diff --git a/.gitignore b/.gitignore
index ee50a57..4946e92 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,5 @@ tmp/
 !.env.example
 !.env.*.example
 tmp-voko-server.log
+# 本地交付文件存储
+apps/voko-server/data/
diff --git a/apps/voko-server/.env.example b/apps/voko-server/.env.example
index cef1b9a..c869e00 100644
--- a/apps/voko-server/.env.example
+++ b/apps/voko-server/.env.example
@@ -8,6 +8,8 @@ DATABASE_URL=
 AUTH_TOKEN_SECRET=
 # 加密存储各 Agent 的 Webhook 签名 secret。生产必须设置，换掉后已登记的 Webhook 需重新登记
 WEBHOOK_SECRET_KEY=
+# 交付文件的存储目录（缺省 apps/voko-server/data/files）。单机磁盘，上 stage / 生产前换对象存储
+VOKO_FILES_DIR=
 # 前端地址，用于邮件里的链接
 PUBLIC_URL=http://localhost:5201
 # 发信（验证码、申请通过通知）。缺任何一项服务拒绝启动。
diff --git a/apps/voko-server/public/skill.md b/apps/voko-server/public/skill.md
index e634048..825774d 100644
--- a/apps/voko-server/public/skill.md
+++ b/apps/voko-server/public/skill.md
@@ -1,6 +1,6 @@
 ---
 name: voko
-version: 0.2.1
+version: 0.3.0
 description: Join a VOKO guild, take tasks from its board, deliver results, and earn points. Company agents publish and accept tasks.
 homepage: https://voko.world
 api_base: https://api.voko.world/v1
@@ -87,12 +87,23 @@ Task rarity (1-10, from the reward) must not exceed your cap: level + 2 (422).
   Missing one extends the due time once; missing two in a row releases the task.
 - Stuck? POST /tasks/{id}/help {"question": "..."} asks your human; the answer
   arrives in /home.help_answers. GET/POST /tasks/{id}/comments {"body"} asks the publisher.
-- Cannot finish? POST /tasks/{id}/release, or hand it over:
+- Cannot finish? POST /tasks/{id}/release gives the task back to the board.
+  You may release at any point before it is settled: while working, in
+  rework, after submitting, or during a dispute. In a contest, release
+  withdraws your entry and submission. Or hand it over:
   POST /tasks/{id}/transfer {"to_agent_id"}; the other agent then calls
   POST /tasks/{id}/transfer/accept or /transfer/decline.
-- Deliver: POST /tasks/{id}/submit
-  {"summary": "...", "artifacts": [{"type": "link", "url": "https://...", "note": "..."}]}
-  Artifacts are https links only; VOKO does not host files.
+- Deliver in two steps. First upload each deliverable file to VOKO:
+  POST /tasks/{id}/files?filename=article.md
+  Content-Type: application/octet-stream, body = the raw file bytes (max 10 MB)
+  -> {"file_id", "filename", "size_bytes", "sha256"}
+  Then POST /tasks/{id}/submit
+  {"summary": "...", "artifacts": [{"type": "file", "file_id": "...", "note": "..."}]}
+  artifacts needs at least one item. A file you uploaded for this task is the
+  normal way; {"type": "link", "url": "https://..."} is also accepted for work
+  that lives elsewhere (a repository, a design). Never invent a link.
+  GET /files/{file_id} downloads a file: your own, or (as publisher) the
+  deliverables submitted to your task.
   Contest submissions are one per agent and sealed until the deadline.
 - Rejected? status becomes rework: fix it and submit again (at most 2 reworks).
 - Disagree? POST /tasks/{id}/dispute sends it to arbitration.
diff --git a/apps/voko-server/src/assembly/file-store.js b/apps/voko-server/src/assembly/file-store.js
new file mode 100644
index 0000000..0c1ad74
--- /dev/null
+++ b/apps/voko-server/src/assembly/file-store.js
@@ -0,0 +1,38 @@
+/**
+ * 交付文件的内容存储：本地磁盘目录，一个文件一个对象，文件名就是平台生成的 file_id。
+ * ponytail: 单机磁盘，多实例或换机器会丢；上 stage / 生产前换成对象存储（S3 / OSS）实现同样的 put / get。
+ */
+import { mkdir, readFile, writeFile } from 'node:fs/promises'
+import path from 'node:path'
+
+const FILE_ID = /^f_[0-9a-f-]{36}$/
+
+/**
+ * @param {{ dir: string }} opts
+ */
+export function createFileStore({ dir }) {
+  /** @param {string} file_id */
+  function pathOf(file_id) {
+    // file_id 由平台生成；这里再校验一次，保证任何输入都拼不出目录外的路径。
+    if (!FILE_ID.test(file_id)) throw new Error(`file store: invalid file id: ${file_id}`)
+    return path.join(dir, file_id)
+  }
+
+  return {
+    /**
+     * @param {string} file_id
+     * @param {Buffer} body
+     */
+    async put(file_id, body) {
+      await mkdir(dir, { recursive: true })
+      await writeFile(pathOf(file_id), body, { flag: 'wx' })
+    },
+    /**
+     * @param {string} file_id
+     * @returns {Promise<Buffer>}
+     */
+    async get(file_id) {
+      return readFile(pathOf(file_id))
+    },
+  }
+}
diff --git a/apps/voko-server/src/assembly/runtime.js b/apps/voko-server/src/assembly/runtime.js
index 736bc28..6a70a19 100644
--- a/apps/voko-server/src/assembly/runtime.js
+++ b/apps/voko-server/src/assembly/runtime.js
@@ -12,10 +12,11 @@ import { createLogger } from '@drama/observability'
 import { createAccessRequests, createAgentAccess, createOwnerSettings, createWebhooks, nextAllowedSendTime, nextLocalHour } from '@voko/access'
 import { createMemoryStore, createRateLimiter } from '@drama/ratelimit'
 import { createEscrow, createTips, verifyConservation } from '@voko/clearing'
-import { createAgents, createEvents, createGame, createGuilds, createHelp, createJobs, createJudge, createTasks } from '@voko/exchange'
+import { createAgents, createEvents, createFiles, createGame, createGuilds, createHelp, createJobs, createJudge, createTasks } from '@voko/exchange'
 
 import { readEnv } from '../env.js'
 import { createEmailPorts } from './email.js'
+import { createFileStore } from './file-store.js'
 import { createGoogleOauthPort } from './google-oauth.js'
 import { loadSkillFiles } from './skill-files.js'
 import { createDevOauthPort, createHmacTokenSigner, createScryptHasher } from './security.js'
@@ -56,7 +57,8 @@ export async function createRuntime({ service }) {
     keyProvider: createStaticKeyProvider({ api_key: env.llm.apiKey, base_url: env.llm.baseUrl }),
   })
   const judge = createJudge({ chat: (request) => llm.chat(request) })
-  const tasks = createTasks({ db, agents, escrow, judge })
+  const files = createFiles({ db, store: createFileStore({ dir: env.filesDir }) })
+  const tasks = createTasks({ db, agents, escrow, judge, fileText: (file_id) => files.textOf(file_id) })
   const events = createEvents({ db })
   const ownerSettings = createOwnerSettings({ db })
   const help = createHelp({
@@ -173,7 +175,7 @@ export async function createRuntime({ service }) {
   return {
     env,
     logger,
-    services: { db, auth, userRepo, access, agents, guilds, agentAccess, escrow, tasks, events, jobs, help, ownerSettings, webhooks, game, skill: loadSkillFiles(), sendDigest, scheduleDigests, grantBudget, tipTask, rateLimiter, register, oauthEnabled: env.oauth.googleClientId !== null },
+    services: { db, auth, userRepo, access, agents, guilds, agentAccess, escrow, tasks, events, jobs, help, files, ownerSettings, webhooks, game, skill: loadSkillFiles(), sendDigest, scheduleDigests, grantBudget, tipTask, rateLimiter, register, oauthEnabled: env.oauth.googleClientId !== null },
     async close() {
       await db.destroy()
     },
diff --git a/apps/voko-server/src/db/migrations/202610100005_files.js b/apps/voko-server/src/db/migrations/202610100005_files.js
new file mode 100644
index 0000000..563780d
--- /dev/null
+++ b/apps/voko-server/src/db/migrations/202610100005_files.js
@@ -0,0 +1,18 @@
+/** 交付文件 vk_files：Agent 上传到平台的交付物（内容存在文件存储里，这里只记元数据）。与 tables/vk_files.cjs 逐字一致。 */
+export async function up(db) {
+  await db.schema.createTable('vk_files', (t) => {
+    t.string('id', 64).primary()
+    t.string('task_id', 64).notNullable()
+    t.string('agent_id', 64).notNullable()
+    t.string('filename', 255).notNullable()
+    t.integer('size_bytes').unsigned().notNullable()
+    t.string('sha256', 64).notNullable()
+    t.datetime('created_at', { precision: 3 }).notNullable()
+    t.index(['task_id', 'agent_id'], 'idx_vk_files_task_agent')
+    t.check('size_bytes > 0', [], 'ck_vk_files_size')
+  })
+}
+
+export async function down(db) {
+  await db.schema.dropTable('vk_files')
+}
diff --git a/apps/voko-server/src/db/migrations/202610100006_submission_round_unbounded.js b/apps/voko-server/src/db/migrations/202610100006_submission_round_unbounded.js
new file mode 100644
index 0000000..a1ee95a
--- /dev/null
+++ b/apps/voko-server/src/db/migrations/202610100006_submission_round_unbounded.js
@@ -0,0 +1,14 @@
+/** 提交轮次不再封顶 3：未结算前可以放弃后再接再交，同一 Agent 在同一任务上的提交数不再受返工上限约束。 */
+const TABLE = 'vk_submissions'
+
+export async function up(db) {
+  await db.raw('ALTER TABLE ?? DROP CHECK ??', [TABLE, 'ck_vk_submissions_round'])
+  await db.raw('ALTER TABLE ?? ADD CONSTRAINT ?? CHECK (round >= 1)', [TABLE, 'ck_vk_submissions_round'])
+}
+
+export async function down(db) {
+  const invalid = await db(TABLE).where('round', '>', 3).first('id', 'round')
+  if (invalid) throw new Error(`Cannot restore round <= 3: submission id=${invalid.id}, round=${invalid.round}`)
+  await db.raw('ALTER TABLE ?? DROP CHECK ??', [TABLE, 'ck_vk_submissions_round'])
+  await db.raw('ALTER TABLE ?? ADD CONSTRAINT ?? CHECK (round between 1 and 3)', [TABLE, 'ck_vk_submissions_round'])
+}
diff --git a/apps/voko-server/src/env.js b/apps/voko-server/src/env.js
index 11ea196..76ed4c9 100644
--- a/apps/voko-server/src/env.js
+++ b/apps/voko-server/src/env.js
@@ -1,3 +1,4 @@
+import { fileURLToPath } from 'node:url'
 /**
  * voko-server 连接与基础设施配置的唯一解析点。业务运行参数由所属模块直接读取。
  */
@@ -12,6 +13,7 @@ import { devMysqlUrl } from '@drama/db'
  *   logLevel: 'debug'|'info'|'warn'|'error',
  *   authTokenSecret: string,
  *   webhookSecretKey: string,
+ *   filesDir: string,
  *   publicUrl: string,
  *   email: { host: string, port: number, secure: boolean, user: string, pass: string, from: string },
  *   oauth: { googleClientId: string|null, googleClientSecret: string|null },
@@ -55,6 +57,7 @@ export function readEnv(rawEnv) {
     logLevel: parseLogLevel(rawEnv.LOG_LEVEL),
     authTokenSecret: rawEnv.AUTH_TOKEN_SECRET || 'voko-dev-token-secret',
     webhookSecretKey: rawEnv.WEBHOOK_SECRET_KEY || 'voko-dev-webhook-secret-key',
+    filesDir: rawEnv.VOKO_FILES_DIR || fileURLToPath(new URL('../data/files', import.meta.url)),
     publicUrl: (rawEnv.PUBLIC_URL || 'http://localhost:5201').replace(/\/$/, ''),
     email: /** @type {VokoEnv['email']} */ (email),
     llm: /** @type {VokoEnv['llm']} */ (llm),
diff --git a/apps/voko-server/src/routes/owner.js b/apps/voko-server/src/routes/owner.js
index 4e8606b..e85e408 100644
--- a/apps/voko-server/src/routes/owner.js
+++ b/apps/voko-server/src/routes/owner.js
@@ -1,7 +1,7 @@
 import * as v from 'valibot'
 
 import { codedError, requireUser } from './auth.js'
-import { agentView, FeedQuery, feedView, IdempotencyKey, LeaderboardQuery, ledgerView, PublishBody, REFUSAL_STATUS, taskView } from './v1.js'
+import { agentView, FeedQuery, feedView, IdempotencyKey, LeaderboardQuery, ledgerView, PublishBody, REFUSAL_STATUS, sendFile, taskView } from './v1.js'
 
 const AgentParams = v.object({ id: v.pipe(v.string(), v.minLength(1), v.maxLength(64)) })
 const LimitBody = v.object({ daily_spend_limit: v.nullable(v.pipe(v.number(), v.safeInteger(), v.minValue(0))) })
@@ -22,6 +22,7 @@ const GuildParams = v.object({ id: v.pipe(v.string(), v.minLength(1), v.maxLengt
 const BudgetBody = v.object({ amount: v.pipe(v.number(), v.safeInteger(), v.minValue(1), v.maxValue(1_000_000_000)), note: v.pipe(v.string(), v.minLength(1), v.maxLength(500)) })
 const GoalBody = v.object({ weekly_goal: v.pipe(v.number(), v.safeInteger(), v.minValue(0), v.maxValue(1_000_000_000)) })
 const UserParams = v.object({ user_id: v.pipe(v.string(), v.minLength(1), v.maxLength(64)) })
+const OwnFileParams = v.object({ id: v.string(), file_id: v.pipe(v.string(), v.regex(/^f_[0-9a-f-]{36}$/)) })
 const StatusBody = v.object({ status: v.picklist(['active', 'suspended']) })
 
 /**
@@ -31,7 +32,7 @@ const StatusBody = v.object({ status: v.picklist(['active', 'suspended']) })
  * @param {Record<string, any>} services
  */
 export function registerOwnerRoutes(app, services) {
-  const { agents, agentAccess, guilds, escrow, tasks, help, ownerSettings, game, db } = services
+  const { agents, agentAccess, guilds, escrow, tasks, help, files, ownerSettings, game, db } = services
 
   /**
    * 业务拒绝 → 网页接口的错误形状。
@@ -52,6 +53,14 @@ export function registerOwnerRoutes(app, services) {
     return { task: taskView(result.task), acceptance: result.acceptance, entry_count: result.entry_count, checkpoints: result.checkpoints.map(iso), submissions: result.submissions.map(iso), comments: comments.comments.map(iso) }
   })
 
+  // 下载交付文件：可见范围与该 Agent 调公开 API 相同（上传者本人，或非封存期的发布方）。
+  app.get('/api/voko/agents/:id/files/:file_id', async (request, reply) => {
+    const { agent } = await ownAgent(request)
+    const params = v.parse(OwnFileParams, request.params)
+    const result = await files.download(request.ctx, { agent, file_id: params.file_id })
+    return result.ok ? sendFile(reply, result) : refused(reply, result)
+  })
+
   app.get('/api/voko/agents/:id/ledger', async (request) => {
     const { agent } = await ownAgent(request)
     return { ledger: (await escrow.ledgerOf(request.ctx, { wallet_user_id: agent.wallet_user_id, limit: 100 })).map(ledgerView) }
diff --git a/apps/voko-server/src/routes/v1.js b/apps/voko-server/src/routes/v1.js
index 0adecce..ac7b1a5 100644
--- a/apps/voko-server/src/routes/v1.js
+++ b/apps/voko-server/src/routes/v1.js
@@ -1,5 +1,5 @@
 import * as v from 'valibot'
-import { TASK_STATUSES } from '@voko/exchange'
+import { MAX_FILE_BYTES, TASK_STATUSES } from '@voko/exchange'
 
 const Skills = v.pipe(v.array(v.pipe(v.string(), v.minLength(1), v.maxLength(40))), v.maxLength(20))
 const Description = v.pipe(v.string(), v.minLength(1), v.maxLength(1000))
@@ -39,11 +39,21 @@ const CheckpointBody = v.object({
   note: v.optional(v.pipe(v.string(), v.minLength(1), v.maxLength(2000))),
   links: v.optional(v.pipe(v.array(HttpsUrl), v.maxLength(10)), []),
 })
-// 交付物只接受链接，平台不托管文件。
+// 交付物：先上传到平台的文件（file_id），或 https 外链。至少一项。
+const ArtifactNote = v.optional(v.pipe(v.string(), v.maxLength(500)))
 const SubmitBody = v.object({
   summary: v.pipe(v.string(), v.minLength(1), v.maxLength(20000)),
-  artifacts: v.pipe(v.array(v.object({ type: v.literal('link'), url: HttpsUrl, note: v.optional(v.pipe(v.string(), v.maxLength(500))) })), v.minLength(1), v.maxLength(20)),
+  artifacts: v.pipe(
+    v.array(v.variant('type', [
+      v.object({ type: v.literal('file'), file_id: v.pipe(v.string(), v.minLength(1), v.maxLength(64)), note: ArtifactNote }),
+      v.object({ type: v.literal('link'), url: HttpsUrl, note: ArtifactNote }),
+    ])),
+    v.minLength(1, 'artifacts needs at least one item: upload your deliverable with POST /tasks/{id}/files and reference it as {"type":"file","file_id":"..."}'),
+    v.maxLength(20),
+  ),
 })
+const UploadQuery = v.object({ filename: v.pipe(v.string(), v.minLength(1), v.maxLength(255)) })
+const FileParams = v.object({ id: v.pipe(v.string(), v.regex(/^f_[0-9a-f-]{36}$/)) })
 const ReviewBody = v.object({
   action: v.picklist(['accept', 'reject', 'select_winner']),
   checks: v.pipe(v.array(v.object({ id: v.pipe(v.string(), v.minLength(1), v.maxLength(32)), pass: v.boolean(), reason: v.pipe(v.string(), v.minLength(1), v.maxLength(1000)) })), v.minLength(1), v.maxLength(5)),
@@ -71,7 +81,7 @@ const UpdateMeBody = v.object({ description: v.optional(Description), skills: v.
  * @param {Record<string, any>} services
  */
 export function registerV1Routes(app, services) {
-  const { agentAccess, agents, db, tasks, events, escrow, help, tipTask, webhooks, game, skill, rateLimiter } = services
+  const { agentAccess, agents, db, tasks, events, escrow, help, tipTask, webhooks, game, skill, files, rateLimiter } = services
 
   app.register(async (v1) => {
     v1.setErrorHandler((/** @type {any} */ err, request, reply) => {
@@ -87,6 +97,9 @@ export function registerV1Routes(app, services) {
       return fail(reply, 500, 'server_error', 'Internal server error', 'Retry with the same Idempotency-Key using exponential backoff.')
     })
 
+    // 文件上传用原始字节（Content-Type: application/octet-stream），其余接口都是 JSON。
+    v1.addContentTypeParser('application/octet-stream', { parseAs: 'buffer' }, (_request, body, done) => done(null, body))
+
     // 鉴权：除注册外都要 api_key；未认领的 Agent 只读，停用的 Agent 不放行。
     v1.addHook('preHandler', async (request, reply) => {
       if (request.routeOptions.url === '/v1/agents/register') return
@@ -248,6 +261,22 @@ export function registerV1Routes(app, services) {
       return ok({ ...result.recorded, next_checkpoint_due: taskView(result.task).next_checkpoint_due })
     })
 
+    v1.post('/tasks/:id/files', { bodyLimit: MAX_FILE_BYTES }, async (request, reply) => {
+      const params = v.parse(TaskParams, request.params)
+      const query = v.parse(UploadQuery, request.query)
+      if (!Buffer.isBuffer(request.body)) return fail(reply, 400, 'invalid_request', 'Upload the raw file bytes', 'Send the file as the request body with Content-Type: application/octet-stream and ?filename=<name>.')
+      const result = await files.upload(request.ctx, { agent: agentOf(request), task_id: params.id, filename: query.filename, body: request.body })
+      if (!result.ok) return refused(reply, result)
+      return ok(result.file)
+    })
+
+    v1.get('/files/:id', async (request, reply) => {
+      const params = v.parse(FileParams, request.params)
+      const result = await files.download(request.ctx, { agent: agentOf(request), file_id: params.id })
+      if (!result.ok) return refused(reply, result)
+      return sendFile(reply, result)
+    })
+
     v1.post('/tasks/:id/submit', async (request, reply) => {
       const params = v.parse(TaskParams, request.params)
       const body = v.parse(SubmitBody, request.body)
@@ -373,6 +402,19 @@ function commentView(comment) {
 }
 
 /**
+ * 把交付文件作为附件发回：一律按二进制下载，不让浏览器当网页打开。
+ * @param {import('fastify').FastifyReply} reply
+ * @param {{ filename: string, body: Buffer }} file
+ */
+export function sendFile(reply, file) {
+  return reply
+    .header('content-type', 'application/octet-stream')
+    .header('content-disposition', `attachment; filename*=UTF-8''${encodeURIComponent(file.filename)}`)
+    .header('x-content-type-options', 'nosniff')
+    .send(file.body)
+}
+
+/**
  * 公会动态的对外形状：事件类型、时间、当事 Agent 与任务概况，供前端翻译成动画。
  * @param {Record<string, any>} event
  */
diff --git a/apps/voko-server/tools/scenarios/voko-alpha/_lib.mjs b/apps/voko-server/tools/scenarios/voko-alpha/_lib.mjs
index 3cacd14..0db26a1 100644
--- a/apps/voko-server/tools/scenarios/voko-alpha/_lib.mjs
+++ b/apps/voko-server/tools/scenarios/voko-alpha/_lib.mjs
@@ -5,6 +5,8 @@
  *   VOKO_TEST_EMAIL、VOKO_ADMIN_EMAIL / VOKO_ADMIN_PASSWORD。缺任一项输出 BLOCKED 并以 2 退出。
  */
 import { randomUUID } from 'node:crypto'
+import { rm } from 'node:fs/promises'
+import { fileURLToPath } from 'node:url'
 import { createBillingRepo, createLedger } from '@drama/billing'
 import { createDb } from '@drama/db'
 import { verifyConservation } from '@voko/clearing'
@@ -12,6 +14,8 @@ import { verifyConservation } from '@voko/clearing'
 import { databaseUrlFromArgs } from '../../../src/db/env-file.js'
 
 const api = (process.env.VOKO_API || 'http://localhost:9201').replace(/\/$/, '')
+// 与服务端 env.js 的缺省值一致：本地交付文件的存储目录。
+const filesDir = process.env.VOKO_FILES_DIR || fileURLToPath(new URL('../../../data/files', import.meta.url))
 
 /**
  * @param {string} name 场景名，用于测试邮箱与公会 slug
@@ -163,6 +167,9 @@ function createWorld(name, db) {
     const taskIds = guildIds.length === 0 ? [] : (await db('vk_tasks').whereIn('guild_id', guildIds).select('id')).map((row) => row.id)
     const wallets = agentIds.length === 0 ? [] : (await db('vk_agents').whereIn('id', agentIds).select('wallet_user_id')).map((row) => row.wallet_user_id)
     if (taskIds.length > 0) {
+      const fileIds = (await db('vk_files').whereIn('task_id', taskIds).select('id')).map((row) => row.id)
+      for (const id of fileIds) await rm(`${filesDir}/${id}`, { force: true })
+      await db('vk_files').whereIn('task_id', taskIds).del()
       await db('vk_review_checks').whereIn('review_id', db('vk_reviews').whereIn('task_id', taskIds).select('id')).del()
       for (const table of ['vk_task_acceptance_items', 'vk_task_holds', 'vk_task_entries', 'vk_comments', 'vk_checkpoints', 'vk_submissions', 'vk_reviews', 'vk_disputes', 'vk_transfers', 'vk_help_requests', 'vk_tips', 'vk_escrow_payouts', 'vk_escrows']) await db(table).whereIn('task_id', taskIds).del()
       await db('vk_jobs').whereIn('ref_id', taskIds).del()
@@ -210,6 +217,16 @@ function createWorld(name, db) {
   const wallet = async (agent) => (await call('GET', '/v1/wallet', { token: agent.key })).json.data
   const SUBMISSION = { summary: 'Translated; see the doc.', artifacts: [{ type: 'link', url: 'https://example.com/doc/1', note: 'translation' }] }
   const submit = (agent, taskId, summary = SUBMISSION.summary) => call('POST', `/v1/tasks/${taskId}/submit`, { token: agent.key, body: { ...SUBMISSION, summary } })
+  /** 上传一个交付文件（原始字节），返回接口响应。 */
+  async function uploadFile(agent, taskId, filename, content) {
+    const response = await fetch(`${api}/v1/tasks/${taskId}/files?filename=${encodeURIComponent(filename)}`, { method: 'POST', headers: { authorization: `Bearer ${agent.key}`, 'content-type': 'application/octet-stream' }, body: content })
+    return { status: response.status, json: await response.json() }
+  }
+  /** 下载一个交付文件；成功时返回正文文本。 */
+  async function downloadFile(agent, fileId) {
+    const response = await fetch(`${api}/v1/files/${fileId}`, { headers: { authorization: `Bearer ${agent.key}` } })
+    return { status: response.status, disposition: response.headers.get('content-disposition'), text: response.status === 200 ? await response.text() : null }
+  }
   const claim = (agent, taskId) => call('POST', `/v1/tasks/${taskId}/claim`, { token: agent.key })
   /** 按清单逐条验收；`failing` 是不通过的清单项 id。 */
   const review = (agent, taskId, action, ids, failing = [], extra = {}) => call('POST', `/v1/tasks/${taskId}/review`, {
@@ -217,5 +234,5 @@ function createWorld(name, db) {
     body: { action, checks: ids.map((id) => ({ id, pass: !failing.includes(id), reason: failing.includes(id) ? 'Not met yet.' : 'Looks good.' })), ...extra },
   })
 
-  return { db, results, check, call, admin, waitForEmail, createOwner, createGuild, createAgent, registerAgent, grantBudget, publish, waitForTask, wallet, submit, claim, review, cleanup }
+  return { db, results, check, call, admin, waitForEmail, createOwner, createGuild, createAgent, registerAgent, grantBudget, publish, waitForTask, wallet, submit, claim, review, uploadFile, downloadFile, cleanup }
 }
diff --git a/apps/voko-server/tools/scenarios/voko-alpha/company-agent.mjs b/apps/voko-server/tools/scenarios/voko-alpha/company-agent.mjs
index 2974e54..053d845 100644
--- a/apps/voko-server/tools/scenarios/voko-alpha/company-agent.mjs
+++ b/apps/voko-server/tools/scenarios/voko-alpha/company-agent.mjs
@@ -13,7 +13,7 @@ import { runScenario } from './_lib.mjs'
 loadDotenv({ path: fileURLToPath(new URL('../../../.env', import.meta.url)) })
 const agentDir = fileURLToPath(new URL('../../../../../tools/voko-company-agent/', import.meta.url))
 
-await runScenario('ca', async ({ db, check, call, admin, createOwner, createGuild, createAgent, publish, wallet, claim }) => {
+await runScenario('ca', async ({ db, check, call, admin, createOwner, createGuild, createAgent, publish, wallet, claim, uploadFile }) => {
   const alice = await createOwner('alice')
   const bob = await createOwner('bob')
   const guild = await createGuild('main', alice.user_id, { require_lead_approval: true })
@@ -24,12 +24,14 @@ await runScenario('ca', async ({ db, check, call, admin, createOwner, createGuil
   await call('PUT', `/api/voko/admin/guilds/${guild}/weekly-goal`, { token: adminToken, body: { weekly_goal: 1000 } })
 
   // 一份明显合格的提交在等公司 Agent 验收。
-  const acceptance = [{ id: 'c1', text: 'The summary says the article is finished.' }, { id: 'c2', text: 'The submission includes a link to the article.' }]
+  const acceptance = [{ id: 'c1', text: 'The summary says the article is finished.' }, { id: 'c2', text: 'The article is attached as a file and explains how to reset a password in numbered steps.' }]
   const task = (await publish(company, { title: 'Write a short how-to article', spec: 'Write a 300-word how-to article about resetting a password.', reward: 40, acceptance })).json.data
   await call('POST', `/api/voko/approvals/${task.id}`, { token: alice.token, body: { decision: 'approve' } })
   await claim(worker, task.id)
-  // 交付物的链接说明要与任务相符：公共库默认的说明是「translation」，真实模型会据此（正确地）判第二条不通过。
-  const delivered = await call('POST', `/v1/tasks/${task.id}/submit`, { token: worker.key, body: { summary: 'The article is finished. It is a 300-word how-to about resetting a password; the link to the article is attached.', artifacts: [{ type: 'link', url: 'https://example.com/articles/reset-password', note: 'The finished how-to article' }] } })
+  // 交付物是上传到平台的文件：公司 Agent 要下载它、读正文再判。
+  const article = '# How to reset your password\n\n1. Open Settings and choose Security.\n2. Click Reset password.\n3. Enter the code we email you, then type a new password twice.\n4. Sign in again with the new password.\n'
+  const file = await uploadFile(worker, task.id, 'reset-password.md', article)
+  const delivered = await call('POST', `/v1/tasks/${task.id}/submit`, { token: worker.key, body: { summary: 'The article is finished and attached as a file.', artifacts: [{ type: 'file', file_id: file.json.data.file_id, note: 'The finished how-to article' }] } })
   check('员工 Agent 提交', delivered.status === 200, delivered)
 
   const ran = spawnSync('node', ['agent.mjs', '--once'], {
diff --git a/apps/voko-server/tools/scenarios/voko-alpha/f2-execute.mjs b/apps/voko-server/tools/scenarios/voko-alpha/f2-execute.mjs
index 3284adb..b17e91d 100644
--- a/apps/voko-server/tools/scenarios/voko-alpha/f2-execute.mjs
+++ b/apps/voko-server/tools/scenarios/voko-alpha/f2-execute.mjs
@@ -4,7 +4,7 @@
  */
 import { runScenario } from './_lib.mjs'
 
-await runScenario('f2', async ({ db, check, call, waitForEmail, createOwner, createGuild, createAgent, grantBudget, publish, submit, claim }) => {
+await runScenario('f2', async ({ db, check, call, waitForEmail, createOwner, createGuild, createAgent, grantBudget, publish, submit, claim, uploadFile, downloadFile }) => {
   const alice = await createOwner('alice')
   const bob = await createOwner('bob')
   const guild = await createGuild('main', alice.user_id)
@@ -93,12 +93,29 @@ await runScenario('f2', async ({ db, check, call, waitForEmail, createOwner, cre
   const noPending = await call('POST', `/v1/tasks/${moving.id}/transfer/accept`, { token: taker.key })
   check('没有待确认转让时接受 → 409', noPending.status === 409, noPending)
 
-  // F2-07 交付物只接受链接；提交后进入待验收。
+  // F2-07 交付物：上传到平台的文件或 https 外链；提交后进入待验收。
   const delivering = tasks[2]
   const notLink = await call('POST', `/v1/tasks/${delivering.id}/submit`, { token: taker.key, body: { summary: 'done', artifacts: [{ type: 'file', url: 'https://example.com/a.zip' }] } })
   const httpLink = await call('POST', `/v1/tasks/${delivering.id}/submit`, { token: taker.key, body: { summary: 'done', artifacts: [{ type: 'link', url: 'http://example.com/a' }] } })
-  check('F2-07 非链接或非 https 交付物 → 400', notLink.status === 400 && httpLink.status === 400, { notLink, httpLink })
-  const submitted = await submit(taker, delivering.id)
+  const noArtifacts = await call('POST', `/v1/tasks/${delivering.id}/submit`, { token: taker.key, body: { summary: 'done', artifacts: [] } })
+  check('F2-07 格式不对的交付物、非 https 链接、没有交付物 → 400，提示先上传文件', notLink.status === 400 && httpLink.status === 400 && noArtifacts.status === 400 && noArtifacts.json.error.hint.includes('/files'), { notLink, httpLink, noArtifacts })
+  const article = '# How to reset a password\n\n1. Open Settings.\n2. Choose Reset password.\n'
+  const uploaded = await uploadFile(taker, delivering.id, '../../reset password.md', article)
+  check('上传交付文件 → file_id、去掉路径的文件名、大小与哈希', uploaded.status === 200 && uploaded.json.data.file_id.startsWith('f_') && uploaded.json.data.filename === 'reset password.md' && uploaded.json.data.size_bytes === Buffer.byteLength(article) && /^[0-9a-f]{64}$/.test(uploaded.json.data.sha256), uploaded)
+  const strangerUpload = await uploadFile(rival, delivering.id, 'x.md', 'x')
+  const emptyUpload = await uploadFile(taker, delivering.id, 'empty.md', '')
+  check('非持有人上传 → 403；空文件 → 422', strangerUpload.status === 403 && emptyUpload.status === 422, { strangerUpload, emptyUpload })
+  const rivalFile = await uploadFile(rival, working.id, 'mine.md', 'rival work')
+  const borrowed = await call('POST', `/v1/tasks/${delivering.id}/submit`, { token: taker.key, body: { summary: 'done', artifacts: [{ type: 'file', file_id: rivalFile.json.data.file_id }] } })
+  check('提交里引用别人或别的任务的文件 → 422', rivalFile.status === 200 && borrowed.status === 422, { borrowed })
+  const beforeSubmit = await downloadFile(publisher, uploaded.json.data.file_id)
+  check('上传者能下载自己的文件；别的成员取不到', (await downloadFile(taker, uploaded.json.data.file_id)).text === article && (await downloadFile(rival, uploaded.json.data.file_id)).status === 404, beforeSubmit)
+  const submitted = await call('POST', `/v1/tasks/${delivering.id}/submit`, { token: taker.key, body: { summary: 'The how-to article is attached.', artifacts: [{ type: 'file', file_id: uploaded.json.data.file_id, note: 'The article' }] } })
+  const seen = (await call('GET', `/v1/tasks/${delivering.id}`, { token: publisher.key })).json.data.submissions[0].artifacts[0]
+  const fetched = await downloadFile(publisher, uploaded.json.data.file_id)
+  check('发布方在任务详情里看到文件名与大小，并能下载到原文（以附件形式）', seen.type === 'file' && seen.filename === 'reset password.md' && seen.size_bytes === Buffer.byteLength(article) && fetched.text === article && fetched.disposition.startsWith('attachment'), { seen, fetched })
+  const lateUpload = await uploadFile(taker, delivering.id, 'late.md', 'late')
+  check('提交后不能再上传 → 409', lateUpload.status === 409, lateUpload)
   const publisherHome = await call('GET', '/v1/home', { token: publisher.key })
   check('F2-07 提交 → submitted，发布方 /home 的 to_review 出现', submitted.status === 200 && submitted.json.data.status === 'submitted' && typeof submitted.json.data.review_due === 'string' && publisherHome.json.data.to_review.some((t) => t.id === delivering.id), { submitted, to_review: publisherHome.json.data.to_review })
 
diff --git a/apps/voko-server/tools/scenarios/voko-alpha/f3-review-settle.mjs b/apps/voko-server/tools/scenarios/voko-alpha/f3-review-settle.mjs
index 1b8d81e..7e82c0d 100644
--- a/apps/voko-server/tools/scenarios/voko-alpha/f3-review-settle.mjs
+++ b/apps/voko-server/tools/scenarios/voko-alpha/f3-review-settle.mjs
@@ -107,6 +107,28 @@ await runScenario('f3', async ({ db, check, call, admin, createOwner, createGuil
   const contestPayouts = await db('vk_escrow_payouts').where({ task_id: contest.id })
   check('F3-05 选赢家 → 赢家全额 40，其他人无流水', won.status === 200 && won.json.data.status === 'settled' && (await wallet(taker)).available === 291 && (await wallet(helper)).available === helperBefore && contestPayouts.length === 1, { won, contestPayouts })
 
+  // 未结算前持有人在任何状态都能放弃：已提交、返工中、仲裁中。
+  const fickle = (await publish(publisher, { reward: 20, acceptance: items })).json.data
+  await claim(taker, fickle.id)
+  await submit(taker, fickle.id)
+  const afterSubmit = await call('POST', `/v1/tasks/${fickle.id}/release`, { token: taker.key })
+  const lateReview = await review(publisher, fickle.id, 'accept', ids)
+  check('已提交后放弃 → 回到 open，发布方再验收 → 409', afterSubmit.status === 200 && afterSubmit.json.data.status === 'open' && afterSubmit.json.data.holder_agent_id === null && lateReview.status === 409, { afterSubmit, lateReview })
+  await claim(helper, fickle.id)
+  await submit(helper, fickle.id)
+  await review(publisher, fickle.id, 'reject', ids, ['c1'], { reason: 'Not natural.' })
+  const fromRework = await call('POST', `/v1/tasks/${fickle.id}/release`, { token: helper.key })
+  check('返工中放弃 → 回到 open，返工次数清零', fromRework.status === 200 && fromRework.json.data.status === 'open' && fromRework.json.data.rework_count === 0, fromRework)
+  await claim(taker, fickle.id)
+  await submit(taker, fickle.id)
+  await call('POST', `/v1/tasks/${fickle.id}/dispute`, { token: taker.key })
+  const fromDispute = await call('POST', `/v1/tasks/${fickle.id}/release`, { token: taker.key })
+  const closedDispute = await db('vk_disputes').where({ task_id: fickle.id }).first()
+  check('仲裁中放弃 → 回到 open，争议关闭，托管仍冻结', fromDispute.status === 200 && fromDispute.json.data.status === 'open' && closedDispute.status === 'resolved' && closedDispute.resolution.outcome === 'released' && (await db('vk_escrows').where({ task_id: fickle.id }).first()).status === 'held', { fromDispute, closedDispute })
+  const settledRelease = await call('POST', `/v1/tasks/${first.id}/release`, { token: taker.key })
+  check('已结算的任务不能放弃 → 409', settledRelease.status === 409, settledRelease)
+  check('撤回无人在做的任务，托管退回', (await call('POST', `/v1/tasks/${fickle.id}/cancel`, { token: publisher.key })).json.data.status === 'cancelled')
+
   // F3-06 打赏：打赏人减、收款人加；重放不重复；余额不足 → 402；未结算任务与打赏自己被拒。
   const tipKey = randomUUID()
   const tipperBefore = (await wallet(helper)).available
diff --git a/packages/voko-exchange/src/db/tables/index.cjs b/packages/voko-exchange/src/db/tables/index.cjs
index 07d9fe5..6894ec4 100644
--- a/packages/voko-exchange/src/db/tables/index.cjs
+++ b/packages/voko-exchange/src/db/tables/index.cjs
@@ -17,6 +17,7 @@ const tableModules = [
   require('./vk_events.cjs'),
   require('./vk_jobs.cjs'),
   require('./vk_agent_titles.cjs'),
+  require('./vk_files.cjs'),
 ]
 
 const targetTables = tableModules.map(({ tableName, buildTable }) => [tableName, buildTable])
diff --git a/packages/voko-exchange/src/db/tables/vk_files.cjs b/packages/voko-exchange/src/db/tables/vk_files.cjs
new file mode 100644
index 0000000..a644f82
--- /dev/null
+++ b/packages/voko-exchange/src/db/tables/vk_files.cjs
@@ -0,0 +1,15 @@
+const tableName = 'vk_files'
+
+function buildTable(t) {
+  t.string('id', 64).primary()
+  t.string('task_id', 64).notNullable()
+  t.string('agent_id', 64).notNullable()
+  t.string('filename', 255).notNullable()
+  t.integer('size_bytes').unsigned().notNullable()
+  t.string('sha256', 64).notNullable()
+  t.datetime('created_at', { precision: 3 }).notNullable()
+  t.index(['task_id', 'agent_id'], 'idx_vk_files_task_agent')
+  t.check('size_bytes > 0', [], 'ck_vk_files_size')
+}
+
+module.exports = { tableName, buildTable }
diff --git a/packages/voko-exchange/src/db/tables/vk_submissions.cjs b/packages/voko-exchange/src/db/tables/vk_submissions.cjs
index 1927bc7..a65c7e8 100644
--- a/packages/voko-exchange/src/db/tables/vk_submissions.cjs
+++ b/packages/voko-exchange/src/db/tables/vk_submissions.cjs
@@ -9,7 +9,7 @@ function buildTable(t) {
   t.json('artifacts').notNullable()
   t.datetime('created_at', { precision: 3 }).notNullable()
   t.unique(['task_id', 'agent_id', 'round'], { indexName: 'uq_vk_submissions_task_agent_round' })
-  t.check('round between 1 and 3', [], 'ck_vk_submissions_round')
+  t.check('round >= 1', [], 'ck_vk_submissions_round')
 }
 
 module.exports = { tableName, buildTable }
diff --git a/packages/voko-exchange/src/files.js b/packages/voko-exchange/src/files.js
new file mode 100644
index 0000000..5a6069a
--- /dev/null
+++ b/packages/voko-exchange/src/files.js
@@ -0,0 +1,115 @@
+import { createHash, randomUUID } from 'node:crypto'
+
+import { taskFromRow } from './task.js'
+
+const FILES = 'vk_files'
+export const MAX_FILE_BYTES = 10 * 1024 * 1024
+const MAX_FILES_PER_AGENT_TASK = 20
+/** 裁判（大模型）能直接读的文本类文件：按扩展名判断，且不超过这个大小。 */
+const TEXT_EXTENSIONS = /\.(md|markdown|txt|csv|json|html?|xml|ya?ml)$/i
+const MAX_TEXT_BYTES = 64 * 1024
+
+/**
+ * 交付文件：Agent 把交付物上传到平台，提交时引用；发布方（及平台裁判）下载查看。
+ *
+ * @param {{
+ *   db: import('knex').Knex,
+ *   store: { put(file_id: string, body: Buffer): Promise<void>, get(file_id: string): Promise<Buffer> },
+ * }} deps `store` 是文件内容的存储（本地磁盘或对象存储），由 composition root 注入
+ */
+export function createFiles({ db, store }) {
+  if (typeof db !== 'function') throw new Error('createFiles: db is required')
+
+  /**
+   * 上传一个交付文件。只有正在做这个任务的 Agent（计件活的持有人、擂台赛的参赛者）可以上传。
+   * @param {object} _ctx
+   * @param {{ agent: import('./agents.js').Agent, task_id: string, filename: string, body: Buffer }} input
+   * @returns {Promise<{ ok: true, file: { file_id: string, filename: string, size_bytes: number, sha256: string } } | { ok: false, code: 'not_found'|'forbidden'|'state_conflict'|'rule_violation', hint: string }>}
+   */
+  async function upload(_ctx, { agent, task_id, filename, body }) {
+    if (body.length === 0) return refuse('rule_violation', 'The file is empty.')
+    if (body.length > MAX_FILE_BYTES) return refuse('rule_violation', `The file is larger than ${MAX_FILE_BYTES} bytes.`)
+    const row = await db('vk_tasks').where({ id: task_id }).first()
+    if (row === undefined) return refuse('not_found', `Task not found: ${task_id}`)
+    const task = taskFromRow(row)
+    if (task.guild_id !== agent.guild_id) return refuse('forbidden', 'You are not a member of this guild.')
+    switch (task.status) {
+      case 'claimed':
+      case 'rework':
+        if (task.holder_agent_id !== agent.id) return refuse('forbidden', 'Only the current holder can upload deliverables for this task.')
+        break
+      case 'in_contest':
+        if ((await db('vk_task_entries').where({ task_id, agent_id: agent.id }).first('id')) === undefined) return refuse('forbidden', 'Enter the contest before uploading deliverables.')
+        break
+      case 'pending_approval':
+      case 'open':
+      case 'submitted':
+      case 'reviewing':
+      case 'disputed':
+      case 'settled':
+      case 'cancelled':
+      case 'refunded':
+        return refuse('state_conflict', `Task is ${task.status}; deliverables can only be uploaded while you are working on it.`)
+      default:
+        throw new Error(`Unhandled status: ${task.status}, id: ${task.id}`)
+    }
+    const count = await db(FILES).where({ task_id, agent_id: agent.id }).count({ n: '*' }).first()
+    if (Number(count.n) >= MAX_FILES_PER_AGENT_TASK) return refuse('rule_violation', `At most ${MAX_FILES_PER_AGENT_TASK} files per task.`)
+    const file = { id: `f_${randomUUID()}`, task_id, agent_id: agent.id, filename: safeFilename(filename), size_bytes: body.length, sha256: createHash('sha256').update(body).digest('hex'), created_at: new Date() }
+    // 先存内容再记元数据：记了元数据就一定取得到内容。
+    await store.put(file.id, body)
+    await db(FILES).insert(file)
+    return { ok: true, file: { file_id: file.id, filename: file.filename, size_bytes: file.size_bytes, sha256: file.sha256 } }
+  }
+
+  /**
+   * 下载。上传者本人随时可取；发布方在任务不处于擂台赛封存期时可取；其他人按不存在处理。
+   * @param {object} _ctx
+   * @param {{ agent: import('./agents.js').Agent, file_id: string }} input
+   * @returns {Promise<{ ok: true, filename: string, body: Buffer } | { ok: false, code: 'not_found', hint: string }>}
+   */
+  async function download(_ctx, { agent, file_id }) {
+    const file = await db(FILES).where({ id: file_id }).first()
+    if (file === undefined) return refuse('not_found', `File not found: ${file_id}`)
+    if (file.agent_id !== agent.id) {
+      const task = await db('vk_tasks').where({ id: file.task_id }).first('publisher_agent_id', 'status')
+      if (task.publisher_agent_id !== agent.id || task.status === 'in_contest') return refuse('not_found', `File not found: ${file_id}`)
+    }
+    return { ok: true, filename: file.filename, body: await store.get(file.id) }
+  }
+
+  /**
+   * 给平台裁判读的正文：小的文本类文件返回内容，其余返回 null（裁判只能看到文件名与大小）。
+   * @param {string} file_id
+   * @returns {Promise<string|null>}
+   */
+  async function textOf(file_id) {
+    const file = await db(FILES).where({ id: file_id }).first('id', 'filename', 'size_bytes')
+    if (file === undefined) throw new Error(`vk_files row missing, id: ${file_id}`)
+    if (!TEXT_EXTENSIONS.test(file.filename) || file.size_bytes > MAX_TEXT_BYTES) return null
+    return (await store.get(file.id)).toString('utf8')
+  }
+
+  return { upload, download, textOf }
+}
+
+/**
+ * 只保留文件名本身：去掉路径与控制字符，限制长度。文件名只用于展示与下载时的建议名，不参与存储路径。
+ * @param {string} filename
+ * @returns {string}
+ */
+function safeFilename(filename) {
+  // eslint-disable-next-line no-control-regex
+  const base = filename.split(/[\\/]/).pop().replace(/[\u0000-\u001f\u007f"]/g, '').trim()
+  return (base === '' || base === '.' || base === '..' ? 'file' : base).slice(-200)
+}
+
+/**
+ * @template {string} C
+ * @param {C} code
+ * @param {string} hint
+ * @returns {{ ok: false, code: C, hint: string }}
+ */
+function refuse(code, hint) {
+  return { ok: false, code, hint }
+}
diff --git a/packages/voko-exchange/src/index.js b/packages/voko-exchange/src/index.js
index 6146c75..57eb202 100644
--- a/packages/voko-exchange/src/index.js
+++ b/packages/voko-exchange/src/index.js
@@ -12,6 +12,7 @@ export { createTasks } from './tasks.js'
 export { createEvents } from './events.js'
 export { createJobs } from './jobs.js'
 export { createHelp } from './help.js'
+export { createFiles, MAX_FILE_BYTES } from './files.js'
 export { createGame } from './game.js'
 export { levelForXp, weekStart, MAX_LEVEL } from './level.js'
 export { createJudge } from './judge.js'
diff --git a/packages/voko-exchange/src/split-relay.js b/packages/voko-exchange/src/split-relay.js
index ff79f05..c9a489c 100644
--- a/packages/voko-exchange/src/split-relay.js
+++ b/packages/voko-exchange/src/split-relay.js
@@ -1,6 +1,6 @@
 /**
  * 接力分配（2026-10-09 定：平分）。参与分配的人 = 最终提交者 + 所有留下过有效检查点后离开的前任
- * （has_valid_checkpoint 且 end_reason ∈ timeout / released / transferred）；同一 Agent 多次持有只算一份。
+ * （has_valid_checkpoint 且持有已结束：timeout / released / transferred，或提交后又放弃）；同一 Agent 多次持有只算一份。
  * 赏金按人数平分，除不尽的余数归最终提交者。各笔之和必须等于 reward。
  *
  * @param {number} reward 正整数
@@ -13,12 +13,13 @@ export function splitRelayPayout(reward, holds, final_agent_id) {
   const relays = new Set()
   for (const hold of holds) {
     switch (hold.end_reason) {
+      // 提交过又放弃的前任（其持有以 submitted 结束）同样算留下过工作。
       case 'released':
       case 'timeout':
       case 'transferred':
+      case 'submitted':
         if (hold.has_valid_checkpoint && hold.agent_id !== final_agent_id) relays.add(hold.agent_id)
         break
-      case 'submitted':
       case null:
         break
       default:
diff --git a/packages/voko-exchange/src/tasks.js b/packages/voko-exchange/src/tasks.js
index 1b786e5..93ae849 100644
--- a/packages/voko-exchange/src/tasks.js
+++ b/packages/voko-exchange/src/tasks.js
@@ -42,9 +42,10 @@ const JOBS = 'vk_jobs'
  *     spentToday(ctx: object, trx: import('knex').Knex, input: { wallet_user_id: string, now: Date }): Promise<number>,
  *   },
  *   judge: ReturnType<typeof import('./judge.js').createJudge>,
- * }} deps
+ *   fileText(file_id: string): Promise<string|null>,
+ * }} deps `fileText` 取交付文件的正文给裁判读（非文本或太大时为 null）
  */
-export function createTasks({ db, agents, escrow, judge }) {
+export function createTasks({ db, agents, escrow, judge, fileText }) {
   if (typeof db !== 'function') throw new Error('createTasks: db is required')
 
   /**
@@ -164,7 +165,8 @@ export function createTasks({ db, agents, escrow, judge }) {
   async function apply(ctx, trx, task, action, actor, idempotency_key, now, record) {
     const guild = await guildRow(trx, task.guild_id)
     const publisher = await agents.getById(ctx, trx, { agent_id: task.publisher_agent_id })
-    const result = transition({ task, guild, publisher_owner_user_id: /** @type {string} */ (publisher.owner_user_id) }, action, actor, now)
+    const entries = await trx(ENTRIES).where({ task_id: task.id }).count({ n: '*' }).first()
+    const result = transition({ task, guild, publisher_owner_user_id: /** @type {string} */ (publisher.owner_user_id), entry_count: Number(entries.n) }, action, actor, now)
     if (!result.ok) return result
     const next = result.task
     await trx(TASKS).where({ id: task.id }).update({
@@ -194,6 +196,17 @@ export function createTasks({ db, agents, escrow, judge }) {
         case 'entry_add':
           await trx(ENTRIES).insert({ id: `en_${randomUUID()}`, task_id: task.id, agent_id: effect.agent_id, created_at: now })
           break
+        case 'entry_remove':
+          // 退赛：报名与（封存中的）提交一并撤掉。
+          await trx(SUBMISSIONS).where({ task_id: task.id, agent_id: effect.agent_id }).del()
+          await trx(ENTRIES).where({ task_id: task.id, agent_id: effect.agent_id }).del()
+          break
+        case 'dispute_close': {
+          // 持有人放弃，争议不再需要裁决；记为由该 Agent 的主人关闭。
+          const releasing = await agents.getById(ctx, trx, { agent_id: effect.agent_id })
+          await trx(DISPUTES).where({ task_id: task.id }).whereNot({ status: 'resolved' }).update({ status: 'resolved', resolution: JSON.stringify({ outcome: 'released', agent_id: effect.agent_id }), resolved_by_user_id: releasing.owner_user_id, resolved_at: now })
+          break
+        }
         case 'escrow_topup':
           await escrow.topup(ctx, trx, { task_id: task.id, amount: effect.amount, idempotency_key: /** @type {string} */ (idempotency_key) })
           break
@@ -373,23 +386,37 @@ export function createTasks({ db, agents, escrow, judge }) {
   }
 
   /**
-   * 提交交付物。计件活每轮一份（第 n 次返工是第 n+1 轮）；擂台赛每个参赛者一份，截止前封存。
+   * 提交交付物。计件活每次提交一轮（返工重交、放弃后再接再交都递增）；擂台赛每个参赛者一份，截止前封存。
    * @param {object} ctx
-   * @param {{ agent: Agent, task_id: string, summary: string, artifacts: Array<{ type: 'link', url: string, note?: string }> }} input
+   * @param {{ agent: Agent, task_id: string, summary: string, artifacts: Array<{ type: 'link', url: string, note?: string } | { type: 'file', file_id: string, note?: string }> }} input 文件须是本人为这个任务上传的
    */
   async function submit(ctx, { agent, task_id, summary, artifacts }) {
+    /** @type {Array<Record<string, unknown>>} */
+    let stored = []
     return act(ctx, {
       agent,
       task_id,
       action: { type: 'submit' },
       async prepare(trx, task) {
+        const ids = artifacts.filter((artifact) => artifact.type === 'file').map((artifact) => artifact.file_id)
+        const files = ids.length === 0 ? [] : await trx('vk_files').whereIn('id', ids).where({ task_id, agent_id: agent.id }).select('id', 'filename', 'size_bytes')
+        const unknown = ids.filter((id) => !files.some((file) => file.id === id))
+        if (unknown.length > 0) return refuse('rule_violation', `These file_ids are not files you uploaded for this task: ${unknown.join(', ')}.`)
+        // 文件类交付物连同文件名与大小一起记进提交，之后展示不必再查文件表。
+        stored = artifacts.map((artifact) => {
+          if (artifact.type !== 'file') return artifact
+          const file = files.find((item) => item.id === artifact.file_id)
+          return { ...artifact, filename: file.filename, size_bytes: file.size_bytes }
+        })
         if (task.template !== 'contest') return null
         const existing = await trx(SUBMISSIONS).where({ task_id, agent_id: agent.id }).first('id')
         return existing === undefined ? null : refuse('state_conflict', 'You have already submitted to this contest.')
       },
       async record(trx, before, _after, now) {
         const id = `s_${randomUUID()}`
-        await trx(SUBMISSIONS).insert({ id, task_id, agent_id: agent.id, round: before.template === 'contest' ? 1 : before.rework_count + 1, summary, artifacts: JSON.stringify(artifacts), created_at: now })
+        // 轮次按这个 Agent 在这个任务上已有的提交数递增：返工重交、放弃后再接再交都各占一轮。
+        const prior = await trx(SUBMISSIONS).where({ task_id, agent_id: agent.id }).max({ round: 'round' }).first()
+        await trx(SUBMISSIONS).insert({ id, task_id, agent_id: agent.id, round: (prior.round ?? 0) + 1, summary, artifacts: JSON.stringify(stored), created_at: now })
         return { submission_id: id }
       },
     })
@@ -567,6 +594,14 @@ export function createTasks({ db, agents, escrow, judge }) {
   }
 
   /**
+   * 给裁判看的交付物：文本类小文件附上正文，其余只有文件名与大小。
+   * @param {Array<Record<string, any>>} artifacts
+   */
+  async function readable(artifacts) {
+    return Promise.all(artifacts.map(async (artifact) => (artifact.type === 'file' ? { type: 'file', filename: artifact.filename, size_bytes: artifact.size_bytes, note: artifact.note, content: await fileText(artifact.file_id) } : artifact)))
+  }
+
+  /**
    * worker：擂台赛验收窗口到期，由大模型按清单选赢家后结算；没有提交或无人全部通过则退款。
    * 模型调用在事务外进行（不占任务行锁）；随后的状态机会重新检查任务状态与到期时间。
    * @param {object} ctx
@@ -580,7 +615,7 @@ export function createTasks({ db, agents, escrow, judge }) {
     const submissions = await db(SUBMISSIONS).where({ task_id }).select('id', 'agent_id', 'summary', 'artifacts')
     const verdict = submissions.length === 0
       ? { winner_submission_id: null, checks: [], reason: 'No submissions.' }
-      : await judge.pickContestWinner({ task, acceptance: await acceptanceOf(db, task_id), submissions: submissions.map((item) => ({ id: item.id, summary: item.summary, artifacts: item.artifacts })) })
+      : await judge.pickContestWinner({ task, acceptance: await acceptanceOf(db, task_id), submissions: await Promise.all(submissions.map(async (item) => ({ id: item.id, summary: item.summary, artifacts: await readable(item.artifacts) }))) })
     const winner = submissions.find((item) => item.id === verdict.winner_submission_id)
     await actAsWorker(ctx, {
       task_id,
@@ -612,7 +647,7 @@ export function createTasks({ db, agents, escrow, judge }) {
     const proposal = await judge.proposeArbitration({
       task,
       acceptance: await acceptanceOf(db, task_id),
-      submissions,
+      submissions: await Promise.all(submissions.map(async (item) => ({ ...item, artifacts: await readable(item.artifacts) }))),
       reviews: reviews.map((item) => ({ action: item.action, reason: item.reason, checks: checks.filter((check) => check.review_id === item.id).map((check) => ({ id: check.item_key, pass: check.pass === 1, reason: check.reason })) })),
       comments,
     })
diff --git a/packages/voko-exchange/src/transition.js b/packages/voko-exchange/src/transition.js
index 9433045..25fa825 100644
--- a/packages/voko-exchange/src/transition.js
+++ b/packages/voko-exchange/src/transition.js
@@ -47,7 +47,8 @@ const HOUR_MS = 3600_000
  *   task: Task,
  *   guild: { checkpoint_interval_sec: number, piece_review_window_sec: number, contest_review_window_sec: number },
  *   publisher_owner_user_id: string,
- * }} TaskState 任务行 + 所属公会的时间规则 + 发布方 Agent 的主人，由 service 在事务内读出。
+ *   entry_count: number,
+ * }} TaskState 任务行 + 所属公会的时间规则 + 发布方 Agent 的主人 + 擂台赛当前报名数，由 service 在事务内读出。
  *
  * @typedef {{ kind: 'agent', agent_id: string, owner_user_id: string, max_rarity: number, active_hold_count: number, is_entrant: boolean }} AgentActor
  * @typedef {AgentActor | { kind: 'lead', user_id: string } | { kind: 'operator', user_id: string } | { kind: 'worker' }} Actor
@@ -66,6 +67,8 @@ const HOUR_MS = 3600_000
  *   { type: 'hold_end', reason: 'submitted'|'released'|'timeout'|'transferred' } |
  *   { type: 'hold_checkpoint' } |
  *   { type: 'entry_add', agent_id: string } |
+ *   { type: 'entry_remove', agent_id: string } |
+ *   { type: 'dispute_close', agent_id: string } |
  *   { type: 'escrow_topup', amount: number } |
  *   { type: 'escrow_refund' } |
  *   { type: 'escrow_settle', winner_agent_id: string } |
@@ -227,6 +230,11 @@ const TRANSITIONS = {
       // 提交封存到截止，不通知发布方。
       return ok(task, [])
     },
+    // 参赛者退赛：撤掉自己的报名与提交；最后一个人退出后任务回到 open。
+    release({ task, entry_count }, _action, actor) {
+      if (actor.kind !== 'agent' || !actor.is_entrant) return notAllowed('Only an entrant can withdraw from a contest.')
+      return ok(entry_count <= 1 ? { ...task, status: 'open' } : task, [{ type: 'entry_remove', agent_id: actor.agent_id }])
+    },
     contest_close(state, _action, actor, now) {
       const { task } = state
       if (actor.kind !== 'worker') return notAllowed('Only the platform can close a contest.')
@@ -260,6 +268,7 @@ const TRANSITIONS = {
       return ok({ ...task, status: 'rework', rework_count: task.rework_count + 1, review_due_at: null }, [event('task.rejected', holder)])
     },
     dispute: openDispute,
+    release: holderRelease,
   },
 
   reviewing: {
@@ -287,6 +296,7 @@ const TRANSITIONS = {
       return ok(...submitted(state, now, []))
     },
     dispute: openDispute,
+    release: holderRelease,
   },
 
   disputed: {
@@ -303,6 +313,12 @@ const TRANSITIONS = {
           throw new Error(`Unhandled outcome: ${action.outcome}, id: ${task.id}`)
       }
     },
+    // 持有人在仲裁中放弃：争议随之关闭，任务回到看板。
+    release({ task }, _action, actor, now) {
+      if (!isHolder(task, actor) || actor.kind !== 'agent') return notAllowed('Only the current holder can release.')
+      const reopened = reopen(task, now)
+      return ok(reopened, [{ type: 'dispute_close', agent_id: actor.agent_id }, ...releaseEffects(task, reopened, 'released')])
+    },
   },
 
   settled: {},
@@ -312,6 +328,15 @@ const TRANSITIONS = {
 
 if (Object.keys(TRANSITIONS).length !== TASK_STATUSES.length) throw new Error('TRANSITIONS must cover every task status')
 
+/**
+ * 持有人放弃已提交或返工中的任务：只要还没结算，都可以释放回看板。
+ * @type {Handler}
+ */
+function holderRelease({ task }, _action, actor, now) {
+  if (!isHolder(task, actor)) return notAllowed('Only the current holder can release.')
+  return released(task, 'released', now)
+}
+
 /** @type {Handler} */
 function openDispute({ task }, _action, actor, now) {
   if (actor.kind !== 'agent') return notAllowed('Only the publisher or a taker can open a dispute.')
@@ -381,7 +406,7 @@ function released(task, reason, now) {
 }
 
 /**
- * 任务回到 open。若此时已过截止，按原先给的工期（created_at → deadline_at）从现在起重新计时，
+ * 任务回到 open（未结算前，持有人在任何状态都可以放弃）。若此时已过截止，按原先给的工期（created_at → deadline_at）从现在起重新计时，
  * 否则任务既接不了也不会过期，会卡死。
  * @param {Task} task
  * @param {Date} now
@@ -389,7 +414,8 @@ function released(task, reason, now) {
  */
 function reopen(task, now) {
   const deadline = now < task.deadline_at ? task.deadline_at : new Date(now.getTime() + (task.deadline_at.getTime() - task.created_at.getTime()))
-  return { ...task, status: 'open', deadline_at: deadline, holder_agent_id: null, next_checkpoint_due_at: null, missed_checkpoints: 0 }
+  // 新接手的人从零开始计返工次数。
+  return { ...task, status: 'open', deadline_at: deadline, holder_agent_id: null, next_checkpoint_due_at: null, missed_checkpoints: 0, rework_count: 0, review_due_at: null }
 }
 
 /**
diff --git a/packages/voko-exchange/test/split-relay.test.js b/packages/voko-exchange/test/split-relay.test.js
index d497abe..1a6421d 100644
--- a/packages/voko-exchange/test/split-relay.test.js
+++ b/packages/voko-exchange/test/split-relay.test.js
@@ -42,6 +42,13 @@ describe('SM-02 splitRelayPayout', () => {
     expect(splitRelayPayout(2, holds, 'b')).toEqual([{ agent_id: 'b', amount: 2, kind: 'winner' }])
   })
 
+  it('提交后又放弃的前任也参与平分', () => {
+    expect(splitRelayPayout(100, [hold('a', 'submitted', true), hold('b', 'submitted', true)], 'b')).toEqual([
+      { agent_id: 'b', amount: 50, kind: 'winner' },
+      { agent_id: 'a', amount: 50, kind: 'relay_share' },
+    ])
+  })
+
   it('全部结束原因都被处理；未知原因直接 throw', () => {
     for (const reason of ['submitted', 'released', 'timeout', 'transferred', null]) expect(() => splitRelayPayout(10, [hold('a', reason, true)], 'b')).not.toThrow()
     expect(() => splitRelayPayout(10, [hold('a', 'vanished', true)], 'b')).toThrow(/Unhandled end_reason: vanished/)
diff --git a/packages/voko-exchange/test/transition.test.js b/packages/voko-exchange/test/transition.test.js
index 34233e2..d8203a7 100644
--- a/packages/voko-exchange/test/transition.test.js
+++ b/packages/voko-exchange/test/transition.test.js
@@ -44,7 +44,7 @@ function stateFor(status, template = TEMPLATE_OF[status] ?? 'piecework', overrid
     updated_at: null,
     ...overrides,
   })
-  return { task, guild, publisher_owner_user_id: 'u_pub' }
+  return { task, guild, publisher_owner_user_id: 'u_pub', entry_count: 1 }
 }
 
 const TEMPLATE_OF = { in_contest: 'contest', reviewing: 'contest' }
@@ -84,11 +84,11 @@ const EXPECTED = {
   pending_approval: { approve: 'open', reject_approval: 'cancelled' },
   open: { claim: 'claimed', enter: 'in_contest', cancel: 'cancelled', open_expire: 'cancelled', edit: 'open' },
   claimed: { checkpoint: 'claimed', checkpoint_miss: 'claimed', release: 'open', hold_timeout: 'open', transfer_accept: 'claimed', submit: 'submitted' },
-  in_contest: { enter: 'in_contest', submit: 'in_contest', contest_close: 'reviewing' },
-  submitted: { accept: 'settled', reject: 'rework', review_auto_accept: 'settled', dispute: 'disputed' },
+  in_contest: { enter: 'in_contest', submit: 'in_contest', release: 'open', contest_close: 'reviewing' },
+  submitted: { accept: 'settled', reject: 'rework', review_auto_accept: 'settled', dispute: 'disputed', release: 'open' },
   reviewing: { select_winner: 'settled', review_auto_accept: 'settled', dispute: 'disputed' },
-  rework: { submit: 'submitted', dispute: 'disputed' },
-  disputed: { resolve: 'settled' },
+  rework: { submit: 'submitted', dispute: 'disputed', release: 'open' },
+  disputed: { resolve: 'settled', release: 'open' },
   settled: {},
   cancelled: {},
   refunded: {},
@@ -109,7 +109,7 @@ describe('SM-01 transition()：11 个状态 × 全部动作', () => {
     for (const type of TASK_ACTIONS) {
       const expected = EXPECTED[status][type]
       it(`${status} × ${type} → ${expected ?? 'state_conflict'}`, () => {
-        const actor = status === 'in_contest' && type === 'submit' ? entrant : ACTOR_OF[type]
+        const actor = status === 'in_contest' && (type === 'submit' || type === 'release') ? entrant : ACTOR_OF[type]
         // open 的 enter 只对擂台赛成立；计件活 enter 的规则错误在下面单独断言。
         const template = status === 'open' && type === 'enter' ? 'contest' : undefined
         const result = run(stateFor(status, template), type, actor)
@@ -180,6 +180,22 @@ describe('SM-01 副作用与平台规则', () => {
     expect(effectTypes(result)).toEqual(['hold_end', 'task.released', 'task.released'])
   })
 
+  it('未结算前持有人在任何状态都能放弃：返工次数清零、验收窗口清空；结算后不行', () => {
+    for (const status of ['claimed', 'rework', 'submitted', 'disputed']) {
+      const result = run(stateFor(status, 'piecework', { deadline_at: FUTURE, rework_count: status === 'claimed' ? 0 : 2 }), 'release')
+      expect(result.task, status).toMatchObject({ status: 'open', holder_agent_id: null, rework_count: 0, review_due_at: null })
+    }
+    expect(effectTypes(run(stateFor('disputed', 'piecework', { deadline_at: FUTURE }), 'release'))).toEqual(['dispute_close', 'hold_end', 'task.released', 'task.released'])
+    for (const status of ['settled', 'cancelled', 'refunded']) expect(run(stateFor(status), 'release')).toMatchObject({ ok: false, code: 'state_conflict' })
+  })
+
+  it('擂台赛退赛：还有别人时仍在比赛中，最后一人退出回到 open', () => {
+    const lastOne = run(stateFor('in_contest'), 'release', entrant)
+    expect(lastOne).toMatchObject({ ok: true, task: { status: 'open' }, effects: [{ type: 'entry_remove', agent_id: 'ag_entrant' }] })
+    expect(run({ ...stateFor('in_contest'), entry_count: 3 }, 'release', entrant).task.status).toBe('in_contest')
+    expect(run(stateFor('in_contest'), 'release', taker)).toMatchObject({ ok: false, code: 'forbidden' })
+  })
+
   it('未到期的 worker 动作是过时 job，返回 state_conflict', () => {
     expect(run(stateFor('open', 'piecework', { deadline_at: FUTURE }), 'open_expire')).toMatchObject({ ok: false, code: 'state_conflict' })
     expect(run(stateFor('claimed', 'piecework', { deadline_at: FUTURE }), 'hold_timeout')).toMatchObject({ ok: false, code: 'state_conflict' })
diff --git a/tools/voko-company-agent/agent.mjs b/tools/voko-company-agent/agent.mjs
index 31fb2d6..99041be 100644
--- a/tools/voko-company-agent/agent.mjs
+++ b/tools/voko-company-agent/agent.mjs
@@ -14,7 +14,7 @@
 import { createHash } from 'node:crypto'
 import { readFileSync } from 'node:fs'
 
-const SUPPORTED_SKILL_VERSION = '0.2.1'
+const SUPPORTED_SKILL_VERSION = '0.3.0'
 const config = {
   api: required('VOKO_API_BASE').replace(/\/$/, ''),
   key: required('VOKO_API_KEY'),
@@ -71,6 +71,24 @@ async function voko(method, path, opts = {}) {
   throw error
 }
 
+const TEXT_FILE = /\.(md|markdown|txt|csv|json|html?|xml|ya?ml)$/i
+const MAX_READ_BYTES = 64 * 1024
+
+/**
+ * 把一份提交的交付物整理成模型能读的样子：小的文本文件下载后附上正文，其余只给文件名与大小；外链原样给出。
+ * @param {Array<Record<string, any>>} artifacts
+ */
+async function readArtifacts(artifacts) {
+  return Promise.all(artifacts.map(async (artifact) => {
+    if (artifact.type !== 'file') return artifact
+    const described = { type: 'file', filename: artifact.filename, size_bytes: artifact.size_bytes, note: artifact.note }
+    if (!TEXT_FILE.test(artifact.filename) || artifact.size_bytes > MAX_READ_BYTES) return described
+    const response = await fetch(`${config.api}/files/${artifact.file_id}`, { headers: { authorization: `Bearer ${config.key}` } })
+    if (!response.ok) throw new Error(`GET /files/${artifact.file_id} → ${response.status}`)
+    return { ...described, content: await response.text() }
+  }))
+}
+
 /**
  * 让大模型按给定说明处理一份数据，返回解析后的 JSON。
  * @param {string} instructions
@@ -116,9 +134,9 @@ async function reviewPiecework(task) {
   const submission = task.submissions.at(-1)
   if (submission === undefined) return
   const verdict = await askModel(
-    'You are reviewing a deliverable for a task you published. Judge the submission against every acceptance item, strictly and fairly, using only what the submission states and links. '
+    'You are reviewing a deliverable for a task you published. Judge the submission against every acceptance item, strictly and fairly, using the summary and the content of the attached files. '
       + 'Reply as {"checks":[{"id":"<acceptance item id>","pass":true|false,"reason":"one specific sentence"}]} with exactly one entry per acceptance item.',
-    { task: { title: task.title, spec: task.spec }, acceptance: task.acceptance, submission: { summary: submission.summary, artifacts: submission.artifacts } },
+    { task: { title: task.title, spec: task.spec }, acceptance: task.acceptance, submission: { summary: submission.summary, artifacts: await readArtifacts(submission.artifacts) } },
   )
   const checks = validChecks(verdict.checks, task.acceptance)
   if (checks === null) return log('skip review: model output did not cover the checklist', { task_id: task.id })
@@ -134,7 +152,7 @@ async function reviewContest(task) {
   const verdict = await askModel(
     'You are judging a contest you published. Judge every submission against every acceptance item. Only a submission passing all items qualifies. Pick the best qualifying submission, or null if none qualifies. '
       + 'Reply as {"submissions":[{"submission_id":"...","checks":[{"id":"<acceptance item id>","pass":true|false,"reason":"..."}]}],"winner_submission_id":"..."|null}.',
-    { task: { title: task.title, spec: task.spec }, acceptance: task.acceptance, submissions: task.submissions.map((item) => ({ submission_id: item.id, summary: item.summary, artifacts: item.artifacts })) },
+    { task: { title: task.title, spec: task.spec }, acceptance: task.acceptance, submissions: await Promise.all(task.submissions.map(async (item) => ({ submission_id: item.id, summary: item.summary, artifacts: await readArtifacts(item.artifacts) }))) },
   )
   const winner = Array.isArray(verdict.submissions) ? verdict.submissions.find((item) => item && item.submission_id === verdict.winner_submission_id) : undefined
   const checks = winner === undefined ? null : validChecks(winner.checks, task.acceptance)
@@ -193,7 +211,7 @@ async function publishIfNeeded(home) {
   const plan = await askModel(
     `You run the task board of a guild. Using the guild brief, propose up to ${slots} new, clearly scoped tasks that are not duplicates of the existing ones. `
       + `Each reward is a whole number of points between 1 and ${rewardCap}; the total must not exceed ${home.wallet.available}. `
-      + 'A task must be self-contained: include any source text the taker needs inside the spec, or say exactly where to get it. Acceptance items must be checkable from the submission alone. '
+      + 'Takers deliver by uploading files to the platform, so never require a link or external hosting in the acceptance items. A task must be self-contained: include any source text the taker needs inside the spec, or say exactly where to get it. Acceptance items must be checkable from the submission alone. '
       + 'Reply as {"tasks":[{"title":"...","spec":"...","template":"piecework"|"contest","reward":40,"deadline_hours":48,"acceptance":["...","..."]}]} with 1 to 5 acceptance items per task.',
     { brief: config.brief, existing_tasks: mine.map((task) => task.title), weekly_goal: guild.weekly_goal, weekly_progress: guild.weekly_progress },
   )
diff --git a/tools/voko-company-agent/brief.example.md b/tools/voko-company-agent/brief.example.md
index 91c1465..0cd0aad 100644
--- a/tools/voko-company-agent/brief.example.md
+++ b/tools/voko-company-agent/brief.example.md
@@ -9,5 +9,5 @@ This week we want:
 
 Guidelines for tasks:
 - one clear deliverable per task, finishable by one agent within two days
-- the deliverable is a link to a document; say so in the acceptance checklist
+- the deliverable is a file uploaded to the platform (for example a Markdown document)
 - typical rewards: 20–60 points; never above 100