diff --git a/server/index.js b/server/index.js
index c4ff9c9..8c3a87c 100644
--- a/server/index.js
+++ b/server/index.js
@@ -16,6 +16,7 @@ import checkinRouter from './routes/checkin.js'
 import checklistsRouter from './routes/checklists.js'
 import projectsRouter, { columnRouter } from './routes/projects.js'
 import tasksRouter from './routes/tasks.js'
+import powersyncRouter from './routes/powersync.js'
 
 const PORT = Number(process.env.PORT) || 3001
 const DIST_DIR = path.join(process.cwd(), 'dist')
@@ -33,6 +34,8 @@ app.use('/api/auth', authRouter)
 // OTA 接口是公开的 (检查/下载更新不需要登录), 必须挂载在带 authRequired 的 router 之前,
 // 否则 /api/ota/* 请求会先进入 dataRouter 等并被 authRequired 以 401 拦截
 app.use('/api', otaRouter)
+// PowerSync: token 签发 + 离线上行队列 (自带 authRequired, 同样必须挂在带 authRequired 的业务 router 之前)
+app.use('/api/powersync', powersyncRouter)
 app.use('/api', dataRouter)
 app.use('/api', newsRouter)
 app.use('/api', alertsRouter)
diff --git a/server/routes/powersync.js b/server/routes/powersync.js
new file mode 100644
index 0000000..4a7cdd4
--- /dev/null
+++ b/server/routes/powersync.js
@@ -0,0 +1,375 @@
+// PowerSync 接入: 同步 token 签发 + 客户端上传队列落地 (0.2.1, 见 docs/V0.2/离线编辑模块/0.2.1实施方案.md)
+// 下行由 powersync-service 经 PG 逻辑复制完成; 本文件只负责:
+//   1. /token   为已登录用户签发 powersync-service 接受的 JWT (aud=powersync, 独立密钥可选)
+//   2. /upload  批量落地客户端离线写操作, 按 uuid 幂等 upsert, 服务端统一分配编号
+import { Router } from 'express'
+import jwt from 'jsonwebtoken'
+import { prisma } from '../db.js'
+import { JWT_SECRET, authRequired } from '../middleware.js'
+import { genUuid, normProjectCode, allocProjectCode, withTaskNumber } from '../task-domain/identity.js'
+
+const router = Router()
+
+// ---------- 同步 token ----------
+router.post('/token', authRequired, async (req, res, next) => {
+  try {
+    const user = await prisma.user.findUnique({
+      where: { id: req.user.sub },
+      select: { id: true, name: true, email: true },
+    })
+    if (!user) return res.status(401).json({ error: '用户不存在' })
+    const secret = process.env.POWERSYNC_JWT_SECRET || JWT_SECRET
+    const token = jwt.sign(
+      { sub: String(user.id), aud: 'powersync', name: user.name, email: user.email },
+      secret,
+      { expiresIn: '12h' },
+    )
+    res.json({ token, endpoint: process.env.POWERSYNC_URL || '' })
+  } catch (e) { next(e) }
+})
+
+// ---------- 上传队列 ----------
+// 契约: POST { ops: [{ id, table, op: 'PUT'|'DELETE', uuid, data }] }
+//   table ∈ Project | BoardColumn | ProjectMember | Task | TaskMember | TaskTag
+//   data 为客户端本地全量行; 父引用走 *Uuid 字段 (projectUuid / columnUuid / parentUuid / taskUuid)
+//   返回 { results: [{ id, ok, skipped?, error? }] }, 单条失败不影响同批其它 op
+const TABLES = ['Project', 'BoardColumn', 'ProjectMember', 'Task', 'TaskMember', 'TaskTag']
+const TABLE_RANK = Object.fromEntries(TABLES.map((t, i) => [t, i]))
+
+const COLUMN_RETENTIONS = ['never', 'today', '3d', 'week', 'month', 'forever']
+const TASK_STATUSES = ['todo', 'doing', 'done']
+
+function isoTime(v) {
+  if (!v) return null
+  const d = new Date(v)
+  return Number.isNaN(d.getTime()) ? null : d
+}
+
+// LWW: 服务端已有行不早于客户端数据 => 跳过本次覆盖
+function isStale(existing, data) {
+  const t = isoTime(data?.updatedAt)
+  if (!t) return false
+  return existing.updatedAt && existing.updatedAt.getTime() >= t.getTime()
+}
+
+function cleanExtras(v) {
+  if (!Array.isArray(v)) return []
+  return v.slice(0, 50).map((e) => ({
+    label: String(e?.label ?? '').slice(0, 40),
+    value: String(e?.value ?? ''),
+    url: e?.url ? String(e.url) : '',
+  }))
+}
+
+function cleanNotes(v) {
+  if (!Array.isArray(v)) return []
+  return v.slice(0, 50).map((n) => ({
+    title: String(n?.title ?? '').slice(0, 50),
+    content: String(n?.content ?? '').slice(0, 20000),
+  }))
+}
+
+async function applyPut(op, ctx) {
+  const { userId, assertMember } = ctx
+  const { table, uuid } = op
+  const d = op.data || {}
+  if (!uuid) throw new Error('缺少 uuid')
+
+  if (table === 'Project') {
+    const existing = await prisma.project.findUnique({ where: { uuid } })
+    if (existing) {
+      if (!(await assertMember(existing.id))) throw new Error('无项目权限')
+      if (isStale(existing, d)) return { skipped: true }
+      const data = {}
+      if (d.name !== undefined) {
+        const t = String(d.name).trim()
+        if (!t || t.length > 20) throw new Error('项目名称非法')
+        data.name = t
+      }
+      if (d.archived !== undefined) data.archived = !!d.archived
+      if (d.notes !== undefined) data.notes = cleanNotes(d.notes)
+      if (d.taskKinds !== undefined) {
+        data.taskKinds = Array.isArray(d.taskKinds) ? d.taskKinds.map((k) => String(k).slice(0, 20)).filter(Boolean) : null
+      }
+      if (Object.keys(data).length) await prisma.project.update({ where: { uuid }, data })
+      return {}
+    }
+    const name = String(d.name || '').trim()
+    if (!name || name.length > 20) throw new Error('项目名称非法')
+    const code = normProjectCode(d.code) || (await allocProjectCode(name))
+    const row = await prisma.project.create({
+      data: { uuid, code, name, ownerId: userId, isPersonal: !!d.isPersonal, archived: !!d.archived },
+    })
+    return { rowId: row.id, code: row.code }
+  }
+
+  if (table === 'BoardColumn') {
+    const existing = await prisma.boardColumn.findUnique({ where: { uuid } })
+    if (existing) {
+      if (!(await assertMember(existing.projectId))) throw new Error('无项目权限')
+      if (isStale(existing, d)) return { skipped: true }
+      const data = {}
+      if (d.name !== undefined) {
+        const t = String(d.name).trim()
+        if (!t || t.length > 20) throw new Error('列名非法')
+        data.name = t
+      }
+      if (d.sortOrder !== undefined) data.sortOrder = Number(d.sortOrder) || 0
+      if (d.boundStatus !== undefined) data.boundStatus = TASK_STATUSES.includes(d.boundStatus) ? d.boundStatus : null
+      if (d.retention !== undefined && COLUMN_RETENTIONS.includes(d.retention)) data.retention = d.retention
+      if (Object.keys(data).length) await prisma.boardColumn.update({ where: { uuid }, data })
+      return {}
+    }
+    const project = await prisma.project.findUnique({ where: { uuid: d.projectUuid } })
+    if (!project || !(await assertMember(project.id))) throw new Error('项目不存在或无权限')
+    const name = String(d.name || '').trim()
+    if (!name || name.length > 20) throw new Error('列名非法')
+    await prisma.boardColumn.create({
+      data: {
+        uuid,
+        projectId: project.id,
+        name,
+        sortOrder: Number(d.sortOrder) || 0,
+        boundStatus: TASK_STATUSES.includes(d.boundStatus) ? d.boundStatus : null,
+        retention: COLUMN_RETENTIONS.includes(d.retention) ? d.retention : 'forever',
+      },
+    })
+    return {}
+  }
+
+  if (table === 'ProjectMember') {
+    const existing = await prisma.projectMember.findUnique({ where: { uuid } })
+    if (existing) {
+      // 成员关系只增不改: 已存在即视为完成 (幂等)
+      return { skipped: true }
+    }
+    const project = await prisma.project.findUnique({ where: { uuid: d.projectUuid } })
+    if (!project || !(await assertMember(project.id))) throw new Error('项目不存在或无权限')
+    const target = Number(d.userId)
+    if (!target) throw new Error('userId 非法')
+    const dup = await prisma.projectMember.findUnique({
+      where: { projectId_userId: { projectId: project.id, userId: target } },
+    })
+    if (dup) return { skipped: true }
+    await prisma.projectMember.create({
+      data: { uuid, projectId: project.id, userId: target, permission: d.permission === 'admin' ? 'admin' : 'member' },
+    })
+    return {}
+  }
+
+  if (table === 'Task') {
+    const existing = await prisma.task.findUnique({ where: { uuid } })
+    if (existing) {
+      if (!(await assertMember(existing.projectId))) throw new Error('无项目权限')
+      if (isStale(existing, d)) return { skipped: true }
+      const data = {}
+      if (d.title !== undefined) {
+        const t = String(d.title).trim()
+        if (!t || t.length > 30) throw new Error('任务标题非法')
+        data.title = t
+      }
+      if (d.description !== undefined) data.description = String(d.description || '')
+      if (d.kind !== undefined) data.kind = d.kind ? String(d.kind).trim().slice(0, 20) : null
+      if (d.markDate !== undefined) {
+        const m = isoTime(d.markDate)
+        if (d.markDate && !m) throw new Error('时间标记非法')
+        data.markDate = m
+      }
+      if (d.extras !== undefined) data.extras = cleanExtras(d.extras)
+      if (d.sortOrder !== undefined) data.sortOrder = Number(d.sortOrder) || 0
+      if (d.assigneeId !== undefined) data.assigneeId = d.assigneeId ? Number(d.assigneeId) : null
+      if (d.doneAt !== undefined) data.doneAt = isoTime(d.doneAt)
+      if (d.columnUuid !== undefined) {
+        const col = await prisma.boardColumn.findUnique({ where: { uuid: d.columnUuid } })
+        if (!col || col.projectId !== existing.projectId) throw new Error('看板列不存在')
+        data.columnId = col.id
+      }
+      if (d.parentUuid !== undefined) {
+        if (!d.parentUuid) {
+          data.parentId = null
+        } else {
+          const parent = await prisma.task.findUnique({ where: { uuid: d.parentUuid } })
+          if (!parent || parent.projectId !== existing.projectId) throw new Error('父任务不存在')
+          if (parent.parentId) throw new Error('仅支持一级子任务')
+          data.parentId = parent.id
+        }
+      }
+      if (Object.keys(data).length) await prisma.task.update({ where: { uuid }, data })
+      return {}
+    }
+    // 离线新建: 服务端解析父引用并分配项目内编号
+    const project = await prisma.project.findUnique({ where: { uuid: d.projectUuid } })
+    if (!project || !(await assertMember(project.id))) throw new Error('项目不存在或无权限')
+    const title = String(d.title || '').trim()
+    if (!title || title.length > 30) throw new Error('任务标题非法')
+    let columnId = null
+    if (d.columnUuid) {
+      const col = await prisma.boardColumn.findUnique({ where: { uuid: d.columnUuid } })
+      if (!col || col.projectId !== project.id) throw new Error('看板列不存在')
+      columnId = col.id
+    } else {
+      const first = await prisma.boardColumn.findFirst({
+        where: { projectId: project.id },
+        orderBy: { sortOrder: 'asc' },
+      })
+      if (!first) throw new Error('项目没有可用的看板列')
+      columnId = first.id
+    }
+    let parentId = null
+    if (d.parentUuid) {
+      const parent = await prisma.task.findUnique({ where: { uuid: d.parentUuid } })
+      if (!parent || parent.projectId !== project.id) throw new Error('父任务不存在')
+      if (parent.parentId) throw new Error('仅支持一级子任务')
+      parentId = parent.id
+    }
+    const status = TASK_STATUSES.includes(d.status) ? d.status : 'todo'
+    const base = {
+      uuid,
+      projectId: project.id,
+      columnId,
+      parentId,
+      title,
+      description: String(d.description || ''),
+      kind: d.kind ? String(d.kind).trim().slice(0, 20) : null,
+      markDate: isoTime(d.markDate),
+      status,
+      assigneeId: d.assigneeId ? Number(d.assigneeId) : null,
+      creatorId: userId,
+      extras: cleanExtras(d.extras),
+      doneAt: status === 'done' ? (isoTime(d.doneAt) || new Date()) : null,
+      sortOrder: Number(d.sortOrder) || 0,
+    }
+    const { value: row } = await withTaskNumber(project.id, (number) =>
+      prisma.task.create({ data: { ...base, number } }),
+    )
+    return { rowId: row.id, number: row.number }
+  }
+
+  if (table === 'TaskMember') {
+    const existing = await prisma.taskMember.findUnique({ where: { uuid } })
+    if (existing) return { skipped: true }
+    const task = await prisma.task.findUnique({ where: { uuid: d.taskUuid } })
+    if (!task || !(await assertMember(task.projectId))) throw new Error('任务不存在或无权限')
+    const uid = Number(d.userId)
+    if (!uid) throw new Error('userId 非法')
+    const dup = await prisma.taskMember.findUnique({
+      where: { taskId_userId: { taskId: task.id, userId: uid } },
+    })
+    if (dup) return { skipped: true }
+    await prisma.taskMember.create({ data: { uuid, taskId: task.id, userId: uid } })
+    return {}
+  }
+
+  if (table === 'TaskTag') {
+    const existing = await prisma.taskTag.findUnique({ where: { uuid } })
+    if (existing) return { skipped: true }
+    const task = await prisma.task.findUnique({ where: { uuid: d.taskUuid } })
+    if (!task || !(await assertMember(task.projectId))) throw new Error('任务不存在或无权限')
+    const name = String(d.name || '').trim().slice(0, 20)
+    if (!name) throw new Error('标签名非法')
+    const dup = await prisma.taskTag.findFirst({ where: { taskId: task.id, name } })
+    if (dup) return { skipped: true }
+    await prisma.taskTag.create({ data: { uuid, taskId: task.id, name } })
+    return {}
+  }
+
+  throw new Error('未知表: ' + table)
+}
+
+async function applyDelete(op, ctx) {
+  const { assertMember } = ctx
+  const { table, uuid } = op
+  if (!uuid) throw new Error('缺少 uuid')
+
+  if (table === 'Project') {
+    const row = await prisma.project.findUnique({ where: { uuid }, select: { id: true, isPersonal: true } })
+    if (!row) return { skipped: true }
+    if (!(await assertMember(row.id))) throw new Error('无项目权限')
+    if (row.isPersonal) throw new Error('个人默认项目不可删除')
+    await prisma.project.delete({ where: { uuid } })
+    return {}
+  }
+  if (table === 'BoardColumn') {
+    const row = await prisma.boardColumn.findUnique({ where: { uuid } })
+    if (!row) return { skipped: true }
+    if (!(await assertMember(row.projectId))) throw new Error('无项目权限')
+    await prisma.boardColumn.delete({ where: { uuid } })
+    return {}
+  }
+  if (table === 'ProjectMember') {
+    const row = await prisma.projectMember.findUnique({ where: { uuid } })
+    if (!row) return { skipped: true }
+    if (!(await assertMember(row.projectId))) throw new Error('无项目权限')
+    await prisma.projectMember.delete({ where: { uuid } })
+    return {}
+  }
+  if (table === 'Task') {
+    const row = await prisma.task.findUnique({ where: { uuid } })
+    if (!row) return { skipped: true }
+    if (!(await assertMember(row.projectId))) throw new Error('无项目权限')
+    await prisma.task.delete({ where: { uuid } })
+    return {}
+  }
+  if (table === 'TaskMember') {
+    const row = await prisma.taskMember.findUnique({ where: { uuid } })
+    if (!row) return { skipped: true }
+    const task = await prisma.task.findUnique({ where: { id: row.taskId }, select: { projectId: true } })
+    if (!task || !(await assertMember(task.projectId))) throw new Error('无项目权限')
+    await prisma.taskMember.delete({ where: { uuid } })
+    return {}
+  }
+  if (table === 'TaskTag') {
+    const row = await prisma.taskTag.findUnique({ where: { uuid } })
+    if (!row) return { skipped: true }
+    const task = await prisma.task.findUnique({ where: { id: row.taskId }, select: { projectId: true } })
+    if (!task || !(await assertMember(task.projectId))) throw new Error('无项目权限')
+    await prisma.taskTag.delete({ where: { uuid } })
+    return {}
+  }
+  throw new Error('未知表: ' + table)
+}
+
+router.post('/upload', authRequired, async (req, res, next) => {
+  try {
+    const userId = req.user.sub
+    const ops = Array.isArray(req.body?.ops) ? req.body.ops : []
+    if (!ops.length) return res.status(400).json({ error: 'ops 不能为空' })
+    if (ops.length > 500) return res.status(400).json({ error: '单批 ops 过多 (上限 500)' })
+
+    const memberCache = new Map()
+    const assertMember = async (projectId) => {
+      if (!projectId) return false
+      if (memberCache.has(projectId)) return memberCache.get(projectId)
+      const ok = !!(await prisma.projectMember.findFirst({ where: { projectId, userId } }))
+      memberCache.set(projectId, ok)
+      return ok
+    }
+    const ctx = { userId, assertMember }
+
+    // 依赖顺序: 父表先落地 (Project → BoardColumn → ProjectMember → Task → TaskMember/TaskTag); 删除反向
+    const rank = (o) => TABLE_RANK[o?.table] ?? 99
+    const puts = ops.filter((o) => o && o.op !== 'DELETE').sort((a, b) => rank(a) - rank(b))
+    const dels = ops.filter((o) => o && o.op === 'DELETE').sort((a, b) => rank(b) - rank(a))
+
+    const results = []
+    for (const op of puts) {
+      try {
+        const extra = await applyPut(op, ctx)
+        results.push({ id: op.id, ok: true, ...extra })
+      } catch (e) {
+        results.push({ id: op.id, ok: false, error: e.message })
+      }
+    }
+    for (const op of dels) {
+      try {
+        const extra = await applyDelete(op, ctx)
+        results.push({ id: op.id, ok: true, ...extra })
+      } catch (e) {
+        results.push({ id: op.id, ok: false, error: e.message })
+      }
+    }
+    res.json({ results })
+  } catch (e) { next(e) }
+})
+
+export default router
diff --git a/server/routes/projects.js b/server/routes/projects.js
index 6eecd6f..b21e331 100644
--- a/server/routes/projects.js
+++ b/server/routes/projects.js
@@ -3,6 +3,7 @@ import { Router } from 'express'
 import { prisma } from '../db.js'
 import { authRequired } from '../middleware.js'
 import { loadProjectForUser, loadColumns, loadMemberIds } from '../task-domain/access.js'
+import { genUuid, withUuid, normProjectCode, allocProjectCode } from '../task-domain/identity.js'
 
 const router = Router()
 router.use(authRequired)
@@ -21,7 +22,7 @@ const MAX_NAME = 20
 /** 建 4 个默认列 */
 async function createDefaultColumns(projectId) {
   await prisma.boardColumn.createMany({
-    data: DEFAULT_COLUMNS.map((c) => ({ ...c, projectId, retention: 'forever' })),
+    data: withUuid(DEFAULT_COLUMNS.map((c) => ({ ...c, projectId, retention: 'forever' }))),
   })
 }
 
@@ -32,7 +33,14 @@ export async function ensurePersonalProject(userId) {
   const user = await prisma.user.findUnique({ where: { id: userId }, select: { name: true } })
   const name = `${user?.name || '我'}的任务`
   const project = await prisma.project.create({
-    data: { name, ownerId: userId, isPersonal: true, members: { create: { userId } } },
+    data: {
+      name,
+      ownerId: userId,
+      isPersonal: true,
+      uuid: genUuid(),
+      code: await allocProjectCode(name),
+      members: { create: { uuid: genUuid(), userId } },
+    },
   })
   await createDefaultColumns(project.id)
   return project
@@ -55,6 +63,8 @@ export function normTaskKinds(v) {
 function projectSummary(p) {
   return {
     id: p.id,
+    uuid: p.uuid,
+    code: p.code,
     name: p.name,
     ownerId: p.ownerId,
     isPersonal: p.isPersonal,
@@ -92,8 +102,27 @@ router.post('/', async (req, res, next) => {
     if (!name) return res.status(400).json({ error: '项目名称不能为空' })
     if (name.length > MAX_NAME) return res.status(400).json({ error: `项目名称不能超过 ${MAX_NAME} 字` })
 
+    // 项目短编号: 可由客户端自拟 (2~8 位字母数字, 全局唯一), 未提供时按名称自动分配
+    let code
+    const rawCode = req.body?.code
+    if (rawCode !== undefined && rawCode !== null && String(rawCode).trim() !== '') {
+      code = normProjectCode(rawCode)
+      if (!code) return res.status(400).json({ error: '项目编号须为 2~8 位字母数字' })
+      const dup = await prisma.project.findUnique({ where: { code } })
+      if (dup) return res.status(409).json({ error: `项目编号 ${code} 已被占用` })
+    } else {
+      code = await allocProjectCode(name)
+    }
+
     const project = await prisma.project.create({
-      data: { name, ownerId: userId, isPersonal: false, members: { create: { userId } } },
+      data: {
+        name,
+        ownerId: userId,
+        isPersonal: false,
+        uuid: genUuid(),
+        code,
+        members: { create: { uuid: genUuid(), userId } },
+      },
     })
     await createDefaultColumns(project.id)
     const full = await prisma.project.findUnique({
@@ -135,7 +164,7 @@ router.put('/:id', async (req, res, next) => {
     const userId = req.user.sub
     const project = await loadProjectForUser(req.params.id, userId)
     if (!project) return res.status(404).json({ error: '项目不存在或无权限' })
-    const { name, archived, notes, taskKinds, icon } = req.body || {}
+    const { name, archived, notes, taskKinds, icon, code } = req.body || {}
     const data = {}
     if (name !== undefined) {
       const t = String(name).trim()
@@ -143,6 +172,16 @@ router.put('/:id', async (req, res, next) => {
       if (t.length > MAX_NAME) return res.status(400).json({ error: `项目名称不能超过 ${MAX_NAME} 字` })
       data.name = t
     }
+    // 项目短编号: 可修改 (2~8 位字母数字, 全局唯一)
+    if (code !== undefined) {
+      const c = normProjectCode(code)
+      if (!c) return res.status(400).json({ error: '项目编号须为 2~8 位字母数字' })
+      if (c !== project.code) {
+        const dup = await prisma.project.findUnique({ where: { code: c } })
+        if (dup) return res.status(409).json({ error: `项目编号 ${c} 已被占用` })
+        data.code = c
+      }
+    }
     // 任务类型标签: 整体替换; 空数组回落默认
     if (taskKinds !== undefined) {
       if (!Array.isArray(taskKinds)) return res.status(400).json({ error: '任务类型格式非法' })
@@ -206,7 +245,7 @@ router.post('/:id/members', async (req, res, next) => {
     })
     if (exist) return res.status(409).json({ error: '该用户已是项目成员' })
 
-    await prisma.projectMember.create({ data: { projectId: project.id, userId: target.id } })
+    await prisma.projectMember.create({ data: { uuid: genUuid(), projectId: project.id, userId: target.id } })
     res.json({ ok: true, member: { userId: target.id, name: target.name } })
   } catch (e) { next(e) }
 })
diff --git a/server/routes/tasks.js b/server/routes/tasks.js
index b62f235..1ad8123 100644
--- a/server/routes/tasks.js
+++ b/server/routes/tasks.js
@@ -8,6 +8,7 @@ import {
 import { resolveTaskWrite } from '../task-domain/resolveStatus.js'
 import { filterVisible } from '../task-domain/retention.js'
 import { copyTask } from '../task-domain/copyTask.js'
+import { genUuid, withUuid, withTaskNumber } from '../task-domain/identity.js'
 
 const router = Router()
 router.use(authRequired)
@@ -101,28 +102,30 @@ router.post('/projects/:id/tasks', async (req, res, next) => {
     }
 
     const firstCol = columns[0]
-    const row = await prisma.task.create({
-      data: {
-        projectId: project.id,
-        columnId: firstCol.id,
-        parentId: pid,
-        title: cleanTitle,
-        description: String(description || ''),
-        kind: kind ? String(kind).trim().slice(0, 20) : null,
-        markDate: mark,
-        status: firstCol.boundStatus || 'todo',
-        assigneeId: finalAssignee,
-        creatorId: userId,
-        extras: [],
-        members: {
-          create: (Array.isArray(memberIds) ? memberIds : [])
-            .map(Number).filter((id) => memberSet.has(id))
-            .map((uid) => ({ userId: uid })),
-        },
-        tags: { create: (Array.isArray(tags) ? tags : []).filter(Boolean).map((n) => ({ name: String(n).slice(0, 20) })) },
+    const taskData = {
+      uuid: req.body?.uuid || genUuid(),
+      projectId: project.id,
+      columnId: firstCol.id,
+      parentId: pid,
+      title: cleanTitle,
+      description: String(description || ''),
+      kind: kind ? String(kind).trim().slice(0, 20) : null,
+      markDate: mark,
+      status: firstCol.boundStatus || 'todo',
+      assigneeId: finalAssignee,
+      creatorId: userId,
+      extras: [],
+      members: {
+        create: withUuid((Array.isArray(memberIds) ? memberIds : [])
+          .map(Number).filter((id) => memberSet.has(id))
+          .map((uid) => ({ userId: uid }))),
       },
-      include: TASK_INCLUDE,
-    })
+      tags: { create: withUuid((Array.isArray(tags) ? tags : []).filter(Boolean).map((n) => ({ name: String(n).slice(0, 20) }))) },
+    }
+    // 项目内自增编号 (展示 `code-number`): 服务端分配, 并发冲突时重取 max+1 重试
+    const { value: row } = await withTaskNumber(project.id, (number) =>
+      prisma.task.create({ data: { ...taskData, number }, include: TASK_INCLUDE }),
+    )
     res.json({ item: shape(row) })
   } catch (e) { next(e) }
 })
@@ -250,7 +253,7 @@ router.put('/tasks/:id', async (req, res, next) => {
       await prisma.taskMember.deleteMany({ where: { taskId: task.id } })
       if (ids.length) {
         await prisma.taskMember.createMany({
-          data: ids.map((uid) => ({ taskId: task.id, userId: uid })),
+          data: withUuid(ids.map((uid) => ({ taskId: task.id, userId: uid }))),
         })
       }
     }
@@ -258,7 +261,7 @@ router.put('/tasks/:id', async (req, res, next) => {
       await prisma.taskTag.deleteMany({ where: { taskId: task.id } })
       const names = body.tags.map((n) => String(n).trim()).filter(Boolean).slice(0, 10)
       if (names.length) {
-        await prisma.taskTag.createMany({ data: names.map((name) => ({ taskId: task.id, name: name.slice(0, 20) })) })
+        await prisma.taskTag.createMany({ data: withUuid(names.map((name) => ({ taskId: task.id, name: name.slice(0, 20) }))) })
       }
     }
 
diff --git a/server/task-domain/copyTask.js b/server/task-domain/copyTask.js
index 1af23f5..fc8cf0b 100644
--- a/server/task-domain/copyTask.js
+++ b/server/task-domain/copyTask.js
@@ -1,6 +1,7 @@
 // 任务模块: 跨项目拷贝 (T-CP-*)
 // 拷贝而非移动: 新建记录 + 深拷贝子任务, 源任务零改动.
 import { prisma } from '../db.js'
+import { genUuid, withUuid, withTaskNumber } from './identity.js'
 
 /**
  * 拷贝一条任务(含子任务)到目标项目。
@@ -38,6 +39,7 @@ export async function copyTask({ source, targetProject, targetColumns, operatorI
   const droppedAssignee = source.assigneeId && !memberSet.has(source.assigneeId) ? source.assignee : null
 
   const baseData = (extra) => ({
+    uuid: genUuid(),
     projectId: targetProject.id,
     title: source.title,
     description: source.description || '',
@@ -50,33 +52,39 @@ export async function copyTask({ source, targetProject, targetColumns, operatorI
     doneAt: source.status === 'done' ? (source.doneAt || new Date()) : null,
     sortOrder: source.sortOrder ?? 0,
     tags: {
-      create: (source.tags || []).map((t) => ({ name: t.name })),
+      create: withUuid((source.tags || []).map((t) => ({ name: t.name }))),
     },
   })
 
-  const newTask = await prisma.task.create({
-    data: {
-      ...baseData({ columnId: pickColumn(source.columnId) }),
-      members: {
-        create: keptMemberIds.map((uid) => ({ userId: uid })),
+  const { value: newTask } = await withTaskNumber(targetProject.id, (number) =>
+    prisma.task.create({
+      data: {
+        ...baseData({ columnId: pickColumn(source.columnId) }),
+        number,
+        members: {
+          create: withUuid(keptMemberIds.map((uid) => ({ userId: uid }))),
+        },
       },
-    },
-  })
+    }),
+  )
 
   // 子任务: 同法复制, parentId 指向新父任务
   for (const child of source.children || []) {
     const childMembers = (child.members || [])
       .filter((m) => memberSet.has(m.userId))
       .map((m) => m.userId)
-    await prisma.task.create({
-      data: {
-        ...baseData({
-          columnId: pickColumn(child.columnId),
-          parentId: newTask.id,
-        }),
-        members: { create: childMembers.map((uid) => ({ userId: uid })) },
-      },
-    })
+    await withTaskNumber(targetProject.id, (number) =>
+      prisma.task.create({
+        data: {
+          ...baseData({
+            columnId: pickColumn(child.columnId),
+            parentId: newTask.id,
+          }),
+          number,
+          members: { create: withUuid(childMembers.map((uid) => ({ userId: uid }))) },
+        },
+      }),
+    )
   }
 
   return {
diff --git a/server/task-domain/identity.js b/server/task-domain/identity.js
new file mode 100644
index 0000000..a0fdc66
--- /dev/null
+++ b/server/task-domain/identity.js
@@ -0,0 +1,74 @@
+// 任务域同步标识与编号 (0.2.1 离线编辑, 见 docs/V0.2/离线编辑模块/0.2.1实施方案.md)
+// 约定: 任务域 6 表均带 uuid(客户端/服务端创建时生成, 上行按 uuid 幂等);
+//       Project.code 为用户自拟 2~8 位字母数字短编号(存储大写, 全局唯一);
+//       Task.number 为项目内自增编号, 服务端分配, 展示 `code-number`。
+import crypto from 'node:crypto'
+import { prisma } from '../db.js'
+
+/** 同步标识: 服务端创建行时统一生成 uuid */
+export function genUuid() {
+  return crypto.randomUUID()
+}
+
+/** 为多行数据补 uuid (createMany 前用) */
+export function withUuid(rows) {
+  return rows.map((r) => ({ ...r, uuid: r.uuid || genUuid() }))
+}
+
+// 项目编号: 2~8 位字母数字, 存储统一大写 (任务展示 `编号-序号`, 不允许连字符)
+const CODE_RE = /^[A-Z0-9]{2,8}$/
+
+/** 归一化项目编号; 非法返回 null */
+export function normProjectCode(v) {
+  const s = String(v || '').trim().toUpperCase()
+  return CODE_RE.test(s) ? s : null
+}
+
+function randCode(len) {
+  return crypto.randomBytes(len * 2).toString('hex').toUpperCase().replace(/[^A-Z0-9]/g, '').padEnd(len, 'X').slice(0, len)
+}
+
+/** 从项目名推导候选编号: 取 ASCII 字母数字, 不足则随机补齐 */
+function suggestCode(name) {
+  const letters = String(name || '').toUpperCase().replace(/[^A-Z0-9]/g, '')
+  if (letters.length >= 2) return letters.slice(0, 8)
+  return (letters + randCode(8)).slice(0, 8)
+}
+
+/** 分配一个未占用的项目编号: 优先按名称推导, 冲突则随机尾缀重试 */
+export async function allocProjectCode(name) {
+  const base = suggestCode(name)
+  for (let i = 0; i < 20; i++) {
+    const cand = i === 0 ? base : (base.slice(0, 5) + randCode(3)).slice(0, 8)
+    if (cand.length < 2 || !CODE_RE.test(cand)) continue
+    const dup = await prisma.project.findUnique({ where: { code: cand } })
+    if (!dup) return cand
+  }
+  while (true) {
+    const cand = randCode(6)
+    const dup = await prisma.project.findUnique({ where: { code: cand } })
+    if (!dup) return cand
+  }
+}
+
+/** 任务项目内下一个编号 (max+1); 并发冲突由调用方捕获 P2002 重试 */
+export async function nextTaskNumber(projectId) {
+  const agg = await prisma.task.aggregate({ where: { projectId }, _max: { number: true } })
+  return (agg._max.number ?? 0) + 1
+}
+
+/** Task.number 唯一冲突重试包装: fn(number) 返回 Promise; 冲突时重取编号, 最多 3 次 */
+export async function withTaskNumber(projectId, fn) {
+  let lastErr = null
+  for (let attempt = 0; attempt < 3; attempt++) {
+    const number = await nextTaskNumber(projectId)
+    try {
+      return { number, value: await fn(number) }
+    } catch (e) {
+      const target = Array.isArray(e?.meta?.target) ? e.meta.target.join(',') : String(e?.meta?.target || '')
+      lastErr = e
+      if (!(e?.code === 'P2002' && target.includes('number'))) throw e
+    }
+  }
+  throw lastErr
+}