diff --git a/server/mcp_server_openviking_controlplane/README.md b/server/mcp_server_openviking_controlplane/README.md
index b3b44a9f..52ee49f5 100644
--- a/server/mcp_server_openviking_controlplane/README.md
+++ b/server/mcp_server_openviking_controlplane/README.md
@@ -4,7 +4,7 @@ MCP server **and** CLI for the OpenViking control plane (topapi) — manage OV
 libraries (`Collection`). Both front-ends share one core (`client.py`), so a tool
 added once is available from MCP and the CLI alike.
 
-Covers 11 collection lifecycle, billing, and user-management Actions:
+Covers 14 collection lifecycle, billing, user-management, and data-space Actions:
 
 | Action | MCP tool | CLI command |
 |---|---|---|
@@ -14,11 +14,14 @@ Covers 11 collection lifecycle, billing, and user-management Actions:
 | `UpdateOpenVikingCollection` | `update_collection` | `ov-cp update <rid>` |
 | `DeleteOpenVikingCollection` | `delete_collection` ⚠️ | `ov-cp delete <rid>` |
 | `GetOpenVikingUsage` | `get_usage` | `ov-cp usage <rid>` |
-| `AccessOpenVikingApiKey` (`/GetOpenVikingCollectionUserAccess`) | `get_collection_api_key` | `ov-cp api-key <rid>` |
-| `ListOpenVikingUser` (`/ListOpenVikingCollectionUser`) | `list_collection_users` | `ov-cp user list <rid>` |
-| `RegisterOpenVikingUser` | `register_collection_user` | `ov-cp user register <rid>` |
+| `GetOpenVikingCollectionUserAccess` | `get_collection_api_key` | `ov-cp api-key <rid>` |
+| `ListOpenVikingCollectionUser` | `list_collection_users` | `ov-cp user list <rid>` |
+| `RegisterOpenVikingUser` | `register_collection_user` | `ov-cp user register <rid> <uid>` |
 | `UpdateOpenVikingUser` | `update_collection_user` | `ov-cp user update <rid> <uid>` |
 | `DeleteOpenVikingUser` | `delete_collection_user` ⚠️ | `ov-cp user delete <rid> <uid>` |
+| `ListOpenVikingAccounts` | `list_collection_accounts` | `ov-cp account list <rid>` |
+| `CreateOpenVikingAccount` | `create_collection_account` | `ov-cp account create <rid> <account-id>` |
+| `DeleteOpenVikingAccount` | `delete_collection_account` ⚠️ | `ov-cp account delete <rid> <account-id>` |
 
 The `user *` actions manage the multiple users of an enterprise-tier library; they
 require the AgentPlan key to be **associated with the target library**. A user's
@@ -26,6 +29,18 @@ require the AgentPlan key to be **associated with the target library**. A user's
 data-plane key via `api-key <rid> --user-id <uid>`. Newly registered users always
 have role `user`; `user update` currently supports API Key rotation only.
 
+The `account *` actions manage enterprise-tier data spaces: first-level isolation
+boundaries for users, credentials, memories, resources, sessions, and skills. The
+released backend uses account `default` when `--account-id` is omitted, preserving
+existing behavior. Every account-aware action serializes the scope as
+`OpenVikingAccountID` on the wire. Creating one automatically adds its `default`
+admin user. An OpenVikingAccountID is 1-64 characters using only ASCII letters,
+digits, `_`, `.`, `@`, or `-`; it cannot start with `_`, equal `.` or `..`, or
+contain more than one `@`. The per-library quota is backend-configured (currently
+100 by default). Deleting a data space cascades to everything inside it and is
+irreversible; `default` cannot be deleted. Treat `CreateTime` from `account list`
+as an opaque backend timestamp string.
+
 ## Endpoint
 
 The control-plane TopAPI is compiled into the OpenViking **data-plane cluster**;
@@ -53,8 +68,8 @@ pluggable (`common/auth.py` → `BearerTokenAuth`); an AK/SK signer can be swapp
 later without touching the rest.
 
 > ⚠️ Write actions like `create` require the account to have **AgentPlan deduction
-> activated**, otherwise they return `ProductUnordered`. Read-only actions
-> (list/get/usage/delete) are not gated.
+> activated**, otherwise they return `ProductUnordered`. Operations on an existing
+> library can additionally require the AgentPlan key to be associated with that library.
 
 ### Configuration
 
@@ -67,7 +82,7 @@ later without touching the rest.
 
 `VIKING_EXTRA_HEADERS` is a comma-separated list of `Key: Value` pairs; `--header`
 takes one pair and may be repeated (CLI wins over env). Both are merged onto every
-request — useful for swim-lane routing, e.g. `-H 'x-tt-env: lujiakun'`. The
+request — useful for swim-lane routing, e.g. `-H 'x-tt-env: <swimlane>'`. The
 `Authorization` and `Content-Type` headers are protected and cannot be overridden.
 
 ## CLI usage
@@ -82,8 +97,13 @@ export AGENTPLAN_API_KEY=ark-xxxxxxxx
 uv run ov-cp list
 uv run ov-cp get   <ResourceID>
 uv run ov-cp usage <ResourceID>
+uv run ov-cp usage <ResourceID> --account-id team-alpha
+uv run ov-cp usage <ResourceID> --user-id alice  # user in default data space
+uv run ov-cp usage <ResourceID> --account-id team-alpha --user-id alice
 uv run ov-cp api-key <ResourceID>
-uv run ov-cp api-key <ResourceID> --user-id xiaohong
+uv run ov-cp api-key <ResourceID> --user-id alice
+uv run ov-cp api-key <ResourceID> --account-id team-alpha
+uv run ov-cp api-key <ResourceID> --account-id team-alpha --user-id alice
 
 # create (consumes paid quota; always uses the AgentPlan model path and the
 # configured AgentPlan key; model source/parameters and image version are hidden)
@@ -121,17 +141,22 @@ uv run ov-cp update <ResourceID> --model-api-key ark-xxxxxxxx
 
 # manage users of an enterprise-tier library (key must be associated with it)
 uv run ov-cp user list     <ResourceID>
-uv run ov-cp user list     <ResourceID> --role user --page 1 --limit 20
-uv run ov-cp user register <ResourceID> xiaohong
-uv run ov-cp user update   <ResourceID> xiaohong --regenerate-key
-uv run ov-cp user delete   <ResourceID> xiaohong --yes
+uv run ov-cp user list     <ResourceID> --account-id team-alpha --role user --page 1 --limit 20
+uv run ov-cp user register <ResourceID> alice --account-id team-alpha
+uv run ov-cp user update   <ResourceID> alice --account-id team-alpha --regenerate-key
+uv run ov-cp user delete   <ResourceID> alice --account-id team-alpha --yes
+
+# manage data spaces (accounts) in an enterprise-tier library
+uv run ov-cp account list   <ResourceID> --keyword team --page 1 --limit 20
+uv run ov-cp account create <ResourceID> team-alpha
+uv run ov-cp account delete <ResourceID> team-alpha  # prompts before cascading deletion
 
 # delete (irreversible)
 uv run ov-cp delete <ResourceID> --yes
 ```
 
 When stdout is a terminal, `--output auto` (the default) renders structured
-Rich views: tables for collection/user lists, sectioned detail panels for
+Rich views: tables for collection/user/data-space lists, sectioned detail panels for
 `get`/`usage`, compact success cards for mutations, and a warning panel for
 plaintext API keys. Piping or redirecting automatically keeps standard JSON:
 
@@ -143,10 +168,11 @@ uv run ov-cp --output json-compact list
 uv run ov-cp --output pretty list     # force the terminal view
 ```
 
-`usage` preserves the backend's legacy `EstimatedCosts` field and also returns
-`EstimatedBilling` with an explicit hourly period and CNY unit. For collections
-paid by AgentPlan it includes the equivalent AFP deduction and payment scenario;
-for `volc_pay` it reports CNY only.
+Library-wide `usage` preserves the backend's legacy `EstimatedCosts` field and also
+returns `EstimatedBilling` with an explicit hourly period and CNY unit. For
+collections paid by AgentPlan it includes the equivalent AFP deduction and payment
+scenario; for `volc_pay` it reports CNY only. Account- or user-scoped usage omits
+both library-wide estimates. `--user-id` may be used alone for the `default` account.
 
 Flags override env. The endpoint defaults to the public gateway; override it only
 for testing (e.g. against a port-forward) with `-e` / `VIKING_ENDPOINT` —
@@ -168,7 +194,7 @@ gateway. Add to `.mcp.json`:
       "command": "uvx",
       "args": [
         "--from",
-        "mcp-server-openviking-controlplane>=0.2.0",
+        "mcp-server-openviking-controlplane>=0.3.0",
         "mcp-server-openviking-controlplane"
       ],
       "env": {
@@ -267,6 +293,7 @@ A Claude Code / agent skill that documents the `ov-cp` workflow lives at
 Symlink or copy it into your agent's skills directory (e.g. `~/.claude/skills/`) to
 let an agent drive the control plane.
 
-> ⚠️ `create_collection` / `delete_collection` create/destroy **billable** resources and
-> are exposed as MCP tools; their descriptions instruct the model to confirm with you
-> first. Rely on your client's tool-permission prompt as the final gate.
+> ⚠️ `create_collection` / `delete_collection` create/destroy **billable** resources,
+> while `delete_collection_account` irreversibly destroys a data space and all of its
+> contents. These are exposed as MCP tools; their descriptions instruct the model to
+> confirm with you first. Rely on your client's tool-permission prompt as the final gate.
diff --git a/server/mcp_server_openviking_controlplane/README_zh.md b/server/mcp_server_openviking_controlplane/README_zh.md
index db78349a..38760fdf 100644
--- a/server/mcp_server_openviking_controlplane/README_zh.md
+++ b/server/mcp_server_openviking_controlplane/README_zh.md
@@ -4,7 +4,7 @@ OpenViking 控制面（topapi）的 MCP Server **与** CLI —— 用于管理 O
 （`Collection`）。两个前端共用同一套核心（`client.py`），新增一个能力即可同时被 MCP
 和 CLI 使用。
 
-覆盖 11 个库生命周期、计费与用户管理 Action：
+覆盖 14 个库生命周期、计费、用户管理与数据空间 Action：
 
 | Action | MCP tool | CLI 命令 |
 |---|---|---|
@@ -14,17 +14,29 @@ OpenViking 控制面（topapi）的 MCP Server **与** CLI —— 用于管理 O
 | `UpdateOpenVikingCollection` | `update_collection` | `ov-cp update <rid>` |
 | `DeleteOpenVikingCollection` | `delete_collection` ⚠️ | `ov-cp delete <rid>` |
 | `GetOpenVikingUsage` | `get_usage` | `ov-cp usage <rid>` |
-| `AccessOpenVikingApiKey`（路径 `/GetOpenVikingCollectionUserAccess`） | `get_collection_api_key` | `ov-cp api-key <rid>` |
-| `ListOpenVikingUser`（路径 `/ListOpenVikingCollectionUser`） | `list_collection_users` | `ov-cp user list <rid>` |
-| `RegisterOpenVikingUser` | `register_collection_user` | `ov-cp user register <rid>` |
+| `GetOpenVikingCollectionUserAccess` | `get_collection_api_key` | `ov-cp api-key <rid>` |
+| `ListOpenVikingCollectionUser` | `list_collection_users` | `ov-cp user list <rid>` |
+| `RegisterOpenVikingUser` | `register_collection_user` | `ov-cp user register <rid> <uid>` |
 | `UpdateOpenVikingUser` | `update_collection_user` | `ov-cp user update <rid> <uid>` |
 | `DeleteOpenVikingUser` | `delete_collection_user` ⚠️ | `ov-cp user delete <rid> <uid>` |
+| `ListOpenVikingAccounts` | `list_collection_accounts` | `ov-cp account list <rid>` |
+| `CreateOpenVikingAccount` | `create_collection_account` | `ov-cp account create <rid> <account-id>` |
+| `DeleteOpenVikingAccount` | `delete_collection_account` ⚠️ | `ov-cp account delete <rid> <account-id>` |
 
 `user *` 系列管理企业版库的多用户，要求 AgentPlan key **与目标库已关联**。`user list`
 返回的用户 `ApiKey` 是**掩码**，取指定用户的明文数据面 key 使用
 `api-key <rid> --user-id <uid>`。新注册用户的角色固定为 `user`；`user update`
 当前只支持重生 API Key。
 
+`account *` 系列管理企业版库的数据空间：它是用户、凭证、记忆、资源、会话与技能的
+一级隔离边界。已发布后端在省略 `--account-id` 时使用数据空间 `default`，因此存量用法
+保持不变。所有支持数据空间的接口都在请求体中以 `OpenVikingAccountID` 传递该范围。
+新建数据空间时会自动添加其 `default` 管理员用户。OpenVikingAccountID 长度为 1-64 个
+字符，只能包含 ASCII 字母、数字、`_`、`.`、`@`、`-`；不能以 `_` 开头，不能等于 `.`
+或 `..`，且至多包含一个 `@`。单库配额由后端配置（当前默认 100）。删除数据空间会不可逆
+地级联删除其中所有内容；`default` 不可删除。将 `account list` 返回的 `CreateTime` 视为
+后端不透明时间戳字符串。
+
 ## 端点
 
 控制面 TopAPI 接口已编译进 OpenViking **数据面集群**，每个 Action 由数据面网关在如下路径提供：
@@ -49,7 +61,7 @@ Action 在 **path** 里（不走 `?Action=&Version=` query）。请求体是该
 （`common/auth.py` → `BearerTokenAuth`），后续要换 AK/SK 签名时只需替换这一处。
 
 > ⚠️ `create` 等写接口要求账号已**开通 AgentPlan 抵扣**，否则返回 `ProductUnordered`；
-> 只读接口（list/get/usage/delete）不受此限。
+> 操作已有库时还可能要求 AgentPlan key 已与目标库关联。
 
 ### 配置
 
@@ -62,7 +74,7 @@ Action 在 **path** 里（不走 `?Action=&Version=` query）。请求体是该
 
 `VIKING_EXTRA_HEADERS` 是逗号分隔的 `Key: Value` 列表；`--header` 每次带一对、可重复
 （CLI 优先于环境变量）。两者合并后加到每个请求上，常用于泳道路由，例如
-`-H 'x-tt-env: lujiakun'`。`Authorization`、`Content-Type` 为受保护头，不可覆盖。
+`-H 'x-tt-env: <swimlane>'`。`Authorization`、`Content-Type` 为受保护头，不可覆盖。
 
 ## CLI 用法
 
@@ -76,8 +88,13 @@ export AGENTPLAN_API_KEY=ark-xxxxxxxx
 uv run ov-cp list
 uv run ov-cp get   <ResourceID>
 uv run ov-cp usage <ResourceID>
+uv run ov-cp usage <ResourceID> --account-id team-alpha
+uv run ov-cp usage <ResourceID> --user-id alice  # default 数据空间内的用户
+uv run ov-cp usage <ResourceID> --account-id team-alpha --user-id alice
 uv run ov-cp api-key <ResourceID>
-uv run ov-cp api-key <ResourceID> --user-id xiaohong
+uv run ov-cp api-key <ResourceID> --user-id alice
+uv run ov-cp api-key <ResourceID> --account-id team-alpha
+uv run ov-cp api-key <ResourceID> --account-id team-alpha --user-id alice
 
 # 建库（消耗付费配额；固定使用 AgentPlan 模型路径和已配置的 AgentPlan key，
 #       不开放模型来源、模型参数、模型鉴权与 OpenViking 镜像版本）
@@ -110,17 +127,22 @@ uv run ov-cp update <ResourceID> --model-api-key ark-xxxxxxxx
 
 # 管理企业版库的用户（key 需与该库已关联）
 uv run ov-cp user list     <ResourceID>
-uv run ov-cp user list     <ResourceID> --role user --page 1 --limit 20
-uv run ov-cp user register <ResourceID> xiaohong
-uv run ov-cp user update   <ResourceID> xiaohong --regenerate-key
-uv run ov-cp user delete   <ResourceID> xiaohong --yes
+uv run ov-cp user list     <ResourceID> --account-id team-alpha --role user --page 1 --limit 20
+uv run ov-cp user register <ResourceID> alice --account-id team-alpha
+uv run ov-cp user update   <ResourceID> alice --account-id team-alpha --regenerate-key
+uv run ov-cp user delete   <ResourceID> alice --account-id team-alpha --yes
+
+# 管理企业版库的数据空间（Account）
+uv run ov-cp account list   <ResourceID> --keyword team --page 1 --limit 20
+uv run ov-cp account create <ResourceID> team-alpha
+uv run ov-cp account delete <ResourceID> team-alpha  # 级联删除前会要求确认
 
 # 删库（不可逆）
 uv run ov-cp delete <ResourceID> --yes
 ```
 
 默认的 `--output auto` 在 stdout 连接终端时使用 Rich 结构化视图：
-库/用户列表显示为表格，`get`/`usage` 显示为分区详情卡片，写操作显示精简成功卡片，
+库/用户/数据空间列表显示为表格，`get`/`usage` 显示为分区详情卡片，写操作显示精简成功卡片，
 明文 API Key 则显示敏感信息警告。管道和重定向会自动保持标准 JSON：
 
 ```bash
@@ -131,9 +153,10 @@ uv run ov-cp --output json-compact list
 uv run ov-cp --output pretty list     # 强制终端视图
 ```
 
-`usage` 保留后端原有的 `EstimatedCosts` 字段，同时新增 `EstimatedBilling`，
+库级 `usage` 保留后端原有的 `EstimatedCosts` 字段，同时新增 `EstimatedBilling`，
 明确费用为每小时 CNY 估值。AgentPlan 支付的库还会返回对应的 AFP 抵扣量和
-支付场景；`volc_pay` 只返回 CNY。
+支付场景；`volc_pay` 只返回 CNY。按数据空间或用户查询时会去掉这两个库级估值。
+`--user-id` 可单独使用，此时查询 `default` 数据空间。
 
 命令行参数优先于环境变量。端点默认指向公网网关；仅在测试时（如指向 port-forward）才用
 `-e` / `VIKING_ENDPOINT` 覆盖：`uv run ov-cp -e http://localhost:18080 list`。
@@ -153,7 +176,7 @@ streamable HTTP 的方式挂在网关后面。`.mcp.json` 配置：
       "command": "uvx",
       "args": [
         "--from",
-        "mcp-server-openviking-controlplane>=0.2.0",
+        "mcp-server-openviking-controlplane>=0.3.0",
         "mcp-server-openviking-controlplane"
       ],
       "env": {
@@ -240,5 +263,6 @@ HTTP 传输下 AgentPlan ApiKey **按请求解析**，因此单个进程可以
 
 需要 SSE 时：`mcp-server-openviking-controlplane --transport sse`。
 
-> ⚠️ `create_collection` / `delete_collection` 会创建/销毁**付费**资源，且已暴露为 MCP
-> tool；其描述会要求模型先与你确认。最终拦截依赖客户端的工具授权弹窗。
+> ⚠️ `create_collection` / `delete_collection` 会创建/销毁**付费**资源；
+> `delete_collection_account` 会不可逆地销毁数据空间及其全部内容。这些能力均已暴露为
+> MCP tool，其描述会要求模型先与你确认。最终拦截依赖客户端的工具授权弹窗。
diff --git a/server/mcp_server_openviking_controlplane/pyproject.toml b/server/mcp_server_openviking_controlplane/pyproject.toml
index 5f909fcd..61d445df 100644
--- a/server/mcp_server_openviking_controlplane/pyproject.toml
+++ b/server/mcp_server_openviking_controlplane/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "mcp-server-openviking-controlplane"
-version = "0.2.0"
+version = "0.3.0"
 description = "MCP server and CLI for the OpenViking control plane (topapi) collection management"
 readme = "README.md"
 requires-python = ">=3.10"
diff --git a/server/mcp_server_openviking_controlplane/skills/openviking-controlplane/SKILL.md b/server/mcp_server_openviking_controlplane/skills/openviking-controlplane/SKILL.md
index fb47349d..c5cdcaef 100644
--- a/server/mcp_server_openviking_controlplane/skills/openviking-controlplane/SKILL.md
+++ b/server/mcp_server_openviking_controlplane/skills/openviking-controlplane/SKILL.md
@@ -1,6 +1,6 @@
 ---
 name: openviking-controlplane
-description: Manage OpenViking collections (OV libraries) from the command line with `ov-cp` — list / create / get / update / usage / get the data-plane API key / delete, plus managing the users of an enterprise-tier library (list / register / update / delete) and configuring how a library is billed (AgentPlan AFP deduction vs Volcano pay-as-you-go, `--pay-type` / `--seat-id`). Use when the user wants to provision or inspect an OpenViking library, fetch a library's data-plane API key, do the create→get-key cold-start, manage a library's users, set or switch a library's billing, or otherwise drive the OpenViking control plane (topapi). Authenticates with an Ark AgentPlan ApiKey.
+description: Manage OpenViking collections (OV libraries) from the command line with `ov-cp` — list / create / get / update / usage / get the data-plane API key / delete, plus managing the users and account data spaces of an enterprise-tier library (list / create / register / update / delete), account-scoped users / API keys / usage, and configuring how a library is billed (AgentPlan AFP deduction vs Volcano pay-as-you-go, `--pay-type` / `--seat-id`). Use when the user wants to provision or inspect an OpenViking library, fetch a library's data-plane API key, do the create→get-key cold-start, manage a library's users or accounts / 数据空间, set or switch a library's billing, or otherwise drive the OpenViking control plane (topapi). Authenticates with an Ark AgentPlan ApiKey.
 ---
 
 # OpenViking Control Plane (`ov-cp`)
@@ -38,8 +38,12 @@ export AGENTPLAN_API_KEY=ark-xxxxxxxx
 ov-cp list                       # list collections (optionally --project X)
 ov-cp get     <ResourceID>       # collection info (Status, models, version, ...)
 ov-cp usage   <ResourceID>       # file counts / hourly CNY and AgentPlan AFP estimate
+ov-cp usage   <ResourceID> --account-id team-alpha
+ov-cp usage   <ResourceID> --user-id alice  # user in account default
+ov-cp usage   <ResourceID> --account-id team-alpha --user-id alice
 ov-cp api-key <ResourceID>       # default user's plaintext data-plane key
-ov-cp api-key <ResourceID> --user-id xiaohong  # selected user's plaintext key
+ov-cp api-key <ResourceID> --user-id alice  # selected user's plaintext key
+ov-cp api-key <ResourceID> --account-id team-alpha --user-id alice
 ov-cp create  --name my_kb       # create a collection (see below)
 ov-cp update  <ResourceID> --description "..."   # update fields / switch billing
 ov-cp update  <ResourceID> --model-api-key ark-xxx  # overwrite AgentPlan model key
@@ -48,14 +52,26 @@ ov-cp delete  <ResourceID> --yes # delete (irreversible; uninstalls the Helm rel
 # users of an enterprise-tier library (key must be associated with the library):
 ov-cp user list     <ResourceID>                     # users (ApiKey is masked)
 ov-cp user list     <ResourceID> --role user --page 1 --limit 20
-ov-cp user register <ResourceID> xiaohong            # new users always get role=user
-ov-cp user update   <ResourceID> xiaohong --regenerate-key
-ov-cp user delete   <ResourceID> xiaohong --yes      # revoke a user's credential
+ov-cp user register <ResourceID> alice            # new users always get role=user
+ov-cp user update   <ResourceID> alice --regenerate-key
+ov-cp user delete   <ResourceID> alice --yes      # revoke a user's credential
+
+# target a non-default data space with --account-id:
+ov-cp user list     <ResourceID> --account-id team-alpha
+ov-cp user register <ResourceID> alice --account-id team-alpha
+ov-cp user update   <ResourceID> alice --account-id team-alpha --regenerate-key
+ov-cp user delete   <ResourceID> alice --account-id team-alpha --yes
+
+# data spaces (accounts) of an enterprise-tier library:
+ov-cp account list   <ResourceID> --keyword team --page 1 --limit 20
+ov-cp account create <ResourceID> team-alpha
+ov-cp account delete <ResourceID> team-alpha  # prompts before cascading deletion
 ```
 
 After `user update --regenerate-key`, fetch the replacement with
 `api-key <ResourceID> --user-id <UserID>`; the update response only confirms
-success and does not contain the new key.
+success and does not contain the new key. Include `--account-id <OpenVikingAccountID>` when
+the user is outside account `default`.
 
 `update --model-api-key <ark-key>` overwrites the library's AgentPlan MODEL
 credential; VLM and Embedding always share one key, and the library's other
@@ -77,9 +93,43 @@ substitution remain safe. Use the global `--json`, `--output json-compact`, or
 stderr with exit code 1. `ov-cp --help` and `ov-cp <cmd> --help` work without
 any config.
 
-`usage` keeps `EstimatedCosts` for compatibility and adds `EstimatedBilling`.
-That object identifies the hourly period and CNY estimate; AgentPlan-paid
-collections also include the AFP amount and business scenario.
+Library-wide `usage` keeps `EstimatedCosts` for compatibility and adds
+`EstimatedBilling`. That object identifies the hourly period and CNY estimate;
+AgentPlan-paid collections also include the AFP amount and business scenario.
+Account- or user-scoped usage omits both library-wide fields. `--user-id` may be
+used alone for a user in account `default`.
+
+## Data spaces (accounts)
+
+Treat an account as an enterprise-tier library's first-level isolation boundary
+for users, credentials, memories, resources, sessions, and skills. Treat
+`default` as the released backend's default account, so omitting
+`--account-id` preserves existing behavior. Every account-aware action sends the
+scope as `OpenVikingAccountID`. Expect a newly created data space to
+contain an automatically created `default` admin user.
+
+Validate OpenVikingAccountID locally before sending a request; reject invalid input without
+a backend request or cost. Apply all of these naming rules:
+
+- Require 1-64 characters.
+- Allow only ASCII letters, digits, `_`, `.`, `@`, and `-`; reject spaces and Chinese characters.
+- Reject an ID that starts with `_`.
+- Reject `.` and `..`.
+- Allow at most one `@`.
+
+Respect the backend-configured per-library account quota. Treat 100 as the current
+default, not as a fixed limit. Treat `CreateTime` from `account list` as an opaque
+backend timestamp string. Never delete account `default`.
+
+Use this confirmation workflow before deleting any other data space:
+
+1. First restate the target library ResourceID, exact OpenVikingAccountID, and full destruction scope: every user, credential, memory, resource, session, and skill in the data space. Ask the user to confirm that scope.
+2. After that confirmation, require the user to repeat the exact OpenVikingAccountID.
+3. Compare the repeated OpenVikingAccountID exactly with the target. Never infer an OpenVikingAccountID from a keyword or partial match in `account list`.
+4. Only after both confirmations, run `ov-cp account delete <ResourceID> <OpenVikingAccountID> --yes`.
+
+Never use `--yes` on the first deletion step. Stop if either confirmation is
+missing or the repeated OpenVikingAccountID does not match exactly.
 
 ## Creating a collection
 
@@ -145,14 +195,20 @@ The returned `ApiKey` is the library's **data-plane** key. Use it as
 ## Notes
 
 - Only `Authorization: Bearer` is accepted (no `X-API-Key`).
-- `list` / `get` / `usage` are read-only. `delete` is destructive but, like those
-  reads, is not gated by AgentPlan; `create` and `api-key` are gated.
+- `list` / `get` / `usage` are read-only; `delete` is destructive. Operations
+  on an existing library may require the AgentPlan key to be associated with it.
 - `get`/`usage`/`api-key`/`delete`/`update` and all `user *` take a `ResourceID`
   (e.g. `ov-xxxxxxxx`).
 - `user *` manages the multiple users of an **enterprise-tier** library and needs the
   AgentPlan key to be **associated with that library** (else the backend rejects it).
   `user list` returns each user's **masked** ApiKey; for a plaintext data-plane key
   use `api-key <ResourceID> --user-id <UserID>`.
+- Account operations also require the AgentPlan key to be associated with the target
+  library.
+- `--account-id` applies to `api-key`, `usage`, and every `user *` command; omitting
+  it selects account `default`. `usage --user-id <UserID>` is valid without it.
+- Scoped usage omits both `EstimatedCosts` and `EstimatedBilling`. Treat
+  account-list `CreateTime` as opaque.
 - Extra headers: pass `-H 'Key: Value'` (repeatable) or set `VIKING_EXTRA_HEADERS`
-  to a comma-separated `Key: Value` list — e.g. `-H 'x-tt-env: lujiakun'` for
+  to a comma-separated `Key: Value` list — e.g. `-H 'x-tt-env: <swimlane>'` for
   swim-lane routing. `Authorization` / `Content-Type` are protected and ignored.
diff --git a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/cli.py b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/cli.py
index a481afbc..5f549bf3 100644
--- a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/cli.py
+++ b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/cli.py
@@ -5,8 +5,15 @@
 
 import typer
 
-from mcp_server_openviking_controlplane.client import ControlPlaneClient, ControlPlaneError
+from mcp_server_openviking_controlplane.client import (
+    ControlPlaneClient,
+    ControlPlaneError,
+    _normalize_optional_account_id,
+    validate_account_id,
+)
 from mcp_server_openviking_controlplane.config import (
+    ACCOUNT_ID_RULES,
+    DEFAULT_ACCOUNT_ID,
     build_config,
     parse_extra_headers,
 )
@@ -84,7 +91,7 @@ def main_callback(
     header: Optional[List[str]] = typer.Option(
         None, "--header", "-H",
         help="Extra request header as 'Key: Value'; repeatable. Merged over "
-             "VIKING_EXTRA_HEADERS (CLI wins). E.g. -H 'x-tt-env: lujiakun' to "
+             "VIKING_EXTRA_HEADERS (CLI wins). E.g. -H 'x-tt-env: <swimlane>' to "
              "route into a swim-lane.",
     ),
     output: OutputMode = typer.Option(
@@ -142,11 +149,33 @@ def get_cmd(ctx: typer.Context, resource_id: str = typer.Argument(..., help="Tar
 
 
 @app.command("usage")
-def usage_cmd(ctx: typer.Context, resource_id: str = typer.Argument(..., help="Target library ResourceID.")):
-    """Get overall usage / file counts of a collection."""
+def usage_cmd(
+    ctx: typer.Context,
+    resource_id: str = typer.Argument(..., help="Target library ResourceID."),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) scope; omit for whole-library usage, or the "
+        "default data space when --user-id is set.",
+    ),
+    user_id: Optional[str] = typer.Option(
+        None,
+        "--user-id",
+        help="User whose usage to query; may be used with or without --account-id.",
+    ),
+):
+    """Get library-wide or account/user-scoped usage and file counts."""
     client = _client(ctx)
     try:
-        _print(ctx, client.get_usage(resource_id), "usage")
+        _print(
+            ctx,
+            client.get_usage(
+                resource_id,
+                account_id=account_id,
+                user_id=user_id,
+            ),
+            "usage",
+        )
     except Exception as e:
         raise _fail(e)
 
@@ -158,13 +187,26 @@ def api_key_cmd(
     user_id: Optional[str] = typer.Option(
         None,
         "--user-id",
-        help="Target UserID; omit for the default user.",
+        help="Target UserID; omit for the selected data space's default user.",
+    ),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) to operate in; omit for the default data space.",
     ),
 ):
     """Get a user's plaintext data-plane API Key."""
     client = _client(ctx)
     try:
-        _print(ctx, client.get_user_access(resource_id, user_id=user_id), "api-key")
+        _print(
+            ctx,
+            client.get_user_access(
+                resource_id,
+                user_id=user_id,
+                account_id=account_id,
+            ),
+            "api-key",
+        )
     except Exception as e:
         raise _fail(e)
 
@@ -299,6 +341,11 @@ def update_cmd(
 def user_list_cmd(
     ctx: typer.Context,
     resource_id: str = typer.Argument(..., help="Target library ResourceID."),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) to operate in; omit for the default data space.",
+    ),
     user_id: Optional[str] = typer.Option(
         None,
         "--user-id",
@@ -323,6 +370,7 @@ def user_list_cmd(
                 role=role,
                 page=page,
                 limit=limit,
+                account_id=account_id,
             ),
             "users",
         )
@@ -334,12 +382,21 @@ def user_list_cmd(
 def user_register_cmd(
     ctx: typer.Context,
     resource_id: str = typer.Argument(..., help="Target library ResourceID."),
-    user_id: str = typer.Argument(..., help="UserID for the new user (unique in library)."),
+    user_id: str = typer.Argument(..., help="UserID for the new user (unique in data space)."),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) to operate in; omit for the default data space.",
+    ),
 ):
     """Register a new regular user under a collection."""
     client = _client(ctx)
     try:
-        _print(ctx, client.register_user(resource_id, user_id), "success")
+        _print(
+            ctx,
+            client.register_user(resource_id, user_id, account_id=account_id),
+            "success",
+        )
     except Exception as e:
         raise _fail(e)
 
@@ -349,6 +406,11 @@ def user_update_cmd(
     ctx: typer.Context,
     resource_id: str = typer.Argument(..., help="Target library ResourceID."),
     user_id: str = typer.Argument(..., help="Target UserID."),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) to operate in; omit for the default data space.",
+    ),
     regenerate_key: bool = typer.Option(
         False,
         "--regenerate-key",
@@ -370,6 +432,7 @@ def user_update_cmd(
                 resource_id,
                 user_id,
                 regenerate_key=regenerate_key,
+                account_id=account_id,
             ),
             "success",
         )
@@ -382,17 +445,120 @@ def user_delete_cmd(
     ctx: typer.Context,
     resource_id: str = typer.Argument(..., help="Target library ResourceID."),
     user_id: str = typer.Argument(..., help="Target UserID."),
+    account_id: Optional[str] = typer.Option(
+        None,
+        "--account-id",
+        help="Data space (account) to operate in; omit for the default data space.",
+    ),
     yes: bool = typer.Option(False, "--yes", "-y", help="Skip the confirmation prompt."),
 ):
     """Delete a user from a collection (revokes its credential; irreversible)."""
     client = _client(ctx)
+    try:
+        normalized_account_id = _normalize_optional_account_id(account_id)
+    except Exception as e:
+        raise _fail(e)
+    if not yes:
+        typer.confirm(
+            f"Delete user {user_id} from data space {normalized_account_id or 'default'} "
+            f"in collection {resource_id} (revokes its credential)?",
+            abort=True,
+        )
+    try:
+        _print(
+            ctx,
+            client.delete_user(
+                resource_id,
+                user_id,
+                account_id=normalized_account_id,
+            ),
+            "success",
+        )
+    except Exception as e:
+        raise _fail(e)
+
+
+account_app = typer.Typer(
+    help=(
+        "Manage data spaces (accounts) within an enterprise-tier collection. "
+        "Omitting --account-id targets the default data space for user/API-key "
+        "commands; unscoped usage remains library-wide."
+    ),
+    no_args_is_help=True,
+)
+app.add_typer(account_app, name="account")
+
+
+@account_app.command("list")
+def account_list_cmd(
+    ctx: typer.Context,
+    resource_id: str = typer.Argument(..., help="Target library ResourceID."),
+    keyword: Optional[str] = typer.Option(
+        None,
+        "--keyword",
+        help="Filter data spaces by OpenVikingAccountID substring.",
+    ),
+    page: int = typer.Option(1, min=1, help="Page number (1-based)."),
+    limit: int = typer.Option(20, min=1, max=200, help="Data spaces per page."),
+):
+    """List data spaces under an enterprise-tier collection."""
+    client = _client(ctx)
+    try:
+        _print(
+            ctx,
+            client.list_accounts(
+                resource_id,
+                keyword=keyword,
+                page=page,
+                limit=limit,
+            ),
+            "accounts",
+        )
+    except Exception as e:
+        raise _fail(e)
+
+
+@account_app.command("create")
+def account_create_cmd(
+    ctx: typer.Context,
+    resource_id: str = typer.Argument(..., help="Target library ResourceID."),
+    account_id: str = typer.Argument(
+        ...,
+        help=f"OpenVikingAccountID for the new data space. {ACCOUNT_ID_RULES}",
+    ),
+):
+    """Create a data space; the backend also creates its default admin."""
+    client = _client(ctx)
+    try:
+        _print(ctx, client.create_account(resource_id, account_id), "success")
+    except Exception as e:
+        raise _fail(e)
+
+
+@account_app.command("delete")
+def account_delete_cmd(
+    ctx: typer.Context,
+    resource_id: str = typer.Argument(..., help="Target library ResourceID."),
+    account_id: str = typer.Argument(..., help="OpenVikingAccountID of the data space to delete."),
+    yes: bool = typer.Option(False, "--yes", "-y", help="Skip the confirmation prompt."),
+):
+    """Delete a data space and everything isolated inside it (irreversible)."""
+    client = _client(ctx)
+    try:
+        validated_account_id = validate_account_id(account_id)
+        if validated_account_id == DEFAULT_ACCOUNT_ID:
+            raise ValueError("the default account cannot be deleted")
+    except Exception as e:
+        raise _fail(e)
     if not yes:
         typer.confirm(
-            f"Delete user {user_id} from collection {resource_id} (revokes its credential)?",
+            f"Irreversibly delete data space {validated_account_id} from collection "
+            f"{resource_id}? This destroys ALL of its users, credentials, "
+            "memories, resources, sessions and skills.",
             abort=True,
         )
     try:
-        _print(ctx, client.delete_user(resource_id, user_id), "success")
+        _print(ctx, client.delete_account(resource_id, validated_account_id), "success")
     except Exception as e:
         raise _fail(e)
 
diff --git a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/client.py b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/client.py
index 1e7abba7..6479bb5d 100644
--- a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/client.py
+++ b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/client.py
@@ -7,6 +7,10 @@
 
 from mcp_server_openviking_controlplane.common.auth import AuthProvider, BearerTokenAuth
 from mcp_server_openviking_controlplane.config import (
+    ACCOUNT_ID_MAX_LENGTH,
+    ACCOUNT_ID_PATTERN,
+    ACCOUNT_ID_RULES,
+    DEFAULT_ACCOUNT_ID,
     DEFAULT_EMBEDDING_MODEL,
     DEFAULT_VLM_MODEL,
     PAY_TYPE_MAP,
@@ -126,6 +130,48 @@ def build_payment_config(
     }
 
 
+def validate_account_id(account_id: str, label: str = "account_id") -> str:
+    """Validate and return an OpenViking account (data-space) identifier."""
+    reason: Optional[str] = None
+    if not isinstance(account_id, str):
+        reason = "must be a string"
+    elif not 1 <= len(account_id) <= ACCOUNT_ID_MAX_LENGTH:
+        reason = f"must be between 1 and {ACCOUNT_ID_MAX_LENGTH} characters"
+    elif ACCOUNT_ID_PATTERN.fullmatch(account_id) is None:
+        reason = "contains unsupported characters"
+    elif account_id.startswith("_"):
+        reason = "must not start with '_'"
+    elif account_id in {".", ".."}:
+        reason = "must not be '.' or '..'"
+    elif account_id.count("@") > 1:
+        reason = "may contain at most one '@'"
+
+    if reason is not None:
+        raise ValueError(
+            f"invalid {label} {account_id!r}; {reason}. Rules: {ACCOUNT_ID_RULES}"
+        )
+    return account_id
+
+
+def _normalize_optional_account_id(account_id: Optional[str]) -> Optional[str]:
+    """Match the backend's optional account normalization for user actions."""
+    if account_id is None:
+        return None
+    if not isinstance(account_id, str):
+        return validate_account_id(account_id)
+    normalized = account_id.strip()
+    if not normalized:
+        return None
+    return validate_account_id(normalized)
+
+
+def _validate_pagination(page: int, limit: int) -> None:
+    if page < 1:
+        raise ValueError("page must be >= 1")
+    if not 1 <= limit <= 200:
+        raise ValueError("limit must be between 1 and 200")
+
+
 class ControlPlaneError(RuntimeError):
     """Raised when the control plane returns an Error envelope or a non-200 status."""
 
@@ -485,10 +531,28 @@ def _replay_note(cls, blocks: Dict[str, Any], explicit_key: bool) -> str:
     def delete_collection(self, resource_id: str) -> Dict[str, Any]:
         return self._request("DeleteOpenVikingCollection", {"ResourceID": resource_id})
 
-    def get_usage(self, resource_id: str) -> Dict[str, Any]:
-        result = self._request("GetOpenVikingUsage", {"ResourceID": resource_id})
+    def get_usage(
+        self,
+        resource_id: str,
+        account_id: Optional[str] = None,
+        user_id: Optional[str] = None,
+    ) -> Dict[str, Any]:
+        body: Dict[str, Any] = {"ResourceID": resource_id}
+        if account_id is not None:
+            body["OpenVikingAccountID"] = validate_account_id(account_id)
+        if user_id is not None:
+            # A UserID without an explicit account selects the default data space.
+            body["UserID"] = user_id
+        result = self._request("GetOpenVikingUsage", body)
         # AgentFileNum is not meaningful here; drop it from the returned usage.
         result.pop("AgentFileNum", None)
+        if account_id is not None or user_id is not None:
+            # Costs and collection metadata are library-wide. Attaching them to an
+            # account/user slice would be misleading, so scoped usage returns only
+            # scoped counters and avoids the extra collection request.
+            result.pop("EstimatedCosts", None)
+            result.pop("EstimatedBilling", None)
+            return result
         collection: Optional[Dict[str, Any]] = None
         try:
             collection = self.get_collection(resource_id)
@@ -506,6 +570,7 @@ def get_user_access(
         self,
         resource_id: str,
         user_id: Optional[str] = None,
+        account_id: Optional[str] = None,
     ) -> Dict[str, Any]:
         # On the data-plane cluster the api-key action is registered as
         # GetOpenVikingCollectionUserAccess (the console proxy's
@@ -516,6 +581,9 @@ def get_user_access(
         body: Dict[str, Any] = {"ResourceID": resource_id}
         if user_id is not None:
             body["UserID"] = user_id
+        normalized_account_id = _normalize_optional_account_id(account_id)
+        if normalized_account_id is not None:
+            body["OpenVikingAccountID"] = normalized_account_id
         return self._request("GetOpenVikingCollectionUserAccess", body)
 
     # --- User management (enterprise-tier libraries: multi-user) -------------
@@ -530,12 +598,10 @@ def list_collection_users(
         role: Optional[str] = None,
         page: int = 1,
         limit: int = 20,
+        account_id: Optional[str] = None,
     ) -> Dict[str, Any]:
         # ListOpenVikingCollectionUser: users under the library (ApiKey masked).
-        if page < 1:
-            raise ValueError("page must be >= 1")
-        if not 1 <= limit <= 200:
-            raise ValueError("limit must be between 1 and 200")
+        _validate_pagination(page, limit)
         body: Dict[str, Any] = {
             "ResourceID": resource_id,
             "Page": page,
@@ -545,17 +611,24 @@ def list_collection_users(
             body["UserID"] = user_id
         if role is not None:
             body["Role"] = role
+        normalized_account_id = _normalize_optional_account_id(account_id)
+        if normalized_account_id is not None:
+            body["OpenVikingAccountID"] = normalized_account_id
         return self._request("ListOpenVikingCollectionUser", body)
 
     def register_user(
         self,
         resource_id: str,
         user_id: str,
+        account_id: Optional[str] = None,
         extra: Optional[Dict[str, Any]] = None,
     ) -> Dict[str, Any]:
         # RegisterOpenVikingUser: create a regular "user" under the library.
         # The backend does not accept a Role parameter.
         body: Dict[str, Any] = {"ResourceID": resource_id, "UserID": user_id}
+        normalized_account_id = _normalize_optional_account_id(account_id)
+        if normalized_account_id is not None:
+            body["OpenVikingAccountID"] = normalized_account_id
         if extra:
             body.update(extra)
         return self._request("RegisterOpenVikingUser", body)
@@ -565,6 +638,7 @@ def update_user(
         resource_id: str,
         user_id: str,
         regenerate_key: bool = False,
+        account_id: Optional[str] = None,
         extra: Optional[Dict[str, Any]] = None,
     ) -> Dict[str, Any]:
         # UpdateOpenVikingUser only supports rotating the user's ApiKey.
@@ -577,14 +651,69 @@ def update_user(
             "UserID": user_id,
             "RegenerateKey": True,
         }
+        normalized_account_id = _normalize_optional_account_id(account_id)
+        if normalized_account_id is not None:
+            body["OpenVikingAccountID"] = normalized_account_id
         if extra:
             body.update(extra)
         return self._request("UpdateOpenVikingUser", body)
 
-    def delete_user(self, resource_id: str, user_id: str) -> Dict[str, Any]:
+    def delete_user(
+        self,
+        resource_id: str,
+        user_id: str,
+        account_id: Optional[str] = None,
+    ) -> Dict[str, Any]:
         # DeleteOpenVikingUser: remove a user from the library.
+        body: Dict[str, Any] = {"ResourceID": resource_id, "UserID": user_id}
+        normalized_account_id = _normalize_optional_account_id(account_id)
+        if normalized_account_id is not None:
+            body["OpenVikingAccountID"] = normalized_account_id
+        return self._request("DeleteOpenVikingUser", body)
+
+    # --- Account management (enterprise-tier data spaces) -------------------
+
+    def create_account(
+        self,
+        resource_id: str,
+        account_id: str,
+        extra: Optional[Dict[str, Any]] = None,
+    ) -> Dict[str, Any]:
+        body: Dict[str, Any] = {
+            "ResourceID": resource_id,
+            "OpenVikingAccountID": validate_account_id(account_id),
+        }
+        if extra:
+            body.update(extra)
+        return self._request("CreateOpenVikingAccount", body)
+
+    def list_accounts(
+        self,
+        resource_id: str,
+        keyword: Optional[str] = None,
+        page: int = 1,
+        limit: int = 20,
+    ) -> Dict[str, Any]:
+        _validate_pagination(page, limit)
+        body: Dict[str, Any] = {
+            "ResourceID": resource_id,
+            "Page": page,
+            "Limit": limit,
+        }
+        # Keyword is a substring filter, not an account identifier.
+        if keyword is not None:
+            body["Keyword"] = keyword
+        return self._request("ListOpenVikingAccounts", body)
+
+    def delete_account(self, resource_id: str, account_id: str) -> Dict[str, Any]:
+        account_id = validate_account_id(account_id)
+        # Mirror the backend guard before a caller crosses a destructive-confirmation
+        # boundary only to have the reserved default data space rejected remotely.
+        if account_id == DEFAULT_ACCOUNT_ID:
+            raise ValueError("the default account cannot be deleted")
         return self._request(
-            "DeleteOpenVikingUser", {"ResourceID": resource_id, "UserID": user_id}
+            "DeleteOpenVikingAccount",
+            {"ResourceID": resource_id, "OpenVikingAccountID": account_id},
         )
 
 
diff --git a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/config.py b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/config.py
index 9523dc71..ffe28cea 100644
--- a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/config.py
+++ b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/config.py
@@ -1,5 +1,6 @@
 import logging
 import os
+import re
 from dataclasses import dataclass, field
 from typing import Dict, Optional
 
@@ -32,6 +33,17 @@
 # tier; "enterprise" is the higher-capacity, enterprise-billed tier.
 VERSION_CHOICES = ("developer", "enterprise")
 
+# Account (data-space) identifiers are shared by account lifecycle operations
+# and account-aware user/usage operations.
+DEFAULT_ACCOUNT_ID = "default"
+ACCOUNT_ID_MAX_LENGTH = 64
+ACCOUNT_ID_PATTERN = re.compile(r"^[A-Za-z0-9_.@-]+$")
+ACCOUNT_ID_RULES = (
+    "must be 1-64 characters using only ASCII letters, digits, '_', '.', '@', or '-'; "
+    "must not start with '_'; must not be '.' or '..'; and may contain at most "
+    "one '@'"
+)
+
 # Billing (``PaymentConfig``): how a library is paid for — orthogonal to the
 # ``Version`` tier, which only sets the hourly rate. One flat user-facing enum
 # (the wire format splits it into PayType + AgentPlanConfig.BusinessScenarios);
diff --git a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/output.py b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/output.py
index 51353f64..d9489e93 100644
--- a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/output.py
+++ b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/output.py
@@ -56,6 +56,8 @@ def _pretty_renderable(result: Any, view: str) -> Any:
         return _collections_table(result.get("Collections"))
     if view == "users" and isinstance(result, dict):
         return _users_table(result.get("UserList"), result.get("Total"))
+    if view == "accounts" and isinstance(result, dict):
+        return _accounts_table(result.get("AccountList"), result.get("Total"))
     if view == "usage" and isinstance(result, dict):
         return _usage_panel(result)
     if view == "collection" and isinstance(result, dict):
@@ -120,6 +122,31 @@ def _users_table(rows: Any, total: Any) -> Any:
     return table
 
 
+def _accounts_table(rows: Any, total: Any) -> Any:
+    if not isinstance(rows, list):
+        return _generic_renderable({"AccountList": rows, "Total": total})
+    count = total if total is not None else len(rows)
+    table = Table(
+        title=f"Data Spaces ({count})",
+        box=box.ROUNDED,
+        header_style="bold cyan",
+    )
+    table.add_column("Account ID", style="bold")
+    table.add_column("Users")
+    table.add_column("Created")
+    table.add_column("Default")
+    for row in rows:
+        if not isinstance(row, dict):
+            continue
+        table.add_row(
+            _text(row.get("OpenVikingAccountID")),
+            _text(row.get("UserCount")),
+            _text(row.get("CreateTime")),
+            _value(row.get("IsDefault"), "IsDefault"),
+        )
+    return table
+
+
 def _usage_panel(result: Dict[str, Any]) -> Panel:
     files = Table.grid(padding=(0, 2))
     files.add_column(style="dim", no_wrap=True)
@@ -145,11 +172,19 @@ def _usage_panel(result: Dict[str, Any]) -> Panel:
                 "CNY equivalent",
                 f"¥{_text(billing.get('CNY'))} / {_period(billing)}",
             )
-    else:
+    elif "EstimatedCosts" in result:
         billing_table.add_row(
             "Estimated cost",
             f"¥{_text(result.get('EstimatedCosts'))} / hour",
         )
+    else:
+        billing_table.add_row(
+            "Estimated cost",
+            Text(
+                "— (reported for the whole library, not per data space)",
+                style="dim",
+            ),
+        )
 
     content = Group(
         Text("Context Files", style="bold cyan"),
diff --git a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/server.py b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/server.py
index b6ee8cdf..5d905784 100644
--- a/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/server.py
+++ b/server/mcp_server_openviking_controlplane/src/mcp_server_openviking_controlplane/server.py
@@ -11,6 +11,7 @@
     ControlPlaneError,
     build_client,
 )
+from mcp_server_openviking_controlplane.config import ACCOUNT_ID_RULES
 
 logger = logging.getLogger(__name__)
 logging.basicConfig(
@@ -128,22 +129,33 @@ def get_collection(
 
 @mcp.tool()
 def get_usage(
-    resource_id: str, ctx: Optional[Context] = None
+    resource_id: str,
+    account_id: Optional[str] = None,
+    user_id: Optional[str] = None,
+    ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
-    """Get overall usage / file counts for one OpenViking collection by ResourceID.
+    """Get library-wide or account/user-scoped usage and file counts.
 
     Args:
         resource_id: target library ResourceID.
+        account_id: optional data space (account) scope; omit for whole-library
+                    usage, or the default data space when user_id is supplied.
+        user_id: optional user scope; supported with or without account_id.
 
     Returns:
         {"CurContextFileNum", "ResourcesFileNum", "UserFileNum",
          "FreshTime" (Unix seconds), "EstimatedCosts", "EstimatedBilling"}.
-         EstimatedBilling adds CNY / hour plus PayType and, for AgentPlan
-         payment, the equivalent AFP / hour. Counts are whole-library + the
-         three top-level dirs only; per-uri breakdown is not supported.
+         For library-wide queries, EstimatedBilling adds CNY / hour plus PayType
+         and, for AgentPlan payment, the equivalent AFP / hour. Scoped responses
+         (when account_id and/or user_id is set) omit the library-wide
+         EstimatedCosts and EstimatedBilling because they would be misleading.
     """
     try:
-        return get_client(ctx).get_usage(resource_id)
+        return get_client(ctx).get_usage(
+            resource_id,
+            account_id=account_id,
+            user_id=user_id,
+        )
     except Exception as e:
         logger.error(f"get_usage failed: {e}")
         return _err(e)
@@ -153,25 +165,32 @@ def get_usage(
 def get_collection_api_key(
     resource_id: str,
     user_id: Optional[str] = None,
+    account_id: Optional[str] = None,
     ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
     """Get one user's plaintext data-plane API Key.
 
     Backed by the action GetOpenVikingCollectionUserAccess. When user_id is omitted,
-    returns the library's default-user credential; enterprise libraries can select
-    a specific user. You can only query libraries under your own account; there is
-    no cross-account / sudo lookup. NOTE: the ApiKey is plaintext — handle and
-    surface it with care.
+    returns the selected data space's default-user credential; enterprise libraries
+    can select a specific user. You can only query libraries associated with your
+    control-plane credential; there is no cross-owner / sudo lookup. NOTE: the
+    ApiKey is plaintext — handle and surface it with care.
 
     Args:
         resource_id: target library ResourceID.
-        user_id: optional target UserID; omit for the default user.
+        user_id: optional target UserID; omit for the selected data space's
+                 default user.
+        account_id: optional data space (account); omit for the default data space.
 
     Returns:
         {"UserID", "Role", "ApiKey"}
     """
     try:
-        return get_client(ctx).get_user_access(resource_id, user_id=user_id)
+        return get_client(ctx).get_user_access(
+            resource_id,
+            user_id=user_id,
+            account_id=account_id,
+        )
     except Exception as e:
         logger.error(f"get_collection_api_key failed: {e}")
         return _err(e)
@@ -307,6 +326,7 @@ def list_collection_users(
     role: Optional[str] = None,
     page: int = 1,
     limit: int = 20,
+    account_id: Optional[str] = None,
     ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
     """List the users registered under one OpenViking collection.
@@ -321,6 +341,7 @@ def list_collection_users(
         role: optional role filter, e.g. "admin" or "user".
         page: 1-based page number; defaults to 1.
         limit: users per page, 1 to 200; defaults to 20.
+        account_id: optional data space (account); omit for the default data space.
 
     Returns:
         {"UserList": [ {"UserID", "Role", "ApiKey" (masked)} ], "Total": N}
@@ -332,6 +353,7 @@ def list_collection_users(
             role=role,
             page=page,
             limit=limit,
+            account_id=account_id,
         )
     except Exception as e:
         logger.error(f"list_collection_users failed: {e}")
@@ -340,7 +362,10 @@ def list_collection_users(
 
 @mcp.tool()
 def register_collection_user(
-    resource_id: str, user_id: str, ctx: Optional[Context] = None
+    resource_id: str,
+    user_id: str,
+    account_id: Optional[str] = None,
+    ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
     """Register a NEW user under an OpenViking collection (RegisterOpenVikingUser).
 
@@ -350,13 +375,18 @@ def register_collection_user(
 
     Args:
         resource_id: target library ResourceID.
-        user_id: the UserID for the new user (unique within the library).
+        user_id: the UserID for the new user (unique within the data space).
+        account_id: optional data space (account); omit for the default data space.
 
     Returns:
         {"Success": true}
     """
     try:
-        return get_client(ctx).register_user(resource_id, user_id)
+        return get_client(ctx).register_user(
+            resource_id,
+            user_id,
+            account_id=account_id,
+        )
     except Exception as e:
         logger.error(f"register_collection_user failed: {e}")
         return _err(e)
@@ -367,6 +397,7 @@ def update_collection_user(
     resource_id: str,
     user_id: str,
     regenerate_key: bool,
+    account_id: Optional[str] = None,
     ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
     """Update a user under an OpenViking collection (currently API Key rotation).
@@ -379,6 +410,7 @@ def update_collection_user(
         resource_id: target library ResourceID.
         user_id: the UserID to update.
         regenerate_key: true to rotate the user's data-plane API Key.
+        account_id: optional data space (account); omit for the default data space.
 
     Returns:
         {"Success": true}
@@ -388,6 +420,7 @@ def update_collection_user(
             resource_id,
             user_id,
             regenerate_key=regenerate_key,
+            account_id=account_id,
         )
     except Exception as e:
         logger.error(f"update_collection_user failed: {e}")
@@ -396,7 +429,10 @@ def update_collection_user(
 
 @mcp.tool()
 def delete_collection_user(
-    resource_id: str, user_id: str, ctx: Optional[Context] = None
+    resource_id: str,
+    user_id: str,
+    account_id: Optional[str] = None,
+    ctx: Optional[Context] = None,
 ) -> Dict[str, Any]:
     """⚠️ Delete a user from an OpenViking collection (DeleteOpenVikingUser).
 
@@ -406,17 +442,119 @@ def delete_collection_user(
     Args:
         resource_id: target library ResourceID.
         user_id: the UserID to delete.
+        account_id: optional data space (account); omit for the default data space.
 
     Returns:
         {"Success": true}
     """
     try:
-        return get_client(ctx).delete_user(resource_id, user_id)
+        return get_client(ctx).delete_user(
+            resource_id,
+            user_id,
+            account_id=account_id,
+        )
     except Exception as e:
         logger.error(f"delete_collection_user failed: {e}")
         return _err(e)
 
 
+@mcp.tool()
+def list_collection_accounts(
+    resource_id: str,
+    keyword: Optional[str] = None,
+    page: int = 1,
+    limit: int = 20,
+    ctx: Optional[Context] = None,
+) -> Dict[str, Any]:
+    """List data spaces (accounts) under an enterprise-tier collection.
+
+    Args:
+        resource_id: target library ResourceID.
+        keyword: optional OpenVikingAccountID substring filter.
+        page: 1-based page number; defaults to 1.
+        limit: data spaces per page, 1 to 200; defaults to 20.
+
+    Returns:
+        {"AccountList": [{"OpenVikingAccountID", "UserCount", "CreateTime",
+         "IsDefault"}], "Total": N}
+    """
+    try:
+        return get_client(ctx).list_accounts(
+            resource_id,
+            keyword=keyword,
+            page=page,
+            limit=limit,
+        )
+    except Exception as e:
+        logger.error(f"list_collection_accounts failed: {e}")
+        return _err(e)
+
+
+@mcp.tool(
+    description=(
+        "Create a data space (account), an isolation boundary within a library. "
+        "CONFIRM WITH THE USER before calling. The backend creates a default "
+        "admin in the new data space; the per-library account limit is "
+        f"backend-configured. OpenVikingAccountID {ACCOUNT_ID_RULES}."
+    )
+)
+def create_collection_account(
+    resource_id: str,
+    account_id: str,
+    ctx: Optional[Context] = None,
+) -> Dict[str, Any]:
+    """Create a data space (account), an isolation boundary within a library.
+
+    CONFIRM WITH THE USER before calling. This enterprise-tier capability creates
+    a separate boundary for users, credentials, memories, resources, sessions,
+    and skills. The backend automatically creates a ``default`` admin inside the
+    new data space. The per-library account limit is backend-configured.
+
+    OpenVikingAccountID is validated locally: it must be 1-64 characters using only
+    letters, digits, '_', '.', '@', or '-'; must not start with '_'; must not
+    be '.' or '..'; and may contain at most one '@'.
+
+    Args:
+        resource_id: target library ResourceID.
+        account_id: OpenVikingAccountID for the new data space.
+
+    Returns:
+        {"Success": true, "OpenVikingAccountID": "..."}
+    """
+    try:
+        return get_client(ctx).create_account(resource_id, account_id)
+    except Exception as e:
+        logger.error(f"create_collection_account failed: {e}")
+        return _err(e)
+
+
+@mcp.tool()
+def delete_collection_account(
+    resource_id: str,
+    account_id: str,
+    ctx: Optional[Context] = None,
+) -> Dict[str, Any]:
+    """⚠️ IRREVERSIBLY delete a data space and all isolated data inside it.
+
+    CONFIRM WITH THE USER before calling. Deletion cascades through ALL users,
+    credentials, memories, resources, sessions, and skills in the data space.
+    The ``default`` data space cannot be deleted; both the client and backend
+    reject it.
+
+    Args:
+        resource_id: target library ResourceID.
+        account_id: OpenVikingAccountID of the data space to delete.
+
+    Returns:
+        {"Success": true}
+    """
+    try:
+        return get_client(ctx).delete_account(resource_id, account_id)
+    except Exception as e:
+        logger.error(f"delete_collection_account failed: {e}")
+        return _err(e)
+
+
 @mcp.tool()
 def delete_collection(
     resource_id: str, ctx: Optional[Context] = None
diff --git a/server/mcp_server_openviking_controlplane/tests/test_account_contract.py b/server/mcp_server_openviking_controlplane/tests/test_account_contract.py
new file mode 100644
index 00000000..2b710295
--- /dev/null
+++ b/server/mcp_server_openviking_controlplane/tests/test_account_contract.py
@@ -0,0 +1,693 @@
+import inspect
+import unittest
+from unittest.mock import patch
+
+from typer.testing import CliRunner
+
+from mcp_server_openviking_controlplane import cli, server
+from mcp_server_openviking_controlplane.cli import app
+from mcp_server_openviking_controlplane.client import (
+    ControlPlaneClient,
+    ControlPlaneError,
+    validate_account_id,
+)
+from mcp_server_openviking_controlplane.config import ControlPlaneConfig
+
+
+class AccountClientContractTest(unittest.TestCase):
+    def setUp(self):
+        self.client = ControlPlaneClient(ControlPlaneConfig(api_key="ark-test"))
+
+    def test_create_account_sends_exact_wire_body(self):
+        with patch.object(
+            self.client,
+            "_request",
+            return_value={"Success": True, "OpenVikingAccountID": "team.alpha"},
+        ) as request:
+            result = self.client.create_account(
+                "ov-example",
+                "team.alpha",
+                extra={"TraceTag": "test"},
+            )
+
+        self.assertEqual(result["OpenVikingAccountID"], "team.alpha")
+        request.assert_called_once_with(
+            "CreateOpenVikingAccount",
+            {
+                "ResourceID": "ov-example",
+                "OpenVikingAccountID": "team.alpha",
+                "TraceTag": "test",
+            },
+        )
+
+    def test_list_accounts_omits_keyword_by_default(self):
+        with patch.object(
+            self.client,
+            "_request",
+            return_value={"AccountList": [], "Total": 0},
+        ) as request:
+            self.client.list_accounts("ov-example")
+
+        request.assert_called_once_with(
+            "ListOpenVikingAccounts",
+            {"ResourceID": "ov-example", "Page": 1, "Limit": 20},
+        )
+
+    def test_list_accounts_forwards_keyword_and_pagination(self):
+        with patch.object(
+            self.client,
+            "_request",
+            return_value={"AccountList": [], "Total": 0},
+        ) as request:
+            self.client.list_accounts(
+                "ov-example",
+                keyword="team alpha",
+                page=2,
+                limit=10,
+            )
+
+        request.assert_called_once_with(
+            "ListOpenVikingAccounts",
+            {
+                "ResourceID": "ov-example",
+                "Keyword": "team alpha",
+                "Page": 2,
+                "Limit": 10,
+            },
+        )
+
+    def test_list_accounts_validates_pagination_locally(self):
+        for kwargs, message in (
+            ({"page": 0}, "page must be >= 1"),
+            ({"limit": 0}, "limit must be between 1 and 200"),
+            ({"limit": 201}, "limit must be between 1 and 200"),
+        ):
+            with self.subTest(kwargs=kwargs):
+                with self.assertRaisesRegex(ValueError, message):
+                    self.client.list_accounts("ov-example", **kwargs)
+
+    def test_delete_account_rejects_default_before_request(self):
+        with patch.object(self.client, "_request") as request:
+            with self.assertRaisesRegex(ValueError, "default.*cannot be deleted"):
+                self.client.delete_account("ov-example", "default")
+
+        request.assert_not_called()
+
+    def test_delete_account_sends_exact_wire_body(self):
+        with patch.object(
+            self.client,
+            "_request",
+            return_value={"Success": True},
+        ) as request:
+            self.client.delete_account("ov-example", "team-alpha")
+
+        request.assert_called_once_with(
+            "DeleteOpenVikingAccount",
+            {"ResourceID": "ov-example", "OpenVikingAccountID": "team-alpha"},
+        )
+
+    def test_account_id_validation_rejects_invalid_values(self):
+        invalid_values = (
+            None,
+            7,
+            "",
+            "a" * 65,
+            "team alpha",
+            "中文",
+            "_private",
+            ".",
+            "..",
+            "a@b@c",
+        )
+        for value in invalid_values:
+            with self.subTest(value=value):
+                with self.assertRaisesRegex(ValueError, "Rules:"):
+                    validate_account_id(value)
+
+    def test_account_id_validation_accepts_boundaries_and_supported_characters(self):
+        for value in ("a", "a" * 64, "team.alpha-1_x", "user@corp"):
+            with self.subTest(value=value):
+                self.assertEqual(validate_account_id(value), value)
+
+    def test_existing_user_actions_omit_account_id_for_legacy_wire_compatibility(self):
+        calls = (
+            (
+                lambda: self.client.get_user_access("ov-example"),
+                "GetOpenVikingCollectionUserAccess",
+                {"ResourceID": "ov-example"},
+            ),
+            (
+                lambda: self.client.list_collection_users("ov-example"),
+                "ListOpenVikingCollectionUser",
+                {"ResourceID": "ov-example", "Page": 1, "Limit": 20},
+            ),
+            (
+                lambda: self.client.register_user("ov-example", "alice"),
+                "RegisterOpenVikingUser",
+                {"ResourceID": "ov-example", "UserID": "alice"},
+            ),
+            (
+                lambda: self.client.update_user("ov-example", "alice", True),
+                "UpdateOpenVikingUser",
+                {"ResourceID": "ov-example", "UserID": "alice", "RegenerateKey": True},
+            ),
+            (
+                lambda: self.client.delete_user("ov-example", "alice"),
+                "DeleteOpenVikingUser",
+                {"ResourceID": "ov-example", "UserID": "alice"},
+            ),
+        )
+        for call, action, body in calls:
+            with self.subTest(action=action):
+                with patch.object(self.client, "_request", return_value={}) as request:
+                    call()
+                request.assert_called_once_with(action, body)
+
+    def test_existing_user_actions_forward_validated_account_id(self):
+        calls = (
+            (
+                lambda: self.client.get_user_access("ov-example", account_id="team"),
+                "GetOpenVikingCollectionUserAccess",
+                {"ResourceID": "ov-example", "OpenVikingAccountID": "team"},
+            ),
+            (
+                lambda: self.client.list_collection_users(
+                    "ov-example", account_id="team"
+                ),
+                "ListOpenVikingCollectionUser",
+                {
+                    "ResourceID": "ov-example",
+                    "Page": 1,
+                    "Limit": 20,
+                    "OpenVikingAccountID": "team",
+                },
+            ),
+            (
+                lambda: self.client.register_user(
+                    "ov-example", "alice", account_id="team"
+                ),
+                "RegisterOpenVikingUser",
+                {"ResourceID": "ov-example", "UserID": "alice", "OpenVikingAccountID": "team"},
+            ),
+            (
+                lambda: self.client.update_user(
+                    "ov-example", "alice", True, account_id="team"
+                ),
+                "UpdateOpenVikingUser",
+                {
+                    "ResourceID": "ov-example",
+                    "UserID": "alice",
+                    "RegenerateKey": True,
+                    "OpenVikingAccountID": "team",
+                },
+            ),
+            (
+                lambda: self.client.delete_user(
+                    "ov-example", "alice", account_id="team"
+                ),
+                "DeleteOpenVikingUser",
+                {"ResourceID": "ov-example", "UserID": "alice", "OpenVikingAccountID": "team"},
+            ),
+        )
+        for call, action, body in calls:
+            with self.subTest(action=action):
+                with patch.object(self.client, "_request", return_value={}) as request:
+                    call()
+                request.assert_called_once_with(action, body)
+
+    def test_existing_user_actions_normalize_optional_account_id(self):
+        calls = (
+            lambda value: self.client.get_user_access("ov-example", account_id=value),
+            lambda value: self.client.list_collection_users(
+                "ov-example", account_id=value
+            ),
+            lambda value: self.client.register_user(
+                "ov-example", "alice", account_id=value
+            ),
+            lambda value: self.client.update_user(
+                "ov-example", "alice", True, account_id=value
+            ),
+            lambda value: self.client.delete_user(
+                "ov-example", "alice", account_id=value
+            ),
+        )
+        for call in calls:
+            with self.subTest(call=call, value="blank"):
+                with patch.object(self.client, "_request", return_value={}) as request:
+                    call("   ")
+                self.assertNotIn("OpenVikingAccountID", request.call_args.args[1])
+            with self.subTest(call=call, value="trimmed"):
+                with patch.object(self.client, "_request", return_value={}) as request:
+                    call(" team ")
+                self.assertEqual(request.call_args.args[1]["OpenVikingAccountID"], "team")
+
+    def test_existing_actions_reject_invalid_account_id_before_request(self):
+        calls = (
+            lambda: self.client.get_user_access("ov-example", account_id="bad value"),
+            lambda: self.client.get_user_access("ov-example", account_id=7),
+            lambda: self.client.list_collection_users(
+                "ov-example", account_id="bad value"
+            ),
+            lambda: self.client.register_user(
+                "ov-example", "alice", account_id="bad value"
+            ),
+            lambda: self.client.update_user(
+                "ov-example", "alice", True, account_id="bad value"
+            ),
+            lambda: self.client.delete_user(
+                "ov-example", "alice", account_id="bad value"
+            ),
+            lambda: self.client.get_usage("ov-example", account_id="bad value"),
+        )
+        with patch.object(self.client, "_request") as request:
+            for call in calls:
+                with self.subTest(call=call):
+                    with self.assertRaisesRegex(ValueError, "Rules:"):
+                        call()
+            request.assert_not_called()
+
+    def test_scoped_usage_uses_backend_field_and_removes_library_billing(self):
+        backend_result = {
+            "CurContextFileNum": 3,
+            "AgentFileNum": 9,
+            "EstimatedCosts": "0.05",
+            "EstimatedBilling": {"CNY": "0.05"},
+        }
+        with patch.object(
+            self.client, "_request", return_value=backend_result
+        ) as request:
+            result = self.client.get_usage(
+                "ov-example",
+                account_id="team",
+                user_id="alice",
+            )
+
+        request.assert_called_once_with(
+            "GetOpenVikingUsage",
+            {
+                "ResourceID": "ov-example",
+                "OpenVikingAccountID": "team",
+                "UserID": "alice",
+            },
+        )
+        self.assertEqual(result, {"CurContextFileNum": 3})
+
+    def test_usage_allows_user_only_scope_in_default_account(self):
+        with patch.object(
+            self.client,
+            "_request",
+            return_value={"CurContextFileNum": 1, "EstimatedCosts": "0.05"},
+        ) as request:
+            result = self.client.get_usage("ov-example", user_id="alice")
+
+        request.assert_called_once_with(
+            "GetOpenVikingUsage",
+            {"ResourceID": "ov-example", "UserID": "alice"},
+        )
+        self.assertNotIn("EstimatedCosts", result)
+
+    def test_unscoped_usage_preserves_legacy_wire_body_and_enrichment(self):
+        with patch.object(
+            self.client,
+            "_request",
+            side_effect=[
+                {"AgentFileNum": 9, "EstimatedCosts": "0.05"},
+                {},
+            ],
+        ) as request:
+            result = self.client.get_usage("ov-example")
+
+        self.assertEqual(
+            request.call_args_list[0].args,
+            ("GetOpenVikingUsage", {"ResourceID": "ov-example"}),
+        )
+        self.assertNotIn("AgentFileNum", result)
+        self.assertEqual(result["EstimatedBilling"]["CNY"], "0.05")
+
+
+class AccountCliContractTest(unittest.TestCase):
+    def setUp(self):
+        self.runner = CliRunner()
+        self.prefix = ["--api-key", "ark-test", "--json"]
+
+    def test_account_list_forwards_filters_and_pagination(self):
+        with patch(
+            "mcp_server_openviking_controlplane.cli.ControlPlaneClient.list_accounts",
+            return_value={"AccountList": [], "Total": 0},
+        ) as list_accounts:
+            result = self.runner.invoke(
+                app,
+                self.prefix
+                + [
+                    "account",
+                    "list",
+                    "ov-example",
+                    "--keyword",
+                    "team",
+                    "--page",
+                    "2",
+                    "--limit",
+                    "10",
+                ],
+            )
+
+        self.assertEqual(result.exit_code, 0)
+        list_accounts.assert_called_once_with(
+            "ov-example", keyword="team", page=2, limit=10
+        )
+
+    def test_account_create_forwards_identifiers(self):
+        with patch(
+            "mcp_server_openviking_controlplane.cli.ControlPlaneClient.create_account",
+            return_value={"Success": True, "OpenVikingAccountID": "team"},
+        ) as create_account:
+            result = self.runner.invoke(
+                app,
+                self.prefix + ["account", "create", "ov-example", "team"],
+            )
+
+        self.assertEqual(result.exit_code, 0)
+        create_account.assert_called_once_with("ov-example", "team")
+
+    def test_account_create_reports_validation_error_without_traceback(self):
+        result = self.runner.invoke(
+            app,
+            self.prefix + ["account", "create", "ov-example", "team alpha"],
+        )
+
+        self.assertEqual(result.exit_code, 1)
+        self.assertIn("Rules:", result.output)
+        self.assertNotIn("Traceback", result.output)
+
+    def test_account_delete_confirmation_can_abort_without_calling_backend(self):
+        with patch(
+            "mcp_server_openviking_controlplane.cli.ControlPlaneClient.delete_account"
+        ) as delete_account:
+            result = self.runner.invoke(
+                app,
+                self.prefix + ["account", "delete", "ov-example", "team"],
+                input="n\n",
+            )
+
+        self.assertEqual(result.exit_code, 1)
+        self.assertIn("Aborted", result.output)
+        delete_account.assert_not_called()
+
+    def test_account_delete_rejects_default_before_prompt_or_backend_call(self):
+        with patch(
+            "mcp_server_openviking_controlplane.cli.ControlPlaneClient.delete_account"
+        ) as delete_account:
+            result = self.runner.invoke(
+                app,
+                self.prefix + ["account", "delete", "ov-example", "default"],
+            )
+
+        self.assertEqual(result.exit_code, 1)
+        self.assertIn("default account cannot be deleted", result.output)
+        self.assertNotIn("[y/N]", result.output)
+        delete_account.assert_not_called()
+
+    def test_account_delete_confirmation_and_yes_flag_call_backend(self):
+        for suffix, input_text in (([], "y\n"), (["--yes"], None)):
+            with self.subTest(suffix=suffix):
+                with patch(
+                    "mcp_server_openviking_controlplane.cli.ControlPlaneClient.delete_account",
+                    return_value={"Success": True},
+                ) as delete_account:
+                    result = self.runner.invoke(
+                        app,
+                        self.prefix
+                        + ["account", "delete", "ov-example", "team"]
+                        + suffix,
+                        input=input_text,
+                    )
+
+                self.assertEqual(result.exit_code, 0)
+                delete_account.assert_called_once_with("ov-example", "team")
+
+    def test_user_delete_confirms_and_forwards_normalized_account_id(self):
+        for raw_account_id, expected_account_id in ((" team ", "team"), ("   ", None)):
+            with self.subTest(raw_account_id=raw_account_id):
+                with patch(
+                    "mcp_server_openviking_controlplane.cli.ControlPlaneClient.delete_user",
+                    return_value={"Success": True},
+                ) as delete_user:
+                    result = self.runner.invoke(
+                        app,
+                        self.prefix
+                        + [
+                            "user",
+                            "delete",
+                            "ov-example",
+                            "alice",
+                            "--account-id",
+                            raw_account_id,
+                        ],
+                        input="n\n",
+                    )
+
+                self.assertEqual(result.exit_code, 1)
+                self.assertIn(
+                    f"data space {expected_account_id or 'default'}", result.output
+                )
+                delete_user.assert_not_called()
+
+                with patch(
+                    "mcp_server_openviking_controlplane.cli.ControlPlaneClient.delete_user",
+                    return_value={"Success": True},
+                ) as delete_user:
+                    result = self.runner.invoke(
+                        app,
+                        self.prefix
+                        + [
+                            "user",
+                            "delete",
+                            "ov-example",
+                            "alice",
+                            "--account-id",
+                            raw_account_id,
+                            "--yes",
+                        ],
+                    )
+
+                self.assertEqual(result.exit_code, 0)
+                delete_user.assert_called_once_with(
+                    "ov-example", "alice", account_id=expected_account_id
+                )
+
+    def test_scoped_existing_commands_forward_account_and_user(self):
+        cases = (
+            (
+                "get_user_access",
+                ["api-key", "ov-example", "--account-id", "team", "--user-id", "alice"],
+                ("ov-example",),
+                {"user_id": "alice", "account_id": "team"},
+                {"ApiKey": "plain"},
+            ),
+            (
+                "get_usage",
+                ["usage", "ov-example", "--account-id", "team", "--user-id", "alice"],
+                ("ov-example",),
+                {"account_id": "team", "user_id": "alice"},
+                {"CurContextFileNum": 1},
+            ),
+            (
+                "list_collection_users",
+                ["user", "list", "ov-example", "--account-id", "team"],
+                ("ov-example",),
+                {
+                    "user_id": None,
+                    "role": None,
+                    "page": 1,
+                    "limit": 20,
+                    "account_id": "team",
+                },
+                {"UserList": [], "Total": 0},
+            ),
+            (
+                "register_user",
+                ["user", "register", "ov-example", "alice", "--account-id", "team"],
+                ("ov-example", "alice"),
+                {"account_id": "team"},
+                {"Success": True},
+            ),
+            (
+                "update_user",
+                [
+                    "user",
+                    "update",
+                    "ov-example",
+                    "alice",
+                    "--regenerate-key",
+                    "--account-id",
+                    "team",
+                ],
+                ("ov-example", "alice"),
+                {"regenerate_key": True, "account_id": "team"},
+                {"Success": True},
+            ),
+            (
+                "delete_user",
+                [
+                    "user",
+                    "delete",
+                    "ov-example",
+                    "alice",
+                    "--account-id",
+                    "team",
+                    "--yes",
+                ],
+                ("ov-example", "alice"),
+                {"account_id": "team"},
+                {"Success": True},
+            ),
+        )
+        for method, argv, args, kwargs, response in cases:
+            with self.subTest(method=method):
+                with patch(
+                    f"mcp_server_openviking_controlplane.cli.ControlPlaneClient.{method}",
+                    return_value=response,
+                ) as call:
+                    result = self.runner.invoke(app, self.prefix + argv)
+                self.assertEqual(result.exit_code, 0, result.output)
+                call.assert_called_once_with(*args, **kwargs)
+
+
+class AccountMcpContractTest(unittest.TestCase):
+    def test_account_tools_forward_all_arguments(self):
+        with patch.object(server, "get_client") as get_client:
+            client = get_client.return_value
+            client.list_accounts.return_value = {"AccountList": [], "Total": 0}
+            client.create_account.return_value = {"Success": True}
+            client.delete_account.return_value = {"Success": True}
+
+            server.list_collection_accounts(
+                "ov-example", keyword="team", page=2, limit=10
+            )
+            server.create_collection_account("ov-example", "team")
+            server.delete_collection_account("ov-example", "team")
+
+        client.list_accounts.assert_called_once_with(
+            "ov-example", keyword="team", page=2, limit=10
+        )
+        client.create_account.assert_called_once_with("ov-example", "team")
+        client.delete_account.assert_called_once_with("ov-example", "team")
+
+    def test_existing_tools_forward_scope(self):
+        with patch.object(server, "get_client") as get_client:
+            client = get_client.return_value
+            server.get_usage("ov-example", account_id="team", user_id="alice")
+            server.get_collection_api_key(
+                "ov-example", user_id="alice", account_id="team"
+            )
+            server.list_collection_users(
+                "ov-example", account_id="team", page=2, limit=10
+            )
+            server.register_collection_user("ov-example", "alice", account_id="team")
+            server.update_collection_user(
+                "ov-example", "alice", regenerate_key=True, account_id="team"
+            )
+            server.delete_collection_user("ov-example", "alice", account_id="team")
+
+        client.get_usage.assert_called_once_with(
+            "ov-example", account_id="team", user_id="alice"
+        )
+        client.get_user_access.assert_called_once_with(
+            "ov-example", user_id="alice", account_id="team"
+        )
+        client.list_collection_users.assert_called_once_with(
+            "ov-example",
+            user_id=None,
+            role=None,
+            page=2,
+            limit=10,
+            account_id="team",
+        )
+        client.register_user.assert_called_once_with(
+            "ov-example", "alice", account_id="team"
+        )
+        client.update_user.assert_called_once_with(
+            "ov-example", "alice", regenerate_key=True, account_id="team"
+        )
+        client.delete_user.assert_called_once_with(
+            "ov-example", "alice", account_id="team"
+        )
+
+    def test_account_tools_return_structured_errors(self):
+        cases = (
+            (
+                "list_accounts",
+                lambda: server.list_collection_accounts("ov-example"),
+                ControlPlaneError("Denied", "not allowed", "req-1"),
+                {
+                    "error": {
+                        "code": "Denied",
+                        "message": "not allowed",
+                        "request_id": "req-1",
+                    }
+                },
+            ),
+            (
+                "create_account",
+                lambda: server.create_collection_account("ov-example", "bad value"),
+                ValueError("invalid account_id"),
+                {"error": {"message": "invalid account_id"}},
+            ),
+        )
+        for method, call, error, expected in cases:
+            with self.subTest(method=method):
+                with patch.object(server, "get_client") as get_client:
+                    getattr(get_client.return_value, method).side_effect = error
+                    self.assertEqual(call(), expected)
+
+    def test_public_signatures_expose_scope_and_keep_context_last(self):
+        client_methods = (
+            "get_usage",
+            "get_user_access",
+            "list_collection_users",
+            "register_user",
+            "update_user",
+            "delete_user",
+        )
+        for name in client_methods:
+            with self.subTest(layer="client", name=name):
+                params = inspect.signature(getattr(ControlPlaneClient, name)).parameters
+                self.assertIn("account_id", params)
+        self.assertIn(
+            "user_id", inspect.signature(ControlPlaneClient.get_usage).parameters
+        )
+
+        cli_commands = (
+            "usage_cmd",
+            "api_key_cmd",
+            "user_list_cmd",
+            "user_register_cmd",
+            "user_update_cmd",
+            "user_delete_cmd",
+        )
+        for name in cli_commands:
+            with self.subTest(layer="cli", name=name):
+                params = inspect.signature(getattr(cli, name)).parameters
+                self.assertIn("account_id", params)
+        self.assertIn("user_id", inspect.signature(cli.usage_cmd).parameters)
+
+        server_tools = (
+            "get_usage",
+            "get_collection_api_key",
+            "list_collection_users",
+            "register_collection_user",
+            "update_collection_user",
+            "delete_collection_user",
+            "list_collection_accounts",
+            "create_collection_account",
+            "delete_collection_account",
+        )
+        for name in server_tools:
+            with self.subTest(layer="server", name=name):
+                params = inspect.signature(getattr(server, name)).parameters
+                self.assertEqual(next(reversed(params)), "ctx")
+        self.assertIn("user_id", inspect.signature(server.get_usage).parameters)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/server/mcp_server_openviking_controlplane/tests/test_output.py b/server/mcp_server_openviking_controlplane/tests/test_output.py
index ae9a9538..30aff9ce 100644
--- a/server/mcp_server_openviking_controlplane/tests/test_output.py
+++ b/server/mcp_server_openviking_controlplane/tests/test_output.py
@@ -100,6 +100,45 @@ def test_collection_table_wraps_in_a_narrow_terminal(self):
         self.assertIn("demo", output)
         self.assertIn("READY", output)
 
+    def test_account_table_renders_count_timestamp_and_boolean(self):
+        data = {
+            "AccountList": [
+                {
+                    "OpenVikingAccountID": "default",
+                    "UserCount": 3,
+                    "CreateTime": "2026-08-27T12:34:56Z",
+                    "IsDefault": True,
+                },
+                {
+                    "OpenVikingAccountID": "team-a",
+                    "UserCount": 1,
+                    "CreateTime": "1732100000",
+                    "IsDefault": False,
+                },
+            ],
+            "Total": 2,
+        }
+
+        output = self.render(data, mode=OutputMode.PRETTY, view="accounts")
+
+        self.assertIn("Data Spaces (2)", output)
+        self.assertIn("default", output)
+        self.assertIn("team-a", output)
+        self.assertIn("yes", output)
+        self.assertIn("no", output)
+        self.assertIn("2026-08-27T12:34:56Z", output)
+        self.assertIn("1732100000", output)
+
+    def test_scoped_usage_does_not_render_library_billing_placeholder(self):
+        output = self.render(
+            {"CurContextFileNum": 12, "ResourcesFileNum": 4},
+            mode=OutputMode.PRETTY,
+            view="usage",
+        )
+
+        self.assertIn("reported for the whole library, not per data space", output)
+        self.assertNotIn("¥—", output)
+
     def test_api_key_view_warns_that_the_value_is_sensitive(self):
         output = self.render(
             {"UserID": "default", "Role": "admin", "ApiKey": "secret-key"},
diff --git a/server/mcp_server_openviking_controlplane/tests/test_server_transport.py b/server/mcp_server_openviking_controlplane/tests/test_server_transport.py
index e0fee6d7..8b6f1784 100644
--- a/server/mcp_server_openviking_controlplane/tests/test_server_transport.py
+++ b/server/mcp_server_openviking_controlplane/tests/test_server_transport.py
@@ -143,7 +143,25 @@ def test_ctx_is_not_exposed_as_a_tool_argument(self):
         import anyio
 
         tools = anyio.run(server.mcp.list_tools)
-        self.assertEqual(len(tools), 11)
+        self.assertEqual(
+            {tool.name for tool in tools},
+            {
+                "list_collections",
+                "get_collection",
+                "get_usage",
+                "get_collection_api_key",
+                "create_collection",
+                "update_collection",
+                "list_collection_users",
+                "register_collection_user",
+                "update_collection_user",
+                "delete_collection_user",
+                "list_collection_accounts",
+                "create_collection_account",
+                "delete_collection_account",
+                "delete_collection",
+            },
+        )
         for tool in tools:
             with self.subTest(tool=tool.name):
                 self.assertNotIn("ctx", tool.input_schema.get("properties") or {})
diff --git a/server/mcp_server_openviking_controlplane/tests/test_user_contract.py b/server/mcp_server_openviking_controlplane/tests/test_user_contract.py
index f9839404..40b087fd 100644
--- a/server/mcp_server_openviking_controlplane/tests/test_user_contract.py
+++ b/server/mcp_server_openviking_controlplane/tests/test_user_contract.py
@@ -121,7 +121,9 @@ def test_api_key_accepts_user_id(self):
             )
 
         self.assertEqual(result.exit_code, 0)
-        get_user_access.assert_called_once_with("ov-example", user_id="alice")
+        get_user_access.assert_called_once_with(
+            "ov-example", user_id="alice", account_id=None
+        )
 
     def test_user_list_accepts_filters_and_pagination(self):
         with patch(
@@ -155,6 +157,7 @@ def test_user_list_accepts_filters_and_pagination(self):
             role="user",
             page=2,
             limit=10,
+            account_id=None,
         )
 
     def test_user_update_requires_regenerate_key(self):
@@ -192,6 +195,7 @@ def test_api_key_tool_forwards_user_id(self):
         get_client.return_value.get_user_access.assert_called_once_with(
             "ov-example",
             user_id="alice",
+            account_id=None,
         )
 
     def test_list_users_tool_forwards_filters_and_pagination(self):
@@ -215,6 +219,7 @@ def test_list_users_tool_forwards_filters_and_pagination(self):
             role="user",
             page=2,
             limit=10,
+            account_id=None,
         )
 
     def test_register_and_update_tools_match_backend_fields(self):
@@ -232,11 +237,13 @@ def test_register_and_update_tools_match_backend_fields(self):
         get_client.return_value.register_user.assert_called_once_with(
             "ov-example",
             "alice",
+            account_id=None,
         )
         get_client.return_value.update_user.assert_called_once_with(
             "ov-example",
             "alice",
             regenerate_key=True,
+            account_id=None,
         )
 
 
diff --git a/server/mcp_server_openviking_controlplane/uv.lock b/server/mcp_server_openviking_controlplane/uv.lock
index 73f574f2..f9d31aa6 100644
--- a/server/mcp_server_openviking_controlplane/uv.lock
+++ b/server/mcp_server_openviking_controlplane/uv.lock
@@ -468,7 +468,7 @@ cli = [
 
 [[package]]
 name = "mcp-server-openviking-controlplane"
-version = "0.2.0"
+version = "0.3.0"
 source = { editable = "." }
 dependencies = [
     { name = "mcp", extra = ["cli"] },