diff --git a/src/jira_hub/mirror.py b/src/jira_hub/mirror.py
new file mode 100644
index 0000000..cd97480
--- /dev/null
+++ b/src/jira_hub/mirror.py
@@ -0,0 +1,114 @@
+"""Зеркало задач Jira (issue, issue_link) и служебные заметки (issue_note).
+Зеркало пишет только загрузка состояния от агента; заметки обновление зеркала не трогает."""
+import json
+
+from . import db
+
+ISSUE_COLUMNS = ["key", "id", "issue_type", "summary", "description", "status", "priority", "assignee", "reporter",
+                 "duedate", "planned_start", "planned_end", "epic_key", "labels", "sprint", "created", "jira_updated"]
+NOTE_FIELDS = ["fact_status", "work_kind", "done_text", "rest_text", "owner_note"]
+
+_FILTERS = {"sprint": "i.sprint = ?", "assignee": "i.assignee = ?", "status": "i.status = ?", "epic": "i.epic_key = ?",
+            "work_kind": "n.work_kind = ?", "fact_status": "n.fact_status = ?"}
+
+
+def apply_state(conn, issues, links, neighbor_keys=(), fetched_at=None) -> dict:
+    """Upsert задач; связи с source_key среди присланных задач заменяются присланными.
+    Связи, у которых источник не прислан, не трогаются до загрузки их источника."""
+    fetched_at = fetched_at or db.now()
+    neighbors = set(neighbor_keys)
+    keys = []
+    with db.transaction(conn):
+        for it in issues:
+            row = {c: it.get(c) for c in ISSUE_COLUMNS}
+            row["labels"] = json.dumps(row.get("labels") or [], ensure_ascii=False)
+            row["fetched_at"] = fetched_at
+            row["neighbor"] = 1 if it["key"] in neighbors else 0
+            cols = list(row)
+            conn.execute(
+                f"INSERT INTO issue({', '.join(cols)}) VALUES ({', '.join('?' * len(cols))}) "
+                "ON CONFLICT(key) DO UPDATE SET " + ", ".join(f"{c} = excluded.{c}" for c in cols if c != "key"),
+                [row[c] for c in cols])
+            keys.append(it["key"])
+        conn.executemany("DELETE FROM issue_link WHERE source_key = ?", [(k,) for k in keys])
+        for link in links:
+            conn.execute("INSERT OR IGNORE INTO issue_link(source_key, target_key, link_type) VALUES (?, ?, ?)",
+                         (link["source_key"], link["target_key"], link["link_type"]))
+    return {"issues": len(keys), "links": len(links)}
+
+
+def known_keys(conn) -> list[str]:
+    return [r["key"] for r in conn.execute("SELECT key FROM issue ORDER BY key")]
+
+
+def _issue_dict(row) -> dict:
+    d = dict(row)
+    d["labels"] = json.loads(d.get("labels") or "[]")
+    d["neighbor"] = bool(d.get("neighbor"))
+    return d
+
+
+def list_issues(conn, filters=None, limit=50, offset=0) -> list[dict]:
+    filters = filters or {}
+    where, args = [], []
+    for name, sql in _FILTERS.items():
+        if filters.get(name) not in (None, ""):
+            where.append(sql)
+            args.append(filters[name])
+    if filters.get("label"):
+        where.append("EXISTS (SELECT 1 FROM json_each(i.labels) WHERE value = ?)")
+        args.append(filters["label"])
+    if filters.get("neighbor") not in (None, ""):
+        where.append("i.neighbor = ?")
+        args.append(1 if filters["neighbor"] in (True, 1, "1", "true") else 0)
+    if filters.get("q"):
+        where.append("(i.summary LIKE ? OR i.key LIKE ?)")
+        args += [f"%{filters['q']}%", f"%{filters['q']}%"]
+    sql = ("SELECT i.*, n.fact_status, n.work_kind FROM issue i LEFT JOIN issue_note n ON n.key = i.key"
+           + (" WHERE " + " AND ".join(where) if where else "")
+           + " ORDER BY i.duedate IS NULL, i.duedate, i.key LIMIT ? OFFSET ?")
+    return [_issue_dict(r) for r in conn.execute(sql, args + [int(limit), int(offset)])]
+
+
+def get_issue(conn, key) -> dict | None:
+    row = conn.execute("SELECT * FROM issue WHERE key = ?", (key,)).fetchone()
+    if row is None:
+        return None
+    d = _issue_dict(row)
+    d["links_out"] = [dict(r) for r in conn.execute(
+        "SELECT target_key, link_type FROM issue_link WHERE source_key = ? ORDER BY link_type, target_key", (key,))]
+    d["links_in"] = [dict(r) for r in conn.execute(
+        "SELECT source_key, link_type FROM issue_link WHERE target_key = ? ORDER BY link_type, source_key", (key,))]
+    d["note"] = get_note(conn, key)
+    d["commands"] = [dict(r) for r in conn.execute(
+        "SELECT id, batch_id, type, status, finished_at, error FROM command WHERE params LIKE ? ORDER BY id DESC LIMIT 10",
+        (f'%"{key}"%',))]
+    return d
+
+
+def get_note(conn, key) -> dict | None:
+    row = conn.execute("SELECT * FROM issue_note WHERE key = ?", (key,)).fetchone()
+    return dict(row) if row else None
+
+
+def set_note(conn, key, fields: dict, updated_by: str) -> dict:
+    unknown = set(fields) - set(NOTE_FIELDS)
+    if unknown:
+        raise ValueError(f"неизвестные поля заметки: {', '.join(sorted(unknown))}")
+    cur = get_note(conn, key) or {"key": key}
+    cur.update(fields)
+    cur["updated_at"], cur["updated_by"] = db.now(), updated_by
+    cols = ["key"] + NOTE_FIELDS + ["updated_at", "updated_by"]
+    conn.execute(f"INSERT INTO issue_note({', '.join(cols)}) VALUES ({', '.join('?' * len(cols))}) "
+                 "ON CONFLICT(key) DO UPDATE SET " + ", ".join(f"{c} = excluded.{c}" for c in cols[1:]),
+                 [cur.get(c) for c in cols])
+    return get_note(conn, key)
+
+
+def rename_note(conn, old_key, new_key) -> None:
+    """После создания задачи: заметка с временного ключа переезжает на настоящий (старая запись под новым ключом,
+    если вдруг была, уступает место)."""
+    if get_note(conn, old_key) is None:
+        return
+    conn.execute("DELETE FROM issue_note WHERE key = ?", (new_key,))
+    conn.execute("UPDATE issue_note SET key = ? WHERE key = ?", (new_key, old_key))
diff --git a/tests/test_mirror.py b/tests/test_mirror.py
new file mode 100644
index 0000000..d281b5c
--- /dev/null
+++ b/tests/test_mirror.py
@@ -0,0 +1,71 @@
+import pytest
+
+from jira_hub import db, mirror
+
+
+def issue(key, **over):
+    base = {"key": key, "id": "1", "issue_type": "Задача", "summary": f"Тема {key}", "description": "h3. Контекст",
+            "status": "Ожидание разработки", "priority": "Средний", "assignee": None, "reporter": "me",
+            "duedate": "2026-10-23", "planned_start": None, "planned_end": "2026-10-23", "epic_key": "AURORA-1350",
+            "labels": ["AWPCA"], "sprint": "Спринт 2", "created": "2026-10-10T12:00:00.000+0300",
+            "jira_updated": "2026-10-11T12:00:00.000+0300"}
+    base.update(over)
+    return base
+
+
+def test_apply_state_upserts_and_replaces_links():
+    conn = db.connect(":memory:")
+    links = [{"source_key": "A-1", "target_key": "A-2", "link_type": "ASUPR_Блокер_Начала"}]
+    out = mirror.apply_state(conn, [issue("A-1"), issue("A-2")], links)
+    assert out == {"issues": 2, "links": 1}
+    mirror.apply_state(conn, [issue("A-1", summary="Новая тема")],
+                       [{"source_key": "A-1", "target_key": "A-2", "link_type": "ASUPR_Связанные"}])
+    got = mirror.get_issue(conn, "A-1")
+    assert got["summary"] == "Новая тема" and got["labels"] == ["AWPCA"]
+    assert got["links_out"] == [{"target_key": "A-2", "link_type": "ASUPR_Связанные"}]
+    assert mirror.get_issue(conn, "A-2")["links_in"] == [{"source_key": "A-1", "link_type": "ASUPR_Связанные"}]
+
+
+def test_links_from_other_source_survive():
+    conn = db.connect(":memory:")
+    mirror.apply_state(conn, [issue("A-1"), issue("A-2")],
+                       [{"source_key": "A-2", "target_key": "A-1", "link_type": "ASUPR_Связанные"}])
+    mirror.apply_state(conn, [issue("A-1")], [])   # пришла только A-1 без связей
+    assert mirror.get_issue(conn, "A-1")["links_in"] == [{"source_key": "A-2", "link_type": "ASUPR_Связанные"}]
+
+
+def test_apply_state_marks_neighbors():
+    conn = db.connect(":memory:")
+    mirror.apply_state(conn, [issue("A-1"), issue("B-9")], [], neighbor_keys={"B-9"})
+    assert mirror.get_issue(conn, "B-9")["neighbor"] is True
+    assert mirror.get_issue(conn, "A-1")["neighbor"] is False
+    mirror.apply_state(conn, [issue("B-9")], [])   # вошла в базовую JQL
+    assert mirror.get_issue(conn, "B-9")["neighbor"] is False
+    assert mirror.known_keys(conn) == ["A-1", "B-9"]
+
+
+def test_note_survives_refresh_and_renames():
+    conn = db.connect(":memory:")
+    mirror.set_note(conn, "new:7", {"fact_status": "В работе", "work_kind": "разработка"}, "import")
+    mirror.rename_note(conn, "new:7", "A-5")
+    mirror.apply_state(conn, [issue("A-5")], [])
+    got = mirror.get_issue(conn, "A-5")
+    assert got["note"]["fact_status"] == "В работе" and got["note"]["updated_by"] == "import"
+    assert mirror.get_note(conn, "new:7") is None
+    with pytest.raises(ValueError):
+        mirror.set_note(conn, "A-5", {"summary": "нельзя"}, "x")
+
+
+def test_list_issues_filters():
+    conn = db.connect(":memory:")
+    mirror.apply_state(conn, [issue("A-1", sprint="Спринт 2", assignee="ivanov", duedate="2026-10-20"),
+                              issue("A-2", sprint="Спринт 1", labels=["AWPCA", "fact-done"]),
+                              issue("A-3", sprint="Спринт 2", duedate=None)], [])
+    mirror.set_note(conn, "A-3", {"work_kind": "тестирование"}, "x")
+    keys = [i["key"] for i in mirror.list_issues(conn, {"sprint": "Спринт 2"})]
+    assert keys == ["A-1", "A-3"]                       # без срока — последней
+    assert [i["key"] for i in mirror.list_issues(conn, {"label": "fact-done"})] == ["A-2"]
+    assert [i["key"] for i in mirror.list_issues(conn, {"work_kind": "тестирование"})] == ["A-3"]
+    assert [i["key"] for i in mirror.list_issues(conn, {"q": "A-2"})] == ["A-2"]
+    assert mirror.list_issues(conn, {"assignee": "ivanov"})[0]["work_kind"] is None
+    assert len(mirror.list_issues(conn, None, limit=1)) == 1