500,
+        headers: { 'content-type': 'application/json' },
+        body: JSON.stringify({ error: 'fingerprint_persist_failed', message: '指纹信息持久化失败' })
+      }
+    }
+  }
+
+  const appliedHeaders = applyFingerprintToHeaders(workingHeaders, fingerprint)
+  const changed = headersChanged(workingHeaders, appliedHeaders)
+
+  return { nextHeaders: appliedHeaders, changed }
+}
+
+function normalizeAccountUuid(candidate) {
+  if (typeof candidate !== 'string') {
+    return null
+  }
+
+  const trimmed = candidate.trim()
+  return trimmed || null
+}
+
+function extractAccountUuid(account) {
+  if (!account || typeof account !== 'object') {
+    return null
+  }
+
+  const extInfoRaw = account.extInfo
+  if (!extInfoRaw) {
+    return null
+  }
+
+  const extInfoObject = typeof extInfoRaw === 'string' ? safeParseJson(extInfoRaw) : null
+
+  if (!extInfoObject || typeof extInfoObject !== 'object') {
+    return null
+  }
+
+  const extUuid = normalizeAccountUuid(extInfoObject.account_uuid)
+  return extUuid || null
+}
+
+function rewriteUserId(body, accountId, accountUuid) {
+  if (!body || typeof body !== 'object') {
+    return { nextBody: body, changed: false }
+  }
+
+  const { metadata } = body
+  if (!metadata || typeof metadata !== 'object') {
+    return { nextBody: body, changed: false }
+  }
+
+  const userId = metadata.user_id
+  if (typeof userId !== 'string') {
+    return { nextBody: body, changed: false }
+  }
+
+  const pivot = userId.lastIndexOf(SESSION_PREFIX)
+  if (pivot === -1) {
+    return { nextBody: body, changed: false }
+  }
+
+  const prefixBeforeSession = userId.slice(0, pivot)
+  const sessionTail = userId.slice(pivot + SESSION_PREFIX.length)
+
+  const seedTail = sessionTail || 'default'
+  const effectiveScheduler = accountId ? String(accountId) : 'unknown-scheduler'
+  const hashed = formatUuidFromSeed(`${effectiveScheduler}::${seedTail}`)
+
+  let normalizedPrefix = prefixBeforeSession
+
+  if (accountUuid) {
+    const trimmedUuid = normalizeAccountUuid(accountUuid)
+    if (trimmedUuid) {
+      const accountIndex = normalizedPrefix.indexOf(ACCOUNT_MARKER)
+
+      if (accountIndex === -1) {
+        const base = normalizedPrefix.replace(/_+$/, '')
+        const baseWithMarker = /_account$/.test(base) ? base : `${base}_account`
+        normalizedPrefix = `${baseWithMarker}_${trimmedUuid}_`
+      } else {
+        const valueStart = accountIndex + ACCOUNT_MARKER.length
+        let separatorIndex = normalizedPrefix.indexOf('_', valueStart)
+        if (separatorIndex === -1) {
+          separatorIndex = normalizedPrefix.length
+        }
+
+        const head = normalizedPrefix.slice(0, valueStart)
+        let tail = '_'
+
+        if (separatorIndex < normalizedPrefix.length) {
+          tail = normalizedPrefix.slice(separatorIndex)
+          if (/^_+$/.test(tail)) {
+            tail = '_'
+          }
+        }
+
+        normalizedPrefix = `${head}${trimmedUuid}${tail}`
+      }
+    }
+  }
+
+  const nextUserId = `${normalizedPrefix}${SESSION_PREFIX}${hashed}`
+
+  if (nextUserId === userId) {
+    return { nextBody: body, changed: false }
+  }
+
+  const nextBody = {
+    ...body,
+    metadata: {
+      ...metadata,
+      user_id: nextUserId
+    }
+  }
+
+  return { nextBody, changed: true }
+}
+
+/**
+ * 转换请求身份信息
+ * @param {Object} payload - 请求载荷
+ * @param {Object} payload.body - 请求体
+ * @param {Object} payload.headers - 请求头
+ * @param {string} payload.accountId - 账户ID
+ * @param {Object} payload.account - 账户对象
+ * @returns {Object} 转换后的 { body, headers, abortResponse? }
+ */
+function transform(payload = {}) {
+  const currentBody = payload.body
+  const currentHeaders = payload.headers
+
+  if (!payload.accountId) {
+    return {
+      body: currentBody,
+      headers: currentHeaders
+    }
+  }
+
+  const accountUuid = extractAccountUuid(payload.account)
+  const accountIdForHeaders = resolveAccountId(payload)
+
+  const { nextBody } = rewriteUserId(currentBody, payload.accountId, accountUuid)
+  const headerResult = rewriteHeaders(currentHeaders, accountIdForHeaders)
+
+  const nextHeaders = headerResult ? headerResult.nextHeaders : currentHeaders
+  const abortResponse =
+    headerResult && headerResult.abortResponse ? headerResult.abortResponse : null
+
+  return {
+    body: nextBody,
+    headers: nextHeaders,
+    abortResponse
+  }
+}
+
+module.exports = {
+  transform,
+  // 导出内部函数供测试使用
+  _internal: {
+    formatUuidFromSeed,
+    collectFingerprintFromHeaders,
+    rewriteHeaders,
+    rewriteUserId,
+    extractAccountUuid,
+    resolveAccountId
+  }
+}
diff --git a/web/admin-spa/src/views/AccountsView.vue b/web/admin-spa/src/views/AccountsView.vue
index 5364b05e..4808c560 100644
--- a/web/admin-spa/src/views/AccountsView.vue
+++ b/web/admin-spa/src/views/AccountsView.vue
@@ -362,7 +362,7 @@
                             <div class="flex items-start gap-2">
                               <i class="fas fa-gem mt-[2px] text-[10px] text-purple-500"></i>
                               <span class="font-medium text-white dark:text-gray-900"
-                                >Opus 窗口：7天Opus模型专用限额。</span
+                                >Sonnet窗口：7天Sonnet模型专用限额。</span
                               >
                             </div>
                             <div class="flex items-start gap-2">