diff --git a/src/executor/checks.ts b/src/executor/checks.ts
new file mode 100644
index 0000000..d565aa7
--- /dev/null
+++ b/src/executor/checks.ts
@@ -0,0 +1,137 @@
+import { execFile } from 'node:child_process';
+import { mkdirSync, appendFileSync, writeFileSync } from 'node:fs';
+import { join } from 'node:path';
+import type { Project } from '../model/types.js';
+import { transcriptDir } from './runner.js';
+import { git } from './worktree.js';
+
+// ───────────────────────── 分项检查闸（lint / typecheck / build）─────────────────────────
+
+/** project.checks 解析后的命令表（缺省项跳过）。 */
+export interface ChecksConfig {
+  lint?: string;
+  typecheck?: string;
+  build?: string;
+}
+
+export interface ChecksResult {
+  ok: boolean;
+  failed: string | null;   // 第一个失败的检查项名（lint/typecheck/build）；全过=null
+  logRef: string | null;   // <transcriptDir>/<runId>.checks.log；无 checks 时 null
+  error?: string;
+}
+
+/** 校验函数签名（pipeline 依赖注入点，测试可 mock）。 */
+export type ChecksFn = (project: Project, dir: string, runId: string) => Promise<ChecksResult>;
+
+const CHECK_TIMEOUT_MS = 10 * 60_000; // 单项 10min
+
+/** 解析 project.checks（JSON 文本）；非法/空 → 空配置。只取 lint/typecheck/build 三项字符串。 */
+export function parseChecks(raw: string | null | undefined): ChecksConfig {
+  if (!raw?.trim()) return {};
+  try {
+    const obj = JSON.parse(raw) as Record<string, unknown>;
+    const out: ChecksConfig = {};
+    for (const k of ['lint', 'typecheck', 'build'] as const) {
+      const v = obj[k];
+      if (typeof v === 'string' && v.trim()) out[k] = v.trim();
+    }
+    return out;
+  } catch { return {}; }
+}
+
+function runOne(cmd: string, dir: string): Promise<{ ok: boolean; exit: number; stdout: string; stderr: string; timedOut: boolean }> {
+  return new Promise((resolve) => {
+    execFile('/bin/sh', ['-c', cmd], { cwd: dir, timeout: CHECK_TIMEOUT_MS, maxBuffer: 16 * 1024 * 1024 }, (err, stdout, stderr) => {
+      const rawCode = err ? (err as { code?: unknown }).code : 0;
+      const exit = typeof rawCode === 'number' ? rawCode : (err ? 1 : 0);
+      resolve({ ok: !err, exit, stdout, stderr, timedOut: (err as { killed?: boolean } | null)?.killed === true });
+    });
+  });
+}
+
+/**
+ * 分项静态检查闸：按 lint → typecheck → build 顺序在 worktree 内逐项跑，任一非 0 = 硬失败（报哪项挂）。
+ * 独立于 verifyCmd（verify 可跑测试，checks 跑静态门禁）。无 checks 配置 → 视为通过。
+ */
+export async function runChecks(project: Project, dir: string, runId: string): Promise<ChecksResult> {
+  const cfg = parseChecks(project.checks);
+  const items = (['lint', 'typecheck', 'build'] as const).filter((k) => cfg[k]);
+  if (items.length === 0) return { ok: true, failed: null, logRef: null };
+
+  const logDir = transcriptDir();
+  mkdirSync(logDir, { recursive: true });
+  const logRef = join(logDir, `${runId}.checks.log`);
+  writeFileSync(logRef, `# 分项检查（lint/typecheck/build）\n`);
+
+  for (const name of items) {
+    const cmd = cfg[name]!;
+    const r = await runOne(cmd, dir);
+    appendFileSync(logRef, `\n## ${name}: $ ${cmd}\n--- stdout ---\n${r.stdout}\n--- stderr ---\n${r.stderr}\n--- exit: ${r.exit} ---\n`);
+    if (!r.ok) {
+      const error = r.timedOut
+        ? `${name} 检查超时（>${CHECK_TIMEOUT_MS / 1000}s）：${cmd}`
+        : `${name} 检查失败（exit ${r.exit}）：${cmd}`;
+      return { ok: false, failed: name, logRef, error };
+    }
+  }
+  return { ok: true, failed: null, logRef };
+}
+
+// ───────────────────────── diff 体量闸 ─────────────────────────
+
+export interface DiffGateResult {
+  ok: boolean;
+  files: number;
+  lines: number;          // 增 + 删 总行数
+  error?: string;
+}
+
+/** 体量阈值：env 覆盖，0=不限。默认值放得较宽，仅拦截"明显过大/应先拆解"的改动。 */
+function diffLimits(): { maxFiles: number; maxLines: number } {
+  const num = (v: string | undefined, dflt: number): number => {
+    const n = Number(v);
+    return Number.isFinite(n) && n >= 0 ? n : dflt;
+  };
+  return {
+    maxFiles: num(process.env.MAESTRO_DIFF_MAX_FILES, 60),
+    maxLines: num(process.env.MAESTRO_DIFF_MAX_LINES, 3000),
+  };
+}
+
+/** diff 体量函数签名（pipeline 依赖注入点）。 */
+export type DiffGateFn = (repoPath: string, dir: string, branch: string, baseBranch: string) => Promise<DiffGateResult>;
+
+/**
+ * diff 体量闸：用 git diff --numstat 统计改动文件数 + 增删总行数，超阈值 = 硬失败
+ * （提示任务可能过大、应先拆解）。阈值由 env 配置，置 0 = 不限（关闸）。二进制文件行数计 0。
+ */
+export async function diffSizeGate(repoPath: string, _dir: string, branch: string, baseBranch: string): Promise<DiffGateResult> {
+  let out: string;
+  try {
+    out = (await git(repoPath, ['diff', '--numstat', `${baseBranch}...${branch}`])).trim();
+  } catch {
+    return { ok: true, files: 0, lines: 0 };   // 测不出体量（git 出错）→ 不拦截
+  }
+  let files = 0;
+  let lines = 0;
+  if (out) {
+    for (const row of out.split('\n')) {
+      const [add, del] = row.split('\t');
+      files++;
+      const a = Number(add); const d = Number(del);     // 二进制文件为 '-' → NaN → 计 0
+      lines += (Number.isFinite(a) ? a : 0) + (Number.isFinite(d) ? d : 0);
+    }
+  }
+  const { maxFiles, maxLines } = diffLimits();
+  const overFiles = maxFiles > 0 && files > maxFiles;
+  const overLines = maxLines > 0 && lines > maxLines;
+  if (overFiles || overLines) {
+    const parts = [
+      overFiles ? `文件数 ${files} > ${maxFiles}` : '',
+      overLines ? `改动行数 ${lines} > ${maxLines}` : '',
+    ].filter(Boolean).join('；');
+    return { ok: false, files, lines, error: `改动体量超阈值（${parts}）：任务可能过大，建议拆解后重做` };
+  }
+  return { ok: true, files, lines };
+}
diff --git a/src/executor/pipeline.ts b/src/executor/pipeline.ts
index 3acece0..2a12f9f 100644
--- a/src/executor/pipeline.ts
+++ b/src/executor/pipeline.ts
@@ -19,6 +19,7 @@ import { createWorktree, worktreeDiff, git, type WorktreeDiff, type WorktreeInfo
 import { runTask, runPlanner, runConflict, type RunnerFn, type PlannerFn } from './runner.js';
 import { runVerify, type VerifyFn } from './verify.js';
 import { reviewCode, reviewSecurity, type ReviewerFn } from './reviewer.js';
+import { runChecks, diffSizeGate, type ChecksFn, type DiffGateFn } from './checks.js';
 
 /** pipeline 的依赖注入面（便于单测 mock）；默认值取真实现。 */
 export interface PipelineDeps {
@@ -32,6 +33,10 @@ export interface PipelineDeps {
   runConflict: typeof runConflict; // 解冲突（conflict run）
   /** 执行前同步 defaultBranch：返回 null=成功，string=错误信息（已 abort）。可测试 mock。 */
   syncMain?: (dir: string, defaultBranch: string) => Promise<string | null>;
+  /** 分项检查闸（lint/typecheck/build），默认 checks.runChecks。 */
+  checks?: ChecksFn;
+  /** diff 体量闸，默认 checks.diffSizeGate。 */
+  diffGate?: DiffGateFn;
 }
 
 /** 执行前同步 defaultBranch 默认实现：fetch→merge origin/<branch>；失败再试本地 <branch>。 */
@@ -53,6 +58,18 @@ async function defaultSyncMain(dir: string, defaultBranch: string): Promise<stri
   }
 }
 
+/**
+ * approve 前硬门禁：分项检查闸（lint/typecheck/build）+ diff 体量闸。
+ * 返回 null=全过；string=失败原因（调用方据此 emit failed，不进复审）。
+ */
+async function runApproveGates(job: JobSpec, wt: WorktreeInfo, deps: PipelineDeps): Promise<string | null> {
+  const cr = await (deps.checks ?? runChecks)(job.project, wt.dir, job.runId);
+  if (!cr.ok) return cr.error ?? `分项检查失败：${cr.failed}`;
+  const dg = await (deps.diffGate ?? diffSizeGate)(job.project.repoPath, wt.dir, wt.branch, job.project.defaultBranch);
+  if (!dg.ok) return dg.error ?? 'diff 体量超阈值';
+  return null;
+}
+
 /** 真实依赖（worker 生产用）。 */
 export const realDeps: PipelineDeps = {
   createWorktree,
@@ -63,6 +80,8 @@ export const realDeps: PipelineDeps = {
   reviewSecurity,
   runPlanner,
   runConflict,
+  checks: runChecks,
+  diffGate: diffSizeGate,
 };
 
 /** emit：把一条 OutboxPayload 交给 outbox（worker 传 appendOutbox 包装，测试传收集器）。 */
@@ -149,6 +168,15 @@ export async function runPipeline(job: JobSpec, deps: PipelineDeps = realDeps, e
     return;
   }
 
+  // 3b. 分项检查闸（lint/typecheck/build）+ diff 体量闸——approve 前的硬门禁
+  emit({ type: 'phase', phase: 'checking' });
+  const gateErr = await runApproveGates(job, wt, deps);
+  if (gateErr !== null) {
+    emit({ type: 'failed', error: gateErr, transcriptRef: rr.transcriptRef, sessionId: rr.sessionId });
+    emit({ type: 'done' });
+    return;
+  }
+
   // 4. diff
   const diff = await deps.worktreeDiff(job.project.repoPath, wt.dir, wt.branch, job.project.defaultBranch);
 
@@ -254,6 +282,16 @@ async function runConflictPipeline(job: JobSpec, deps: PipelineDeps, emit: Emit)
     return;
   }
 
+  // 4b. 分项检查闸（解冲突后代码须仍通过 lint/typecheck/build）。
+  // 不走 diff 体量闸：解冲突的 diff 含整条原分支改动，体量天然大，闸会误伤。
+  emit({ type: 'phase', phase: 'checking' });
+  const cr = await (deps.checks ?? runChecks)(job.project, wt.dir, job.runId);
+  if (!cr.ok) {
+    emit({ type: 'failed', error: cr.error ?? `分项检查失败：${cr.failed}`, transcriptRef: rr.transcriptRef, sessionId: rr.sessionId });
+    emit({ type: 'done' });
+    return;
+  }
+
   // 5. diff
   const diff = await deps.worktreeDiff(job.project.repoPath, wt.dir, wt.branch, job.project.defaultBranch);
 
diff --git a/test/checks.test.ts b/test/checks.test.ts
new file mode 100644
index 0000000..54285c3
--- /dev/null
+++ b/test/checks.test.ts
@@ -0,0 +1,96 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { execFileSync } from 'node:child_process';
+import { parseChecks, runChecks, diffSizeGate } from '../src/executor/checks.js';
+import type { Project } from '../src/model/types.js';
+
+function withTmpData(cb: (dir: string) => Promise<void> | void): Promise<void> | void {
+  const dir = mkdtempSync(join(tmpdir(), 'maestro-checks-'));
+  const prev = process.env.MAESTRO_DATA_DIR;
+  process.env.MAESTRO_DATA_DIR = dir;
+  const done = () => {
+    if (prev === undefined) delete process.env.MAESTRO_DATA_DIR;
+    else process.env.MAESTRO_DATA_DIR = prev;
+    rmSync(dir, { recursive: true, force: true });
+  };
+  try {
+    const r = cb(dir);
+    if (r instanceof Promise) return r.finally(done);
+    done();
+  } catch (e) { done(); throw e; }
+}
+
+function proj(checks: string | null): Project {
+  return { checks, repoPath: '/tmp/x', defaultBranch: 'main' } as Project;
+}
+
+test('parseChecks：合法 JSON 取 lint/typecheck/build，非法/空 → {}', () => {
+  assert.deepEqual(parseChecks('{"lint":"npm run lint","build":"npm run build"}'), { lint: 'npm run lint', build: 'npm run build' });
+  assert.deepEqual(parseChecks('{"other":"x","typecheck":"  tsc  "}'), { typecheck: 'tsc' });
+  assert.deepEqual(parseChecks(null), {});
+  assert.deepEqual(parseChecks('not json'), {});
+  assert.deepEqual(parseChecks('{"lint":""}'), {});  // 空命令跳过
+});
+
+test('runChecks：无 checks → 通过', async () => {
+  await withTmpData(async (dir) => {
+    const r = await runChecks(proj(null), dir, 'run_a');
+    assert.equal(r.ok, true);
+    assert.equal(r.logRef, null);
+  });
+});
+
+test('runChecks：各项 exit0 → 通过；任一非0 → 失败并报哪项挂', async () => {
+  await withTmpData(async (dir) => {
+    const pass = await runChecks(proj('{"lint":"true","typecheck":"true"}'), dir, 'run_b');
+    assert.equal(pass.ok, true);
+    assert.equal(pass.failed, null);
+
+    const fail = await runChecks(proj('{"lint":"true","typecheck":"false","build":"true"}'), dir, 'run_c');
+    assert.equal(fail.ok, false);
+    assert.equal(fail.failed, 'typecheck');
+    assert.match(fail.error!, /typecheck 检查失败/);
+  });
+});
+
+test('diffSizeGate：超文件/行阈值 → 拦截；阈值内 → 通过', async () => {
+  const repo = mkdtempSync(join(tmpdir(), 'maestro-gitdiff-'));
+  const g = (args: string[]) => execFileSync('git', args, { cwd: repo }).toString();
+  g(['init', '-q', '-b', 'main']);
+  g(['config', 'user.email', 't@t']); g(['config', 'user.name', 't']);
+  writeFileSync(join(repo, 'base.txt'), 'base\n');
+  g(['add', '-A']); g(['commit', '-qm', 'base']);
+  g(['checkout', '-q', '-b', 'feature']);
+  // 改动：3 个文件、若干行
+  for (const f of ['a.txt', 'b.txt', 'c.txt']) writeFileSync(join(repo, f), 'x\ny\nz\n');
+  g(['add', '-A']); g(['commit', '-qm', 'feat']);
+
+  const prevF = process.env.MAESTRO_DIFF_MAX_FILES;
+  const prevL = process.env.MAESTRO_DIFF_MAX_LINES;
+  try {
+    process.env.MAESTRO_DIFF_MAX_FILES = '2';   // 3 文件 > 2 → 拦截
+    process.env.MAESTRO_DIFF_MAX_LINES = '0';
+    const over = await diffSizeGate(repo, repo, 'feature', 'main');
+    assert.equal(over.ok, false);
+    assert.equal(over.files, 3);
+    assert.match(over.error!, /文件数 3 > 2/);
+
+    process.env.MAESTRO_DIFF_MAX_FILES = '0';   // 0=不限
+    process.env.MAESTRO_DIFF_MAX_LINES = '0';
+    const under = await diffSizeGate(repo, repo, 'feature', 'main');
+    assert.equal(under.ok, true);
+    assert.equal(under.files, 3);
+  } finally {
+    if (prevF === undefined) delete process.env.MAESTRO_DIFF_MAX_FILES; else process.env.MAESTRO_DIFF_MAX_FILES = prevF;
+    if (prevL === undefined) delete process.env.MAESTRO_DIFF_MAX_LINES; else process.env.MAESTRO_DIFF_MAX_LINES = prevL;
+    rmSync(repo, { recursive: true, force: true });
+  }
+});
+
+test('diffSizeGate：git 出错 → 不拦截（测不出体量）', async () => {
+  const r = await diffSizeGate('/nonexistent-repo-xyz', '/tmp', 'a', 'b');
+  assert.equal(r.ok, true);
+});
diff --git a/test/pipeline.test.ts b/test/pipeline.test.ts
index 99ee067..7b68055 100644
--- a/test/pipeline.test.ts
+++ b/test/pipeline.test.ts
@@ -152,6 +152,35 @@ test('verify 失败：runner ok 但 verify !ok → emit failed（沿用 executor
   assert.equal(emitted.at(-1)?.type, 'done', '末尾应为 done');
 });
 
+test('checks 闸失败：verify 过但分项检查 !ok → emit failed（报哪项挂）+ done，无 result，不复审', async () => {
+  const { emitted, emit } = collector();
+  let reviewed = false;
+  await runPipeline(fakeJob, mockDeps({
+    checks: async () => ({ ok: false, failed: 'typecheck', logRef: '/tmp/c.log', error: 'typecheck 检查失败（exit 1）：tsc' }),
+    reviewCode: async () => { reviewed = true; return okReview; },
+  }), emit);
+
+  assert.equal(find(emitted, 'result'), undefined, 'checks 失败不应 emit result');
+  assert.equal(reviewed, false, 'checks 失败不应进入复审');
+  const failed = find(emitted, 'failed');
+  assert.ok(failed, '应 emit failed');
+  assert.match(failed.error!, /typecheck 检查失败/);
+  assert.equal(emitted.at(-1)?.type, 'done', '末尾应为 done');
+});
+
+test('diff 体量闸失败：emit failed（体量超阈值）+ done，无 result', async () => {
+  const { emitted, emit } = collector();
+  await runPipeline(fakeJob, mockDeps({
+    diffGate: async () => ({ ok: false, files: 99, lines: 9999, error: '改动体量超阈值（文件数 99 > 60）：任务可能过大，建议拆解后重做' }),
+  }), emit);
+
+  assert.equal(find(emitted, 'result'), undefined, 'diff 闸失败不应 emit result');
+  const failed = find(emitted, 'failed');
+  assert.ok(failed, '应 emit failed');
+  assert.match(failed.error!, /体量超阈值/);
+  assert.equal(emitted.at(-1)?.type, 'done', '末尾应为 done');
+});
+
 test('复审抛错不挡：reviewCode 抛错 → result 仍 emit，code.verdict=null 且 summary 含「自动复审失败」', async () => {
   const { emitted, emit } = collector();
   await runPipeline(fakeJob, mockDeps({