diff --git a/README.md b/README.md
index 40fde36..cc1c92a 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,8 @@
 | pipeline_artifacts | 步骤产物 |
 | pipeline_human_tasks | 人工任务 |
 | pipeline_step_types | 步骤类型注册 |
+| pipeline_session_settings | 会话设置（多 tab 项目上下文） |
+| pipeline_conversations | 平台会话消息（回放缓存；2026-09-10 归籍本模块——唯一写入方 agent_loop_v2._save_turn，此前是无 models 定义的孤儿表） |
 
 ## 安装
 
diff --git a/models/pipeline_conversations.json b/models/pipeline_conversations.json
new file mode 100644
index 0000000..8563fd4
--- /dev/null
+++ b/models/pipeline_conversations.json
@@ -0,0 +1,31 @@
+{
+    "summary": [
+        {
+            "name": "pipeline_conversations",
+            "title": "平台会话消息表（回放缓存）",
+            "primary": ["id"],
+            "catelog": "entity"
+        }
+    ],
+    "fields": [
+        {"name": "id", "title": "主键ID", "type": "str", "length": 32, "nullable": "no"},
+        {"name": "pipeline_id", "title": "产线ID（空串=通用会话，隔离键）", "type": "str", "length": 32, "default": ""},
+        {"name": "iteration_id", "title": "项目ID（历史语义名，存project_id）", "type": "str", "length": 32, "default": ""},
+        {"name": "task_id", "title": "Pipeline任务ID（预留，当前零写入）", "type": "str", "length": 32, "default": ""},
+        {"name": "step_name", "title": "关联步骤名（预留，当前零写入）", "type": "str", "length": 100, "default": ""},
+        {"name": "role", "title": "消息角色", "type": "str", "length": 20, "nullable": "no", "default": "user"},
+        {"name": "content", "title": "消息正文（回放缓存，4000字截断）", "type": "text"},
+        {"name": "attachments", "title": "附件列表JSON（预留，当前零写入）", "type": "text"},
+        {"name": "msg_type", "title": "消息类型", "type": "str", "length": 20, "default": "text"},
+        {"name": "org_id", "title": "组织ID（预留，当前零写入）", "type": "str", "length": 32, "default": "0"},
+        {"name": "created_by", "title": "创建人用户ID", "type": "str", "length": 32, "default": ""},
+        {"name": "created_at", "title": "创建时间", "type": "timestamp", "nullable": "no"},
+        {"name": "session_id", "title": "会话ID（多tab隔离键，m0003补列）", "type": "str", "length": 32, "default": ""}
+    ],
+    "indexes": [
+        {"name": "idx_conv_created_by", "idxtype": "index", "idxfields": ["created_by"]},
+        {"name": "idx_conv_session", "idxtype": "index", "idxfields": ["session_id"]},
+        {"name": "idx_conv_iteration", "idxtype": "index", "idxfields": ["iteration_id"]},
+        {"name": "idx_conv_created", "idxtype": "index", "idxfields": ["created_at"]}
+    ]
+}