Check Digits

dev.toolstopv0.2.2更新於 Nov 2, 2026

Catch a mistyped barcode, ISBN, VIN, NPI or LEI before a bad identifier corrupts a record.

發布方自己的服務：check.tattoo: tattoo size and placement guide

已驗證Streamable HTTP可網頁執行金融開發者工具

概覽

AI 產生的概覽

一個無狀態的遠端 MCP 伺服器，用來驗證 IBAN、ISBN、GTIN/UPC/EAN 條碼、VIN、NPI、ISIN、路由號與信用卡號等識別碼的檢查碼。

可以做什麼: 驗證 IBAN、LEI、ISIN、ABA 路由號等金融識別碼的檢查碼
驗證 GTIN/UPC/EAN 條碼、ISBN 等商品與出版品編碼
驗證 VIN、NPI、信用卡號等其他結構化識別碼
僅依呼叫參數作答，不保存狀態，也不查詢上游服務
適用情境: 適合助理處理含識別碼的資料時使用，在寫入紀錄前找出打錯或格式錯誤的條碼、ISBN、VIN、NPI、LEI 或帳號。
執行需求: 需要一個遠端 streamable HTTP 端點；不需安裝、帳號、API 金鑰或環境變數。README 另提到可用 npx 在本機以 stdio 執行，但同時說明託管端點已停止服務、npm 套件已棄用。

安裝前請注意

README 說明託管端點已於 2026 年 9 月下線、npm 套件已棄用，依賴前應先確認可用性。請求會帶有真實識別碼（如 IBAN 與卡號）；README 稱遙測只記錄呼叫類型與結果，以及由截斷並雜湊後的網路位址衍生的工作階段 ID。

安裝

在 SourceWeft 中

開啟儀表板中的 Check Digits，將其新增到工作區。
為需要使用其工具的對話啟用該服務。

Web executable，透過 Streamable HTTP。遠端服務在工作區中設定後即可從網頁執行環境執行。

交給代理程式安裝

把這段提示詞貼上到 Claude Code、Codex、Cursor 等代理程式，或 SourceWeft 對話中。代理程式會讀取該伺服器的安裝指南，先向你展示發布者、端點和登入方式，經你同意後再把它新增到你的客戶端。金鑰不會寫進任何命令。

閱讀 https://sourceweft.com/mcp/dev.toolstop%2Fcheck-digits/install.md，並按其中說明把這個 MCP 伺服器接入我的客戶端。修改任何設定之前，先告訴我它的發布者、端點和登入方式，等我確認。不要把 API 金鑰寫進命令或我會提交的檔案；問我金鑰應從哪裡取得。

檢視代理程式所依據的安裝指南

其他 MCP 客戶端

把它新增到你客戶端的 mcpServers 設定中。

{
  "mcpServers": {
    "check-digits": {
      "type": "http",
      "url": "https://check-digits.toolstop.dev/"
    }
  }
}

README

toolstop

Small, stateless MCP servers. Each one does a single narrow job exactly, so an assistant can call it instead of guessing.

Every server runs on Cloudflare Workers at <name>.toolstop.dev, holds no state, and can also run locally over stdio.

Discontinued September 2026. The hosted endpoints are gone and the npm packages are deprecated. The code still runs locally over stdio if you want it; the export-control tables are frozen at their 2026-08-27 edition.

Servers

Connecting

Remote, over streamable HTTP. No install, no account:

json

{  "mcpServers": {    "check-digits": {      "type": "url",      "url": "https://check-digits.toolstop.dev"    }  }}

{  "mcpServers": {    "check-digits": {      "type": "url",      "url": "https://check-digits.toolstop.dev"    }  }}

Local, over stdio:

Design

Stateless. No database, no vector index, no metered upstream API. A request is answered from its arguments alone. Servers scale to zero and an idle one costs nothing.

Zero runtime dependencies. No MCP SDK, no schema library. MCP over streamable HTTP is request/response, which makes hand-rolled dispatch small enough to be worth it: faster cold starts, and no supply chain.

Telemetry records shape and outcome, never argument values. A check-digit server that logged its input would be storing real IBANs and card numbers. The transport emits one row per request describing what kind of call happened and whether it succeeded. packages/_shared/transport.test.mjs asserts that no raw argument value can reach it.

The row also carries a session id, and it is derived from the network the request came from, truncated to a /24 or /48 before hashing, never the full address. Hashing the whole IP would not have anonymised it: the IPv4 space is 32 bits and the other inputs are public, so the id was walkable back to one address until this was fixed on 2026-08-10. Each server's README states the complete recorded row rather than only what is left out.

Every tool declares readOnlyHint, a complete inputSchema and an outputSchema, so a client can tell what a call will do before making it and what shape comes back. The transport refuses to start a server whose tools do not state their annotations, rather than defaulting them to something reassuring.

Repo layout

packages/_shared/     shared transport, dispatch and telemetrypackages/mcp-<name>/  one serverscripts/discover.mjs  derives the CI matrix from the filesystemscripts/smoke.mjs     protocol check against a live endpoint

packages/_shared/     shared transport, dispatch and telemetrypackages/mcp-<name>/  one serverscripts/discover.mjs  derives the CI matrix from the filesystemscripts/smoke.mjs     protocol check against a live endpoint

See CLAUDE.md for the operating manual.

Development

bash

npm installnpm test                                # every server plus the shared transportnode scripts/smoke.mjs mcp-check-digits # protocol check against the live endpoint

npm installnpm test                                # every server plus the shared transportnode scripts/smoke.mjs mcp-check-digits # protocol check against the live endpoint