diff --git a/agent_go/executor.py b/agent_go/executor.py
index c9f2adf..8ceacd9 100644
--- a/agent_go/executor.py
+++ b/agent_go/executor.py
@@ -12,17 +12,13 @@
 
 __all__ = ["run_subtask"]
 
-def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=None, headless=False, issue_ref="", active_pids=None, active_pids_lock=None):
-    sub_id = subtask["id"]
+
+def _create_worktree(task_id, sub_id, repo, task_dir, logger):
+    """Create worktree for a subtask. Returns (worktree_path, create_time_ms)."""
     sub_dir = task_dir / sub_id
     sub_dir.mkdir(parents=True, exist_ok=True)
     worktree = sub_dir / "work"
 
-    logger.info(f"─── {sub_id} START: {subtask['title']} ───")
-    log_event(logger, "subtask_start", {"id": sub_id, "title": subtask["title"],
-                "depends_on": subtask.get("depends_on", []), "headless": headless, "issue": issue_ref})
-
-    clone_start = time.time()
     worktree_create_ms = 0
     if (worktree / ".git").exists():
         logger.info(f"worktree 已存在，跳过创建")
@@ -44,30 +40,11 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
         worktree.mkdir(parents=True, exist_ok=True)
         shutil.copytree(str(repo), str(worktree), dirs_exist_ok=True)
 
-    # 产物传递：通过 git merge 将上游代码合并到当前 worktree
-    # Tag 使用完整路径 task_id/sub_id 避免跨任务冲突
-    merge_conflicts = {}
-    merge_results = []
-    merge_upstream_ms = 0
-    if upstream_worktrees:
-        for up_id, up_path in upstream_worktrees.items():
-            if up_path.exists():
-                upstream_tag = f"{task_id}/{up_id}"
-                logger.info(f"产物传递 (git merge): {up_id} → {sub_id} (tag={upstream_tag})")
-                m_start = time.time()
-                _git_merge_upstream(up_path, worktree, upstream_tag, logger, headless=headless)
-                merge_upstream_ms += (time.time() - m_start) * 1000
-                # 检测上游 merge 是否产生冲突
-                conflict_file = worktree / ".MERGE_CONFLICT"
-                has_conflict = conflict_file.exists()
-                if has_conflict:
-                    merge_conflicts[up_id] = conflict_file.read_text(encoding="utf-8")
-                    conflict_file.unlink()
-                merge_results.append(collect_merge_result(up_id, not has_conflict,
-                    merge_conflicts.get(up_id, "").split("\n") if has_conflict else None))
-    clone_time = time.time() - clone_start
+    return worktree, worktree_create_ms
+
 
-    # 构建 TASK.md：包含完整 Agent Prompt、资源清单、上游上下文
+def _build_task_md(subtask, repo, task_dir, worktree, logger, headless, merge_conflicts=None):
+    """Build TASK.md content. Returns (task_md, verification, skill_names, unresolved_skills)."""
     task_md_parts = [f"# 子任务: {subtask['title']}", ""]
 
     # 注入 git merge 冲突信息（如有）
@@ -140,7 +117,6 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
                 logger.warning(f"Skill 未找到: \"{sn}\"，已跳过。已安装: {installed_names[:10]}")
 
     # 将 Agent Prompt 中的源项目路径替换为 worktree 路径，确保隔离
-    # 边界字符包含: 空白、引号、括号、冒号(含全角)、路径分隔符、中文标点
     task_md_text = "\n".join(task_md_parts)
     _boundary_chars = r'\s"\'\(\):/：，。、'
     _before = rf'(?<![^{_boundary_chars}])'
@@ -150,36 +126,12 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
         str(worktree),
         task_md_text
     )
-    (sub_dir / "TASK.md").write_text(task_md, encoding="utf-8")
 
-    # 重写验证命令中的路径
-    verification = subtask.get("verification", "")
-    if verification and str(repo) in verification:
-        _boundary_chars = r'\s"\'\(\):/：，。、'
-        _before = rf'(?<![^{_boundary_chars}])'
-        _after = rf'(?![^{_boundary_chars}])'
-        verification = re.sub(
-            rf'{_before}{re.escape(str(repo))}{_after}',
-            str(worktree),
-            verification
-        )
-
-    print(f"\n🚀 {sub_id}: {subtask['title']}")
-    env = os.environ.copy()
-    loaded_skill_names = [sn for sn in skill_names if sn not in unresolved_skills]
-    env.update({"AGENT_GO_TASK_ID": task_id, "AGENT_GO_SUBTASK_ID": sub_id, "AGENT_GO_WORKTREE": str(worktree), "AGENT_GO_SKILLS": ",".join(loaded_skill_names)})
+    return task_md, verification, skill_names, unresolved_skills
 
-    # ── Agent 类型配置 ──
-    agent_type_name = subtask.get("agent_type", "developer")
-    agent = load_agent_type(agent_type_name, repo)
-    if agent:
-        env.update(get_agent_env(agent))
-        logger.info(f"Agent: {agent.type_name}")
-    else:
-        from .agents import list_agent_types
-        available = [a["type"] for a in list_agent_types()]
-        logger.warning(f"Agent 类型 \"{agent_type_name}\" 未注册，降级为 developer。可用: {available}")
 
+def _run_claude(task_md, worktree, env, headless, agent, sub_id, active_pids, active_pids_lock, logger):
+    """Run Claude in headless or interactive mode. Returns (result, sandbox_type, claude_time)."""
     claude_start = time.time()
 
     if headless:
@@ -208,6 +160,12 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
 
     claude_time = time.time() - claude_start
 
+    return result, sandbox_type, claude_time
+
+
+def _verify_changes(task_id, subtask, worktree, headless, task_md, env, tag_name,
+                    active_pids, active_pids_lock, logger, issue_ref=""):
+    """Verify changes, commit if needed, run verification commands. Returns verification dict."""
     # 记录变更摘要（使用 git status --porcelain 检测所有变更，包括新文件）
     status_result = subprocess.run(["git", "status", "--porcelain"], cwd=str(worktree), capture_output=True, text=True)
     has_changes = bool(status_result.stdout.strip())
@@ -234,10 +192,9 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
 
     # Git 提交 + tag（Conventional Commits 格式），供下游子任务 merge
     # Tag 包含 task_id 前缀，避免跨任务冲突
-    tag_name = f"{task_id}/{sub_id}"
     git_start = time.time()
     if has_changes:
-        commit_msg = _format_commit(subtask['title'], issue_ref, sub_id)
+        commit_msg = _format_commit(subtask['title'], issue_ref, subtask["id"])
         add_result = subprocess.run(["git", "add", "-A"], cwd=str(worktree), capture_output=True)
         if add_result.returncode != 0:
             logger.warning(f"git add 失败: {add_result.stderr.strip()}")
@@ -302,10 +259,10 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
 f"错误输出:\n{vr.stderr[-500:]}\n"
 "请修复上述问题，确保所有验证命令通过。直接修改文件，不要询问。"
                     )
-                    _run_headless(fix_prompt, worktree, env, logger, f"{sub_id}-fix", active_pids=active_pids, active_pids_lock=active_pids_lock)
+                    _run_headless(fix_prompt, worktree, env, logger, f"{subtask['id']}-fix", active_pids=active_pids, active_pids_lock=active_pids_lock)
                     subprocess.run(["git", "add", "-A"], cwd=str(worktree), capture_output=True)
                     subprocess.run(["git", "commit", "-m",
-                                    f"{sub_id} (fix): 验证修复"], cwd=str(worktree),
+                                    f"{subtask['id']} (fix): 验证修复"], cwd=str(worktree),
                                    capture_output=True)
                     subprocess.run(["git", "tag", "-f", tag_name], cwd=str(worktree),
                                    capture_output=True)
@@ -345,7 +302,21 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
             else:
                 logger.info(f"验证 [{vi+1}/{len(cmds)}] 通过")
 
-    # 生成共享上下文（供下游子任务使用）
+    return {
+        "has_changes": has_changes,
+        "summary": summary,
+        "metrics_changes": metrics_changes,
+        "git_commit_ms": git_commit_ms,
+        "verification_ms": verification_ms,
+        "verification": verification,
+        "verify_ok": verify_ok,
+        "retry_count": retry_count,
+        "verification_results": verification_results,
+    }
+
+
+def _generate_context(subtask, task_dir, sub_id, logger, headless, result, verify_ok, summary, verification):
+    """Generate shared context file for downstream subtasks. Writes to context.md."""
     ctx_parts = [
         f"### {sub_id}: {subtask['title']}",
         f"- 状态: {'通过' if verify_ok else '需关注'}",
@@ -364,11 +335,109 @@ def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=Non
     ctx_parts.append("")
     # 线程安全地追加共享上下文
     # 写入独立上下文文件（仅被直接下游子任务读取）
-    ctx_file = sub_dir / "context.md"
+    ctx_file = task_dir / sub_id / "context.md"
     ctx_file.write_text("\n".join(ctx_parts) + "\n", encoding="utf-8")
     line_count = len("\n".join(ctx_parts).splitlines())
     logger.info(f"上下文已写入: {line_count} 行")
 
+
+def run_subtask(task_id, subtask, repo, task_dir, logger, upstream_worktrees=None, headless=False, issue_ref="", active_pids=None, active_pids_lock=None):
+    sub_id = subtask["id"]
+    sub_dir = task_dir / sub_id
+    sub_dir.mkdir(parents=True, exist_ok=True)
+
+    logger.info(f"─── {sub_id} START: {subtask['title']} ───")
+    log_event(logger, "subtask_start", {"id": sub_id, "title": subtask["title"],
+                "depends_on": subtask.get("depends_on", []), "headless": headless, "issue": issue_ref})
+
+    clone_start = time.time()
+
+    # 1. Create worktree
+    worktree, worktree_create_ms = _create_worktree(task_id, sub_id, repo, task_dir, logger)
+
+    # 2. Upstream merge (artifact passing)
+    merge_conflicts = {}
+    merge_results = []
+    merge_upstream_ms = 0
+    if upstream_worktrees:
+        for up_id, up_path in upstream_worktrees.items():
+            if up_path.exists():
+                upstream_tag = f"{task_id}/{up_id}"
+                logger.info(f"产物传递 (git merge): {up_id} → {sub_id} (tag={upstream_tag})")
+                m_start = time.time()
+                _git_merge_upstream(up_path, worktree, upstream_tag, logger, headless=headless)
+                merge_upstream_ms += (time.time() - m_start) * 1000
+                # 检测上游 merge 是否产生冲突
+                conflict_file = worktree / ".MERGE_CONFLICT"
+                has_conflict = conflict_file.exists()
+                if has_conflict:
+                    merge_conflicts[up_id] = conflict_file.read_text(encoding="utf-8")
+                    conflict_file.unlink()
+                merge_results.append(collect_merge_result(up_id, not has_conflict,
+                    merge_conflicts.get(up_id, "").split("\n") if has_conflict else None))
+    clone_time = time.time() - clone_start
+
+    # 3. Build TASK.md
+    task_md, verification, skill_names, unresolved_skills = _build_task_md(
+        subtask, repo, task_dir, worktree, logger, headless,
+        merge_conflicts=merge_conflicts
+    )
+
+    # Write TASK.md to disk
+    (sub_dir / "TASK.md").write_text(task_md, encoding="utf-8")
+
+    # Save original verification before path rewriting (for context.md)
+    original_verification = verification
+    # Rewrite verification command paths
+    if verification and str(repo) in verification:
+        _boundary_chars = r'\s"\'\(\):/：，。、'
+        _before = rf'(?<![^{_boundary_chars}])'
+        _after = rf'(?![^{_boundary_chars}])'
+        verification = re.sub(
+            rf'{_before}{re.escape(str(repo))}{_after}',
+            str(worktree),
+            verification
+        )
+
+    print(f"\n🚀 {sub_id}: {subtask['title']}")
+    env = os.environ.copy()
+    loaded_skill_names = [sn for sn in skill_names if sn not in unresolved_skills]
+    env.update({"AGENT_GO_TASK_ID": task_id, "AGENT_GO_SUBTASK_ID": sub_id, "AGENT_GO_WORKTREE": str(worktree), "AGENT_GO_SKILLS": ",".join(loaded_skill_names)})
+
+    # 4. Agent type configuration
+    agent_type_name = subtask.get("agent_type", "developer")
+    agent = load_agent_type(agent_type_name, repo)
+    if agent:
+        env.update(get_agent_env(agent))
+        logger.info(f"Agent: {agent.type_name}")
+    else:
+        from .agents import list_agent_types
+        available = [a["type"] for a in list_agent_types()]
+        logger.warning(f"Agent 类型 \"{agent_type_name}\" 未注册，降级为 developer。可用: {available}")
+
+    # 5. Run Claude
+    result, sandbox_type, claude_time = _run_claude(
+        task_md, worktree, env, headless, agent, sub_id, active_pids, active_pids_lock, logger
+    )
+
+    # 6. Verify changes
+    tag_name = f"{task_id}/{sub_id}"
+    verify_results = _verify_changes(
+        task_id, subtask, worktree, headless, task_md, env, tag_name,
+        active_pids, active_pids_lock, logger, issue_ref=issue_ref
+    )
+    has_changes = verify_results["has_changes"]
+    summary = verify_results["summary"]
+    metrics_changes = verify_results["metrics_changes"]
+    git_commit_ms = verify_results["git_commit_ms"]
+    verification_ms = verify_results["verification_ms"]
+    verify_ok = verify_results["verify_ok"]
+    retry_count = verify_results["retry_count"]
+    verification_results = verify_results["verification_results"]
+
+    # 7. Generate context (use original verification, not path-rewritten)
+    _generate_context(subtask, task_dir, sub_id, logger, headless, result, verify_ok, summary, original_verification)
+
     # 状态判定: completed(有变更) / no_changes(完成但无变更) / failed(异常)
     if result.returncode == 0 and verify_ok:
         status = "no_changes" if summary == "无文件变更" else "completed"