diff --git a/src/api/mail_routes.py b/src/api/mail_routes.py
new file mode 100644
index 0000000..7d42a29
--- /dev/null
+++ b/src/api/mail_routes.py
@@ -0,0 +1,230 @@
+"""API 路由 — Mail Tab（v2.7）
+
+Mail 是一个特殊的 Project (_mail)，每封 Mail 是一个两点 Task（from → to）。
+显示为独立 Tab，list 形式展示：时间 | From | To | Title | 状态（已读/已执行）。
+"""
+
+from __future__ import annotations
+
+import json
+from datetime import datetime
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+from fastapi import APIRouter, HTTPException, Query
+
+from src.blackboard.db import init_db
+from src.blackboard.models import Task
+from src.blackboard.operations import Blackboard
+from src.blackboard.queries import Queries
+from src.utils import get_data_root
+
+router = APIRouter(prefix="/api/mail", tags=["mail"])
+
+MAIL_PROJECT_ID = "_mail"
+
+
+def _db_path() -> Path:
+    root = get_data_root()
+    db = root / MAIL_PROJECT_ID / "blackboard.db"
+    db.parent.mkdir(parents=True, exist_ok=True)
+    init_db(db)
+    return db
+
+
+def _bb() -> Blackboard:
+    return Blackboard(_db_path())
+
+
+def _q() -> Queries:
+    return Queries(_db_path())
+
+
+def _mail_meta(task: Task) -> Dict[str, Any]:
+    """从 Task 的 must_haves 字段解析 Mail 元数据"""
+    if task.must_haves:
+        try:
+            return json.loads(task.must_haves)
+        except (json.JSONDecodeError, TypeError):
+            pass
+    return {}
+
+
+def _task_to_mail(task: Task) -> Dict[str, Any]:
+    """Task → Mail JSON"""
+    meta = _mail_meta(task)
+    return {
+        "id": task.id,
+        "title": task.title,
+        "from": meta.get("from", task.assigned_by),
+        "to": task.assignee,
+        "status": task.status,
+        "type": meta.get("type", "inform"),
+        "performative": meta.get("performative", "inform"),
+        "is_read": meta.get("is_read", False),
+        "created_at": task.created_at,
+        "updated_at": task.updated_at,
+        "description": task.description,
+        "conversation_id": meta.get("conversation_id"),
+        "in_reply_to": meta.get("in_reply_to"),
+    }
+
+
+@router.get("")
+async def list_mail(
+    status: Optional[str] = None,
+    from_agent: Optional[str] = None,
+    to_agent: Optional[str] = None,
+    unread: Optional[bool] = None,
+    limit: int = Query(50, le=200),
+):
+    """Mail 列表（按时间倒序）"""
+    bb = _bb()
+    tasks = bb.list_tasks(status=status, assignee=to_agent)
+
+    mails = []
+    for t in tasks:
+        meta = _mail_meta(t)
+        # from 过滤
+        if from_agent and meta.get("from", t.assigned_by) != from_agent:
+            continue
+        # unread 过滤
+        if unread is True and meta.get("is_read", False):
+            continue
+        mails.append(_task_to_mail(t))
+
+    # 按时间倒序
+    mails.sort(key=lambda m: m.get("created_at", ""), reverse=True)
+    mails = mails[:limit]
+
+    return {"mails": mails, "total": len(mails)}
+
+
+@router.get("/{mail_id}")
+async def get_mail(mail_id: str):
+    """Mail 详情"""
+    bb = _bb()
+    task = bb.get_task(mail_id)
+    if not task:
+        raise HTTPException(404, f"Mail not found: {mail_id}")
+
+    result = _task_to_mail(task)
+    # 附加 comments（用于对话线程）
+    comments = bb.get_comments(mail_id)
+    result["comments"] = [
+        {
+            "id": c.id,
+            "author": c.author,
+            "type": c.comment_type,
+            "body": c.body,
+            "created_at": c.created_at,
+        }
+        for c in comments
+    ]
+    return result
+
+
+@router.post("")
+async def send_mail(body: Dict[str, Any]):
+    """发送 Mail（创建 Task）"""
+    bb = _bb()
+
+    mail_id = body.get("id", f"mail-{int(datetime.now().timestamp() * 1000)}")
+    meta = {
+        "from": body.get("from", "user"),
+        "type": body.get("type", "text"),
+        "performative": body.get("performative", "inform"),
+        "is_read": False,
+        "conversation_id": body.get("conversation_id"),
+        "in_reply_to": body.get("in_reply_to"),
+    }
+
+    task = Task(
+        id=mail_id,
+        title=body.get("title", ""),
+        description=body.get("text", body.get("description", "")),
+        assignee=body.get("to"),
+        assigned_by=body.get("from", "user"),
+        must_haves=json.dumps(meta),
+        task_type="mail",
+        status="done" if body.get("type") == "inform" else "pending",
+    )
+    bb.create_task(task)
+    return {"ok": True, "mail_id": task.id}
+
+
+@router.patch("/{mail_id}")
+async def update_mail(mail_id: str, body: Dict[str, Any]):
+    """更新 Mail（标记已读/已执行）"""
+    bb = _bb()
+    task = bb.get_task(mail_id)
+    if not task:
+        raise HTTPException(404, f"Mail not found: {mail_id}")
+
+    meta = _mail_meta(task)
+
+    if "is_read" in body:
+        meta["is_read"] = body["is_read"]
+
+    if body.get("mark_executed"):
+        meta["is_read"] = True
+        if task.status not in ("done", "cancelled"):
+            bb.update_task_status(mail_id, "done", agent="mail-api")
+
+    # 写回 must_haves
+    conn = bb._conn()
+    try:
+        conn.execute("BEGIN IMMEDIATE")
+        conn.execute(
+            "UPDATE tasks SET must_haves=?, updated_at=datetime('now') WHERE id=?",
+            (json.dumps(meta), mail_id),
+        )
+        conn.commit()
+    finally:
+        conn.close()
+
+    return {"ok": True}
+
+
+@router.get("/agents/list")
+async def list_mail_agents():
+    """列出参与过 Mail 的所有 Agent（用于筛选）"""
+    q = _q()
+    conn = q._conn()
+    try:
+        # 从 assigned_by 和 assignee 去重
+        senders = conn.execute(
+            "SELECT DISTINCT assigned_by FROM tasks WHERE assigned_by IS NOT NULL"
+        ).fetchall()
+        receivers = conn.execute(
+            "SELECT DISTINCT assignee FROM tasks WHERE assignee IS NOT NULL"
+        ).fetchall()
+        agents = list(set(
+            [r["assigned_by"] for r in senders] +
+            [r["assignee"] for r in receivers]
+        ))
+        agents.sort()
+        return {"agents": agents}
+    finally:
+        conn.close()
+
+
+@router.get("/summary")
+async def mail_summary():
+    """Mail 摘要（未读数、总数）"""
+    q = _q()
+    bb = _bb()
+    all_tasks = bb.list_tasks()
+
+    total = len(all_tasks)
+    unread = 0
+    by_type: Dict[str, int] = {}
+
+    for t in all_tasks:
+        meta = _mail_meta(t)
+        if not meta.get("is_read", False):
+            unread += 1
+        t = meta.get("type", "inform")
+        by_type[t] = by_type.get(t, 0) + 1
+
+    return {"total": total, "unread": unread, "by_type": by_type}