I Bond Rate MCP

io.github.theluckystrike由 GitHub 帳號 theluckystrike 發布v1.0.0更新於 Nov 5, 2026

Current I bond rate, what your I bond earns by issue month, and value estimates from TreasuryDirect.

已驗證Streamable HTTP可網頁執行金融資料與分析

概覽

AI 產生的概覽

遠端 MCP 伺服器，讓助理查詢 TreasuryDirect 的美國 I 系列儲蓄債券目前利率、依購買月份計算的個別債券利率，以及估值。

可以做什麼
  • 查詢目前 I 債券的綜合利率、固定利率與半年通膨率，以及發行期間和下次公布日期
  • 依購買月份取得某張債券的固定利率、目前 6 個月計息利率、利率調整月份與完整利率區間
  • 依購買月份與金額估算債券價值，以及持有未滿 5 年扣除 3 個月利息後的贖回價值
  • 用財政部綜合利率公式，對假設的固定利率與通膨率進行預測計算
  • 取得自 1998 年 9 月以來每次公布的固定利率、半年通膨率與綜合利率
適用情境
適合回答現在 I 債券利率是多少、某月買進的既有債券目前賺多少、某筆持有值多少以及贖回可拿多少這類問題。也適合做假設性利率試算，因為目前利率晚於多數模型的訓練資料。
執行需求
需要一個遠端 streamable HTTP 端點，不需 API 金鑰、權杖或註冊。README 另提到本機 npm 方式，但該套件尚未發布，屆時需 Node 20 或更新版本。需要能連線到託管端點，取得即時利率時還需連線到 TreasuryDirect。
安裝前請注意
唯讀：不會存取你的 TreasuryDirect 帳戶，也不處理 EE 債券或稅務。估值是以每 25 美元面額、半年複利計算的估計值，可能與財政部數值相差幾美分。個別債券利率表使用內建利率表，託管伺服器在 TreasuryDirect 沒有回應時會改用該表，結果可能落後於即時頁面；每次結果都會標明所用來源。

安裝

在 SourceWeft 中

  1. 開啟 儀表板中的 I Bond Rate MCP，將其新增到工作區。
  2. 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/io.github.theluckystrike%2Fi-bond-rate-mcp/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": {
    "i-bond-rate": {
      "type": "http",
      "url": "https://i-bond-rate-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

README

i-bond-rate-mcp

Current I bond rate for AI assistants, and the rate your own I bond earns now. I bonds bought from November 1, 2026 to April 30, 2027 earn 5.51 percent, with a 1.40 percent fixed rate.

This is a Model Context Protocol (MCP) server. It reads the current rate from TreasuryDirect at call time and carries every rate since September 1998 from the TreasuryDirect rate chart. It needs no API key.

Tools

ToolWhat it returns
get_current_i_bond_rateComposite, fixed and semiannual inflation rate for I bonds bought now, the issue window, the next announcement date and the purchase and redemption rules.
get_i_bond_rate_for_issue_dateFor a bond bought in a given month: its fixed rate, the rate it earns in the current 6-month period, the two months its rate changes, whether it can be cashed and every rate period since issue.
estimate_i_bond_valueEstimated value for an issue month and amount, with all interest and after the 3-month penalty for bonds under 5 years.
calculate_i_bond_composite_rateThe Treasury formula for any fixed rate and semiannual inflation rate, for predictions.
get_i_bond_rate_historyEvery fixed rate and semiannual inflation rate since September 1998, newest first.

Every result has structured JSON, a one-paragraph summary, as_of, source (the TreasuryDirect page or rate chart) and more (a page on mcpstamp.com).

What it knows that your model does not

  • The November 2026 rates (5.51 percent composite, 1.40 percent fixed, 2.04 percent semiannual inflation). Treasury announced them on November 1, 2026.
  • That an existing bond does not earn the new-bond rate. It keeps its own fixed rate and gets a new inflation rate every 6 months from its issue month, so a bond bought in April 2022 earns 3.34 percent from October 2026 while a bond bought in January 2023 earns 3.75 percent until January 2027.
  • The exact rounding and the zero floor. The formula reproduces all 1,711 composite rates in the Treasury chart.

Install

Hosted (Claude.ai custom connector, ChatGPT developer mode)

Paste this URL. No token, no sign-up. It works now.

https://i-bond-rate-mcp.lipmichal.workers.dev/mcp

Claude Code

claude mcp add --transport http i-bond https://i-bond-rate-mcp.lipmichal.workers.dev/mcp

Claude Desktop

Claude Desktop adds remote servers under Settings, Connectors, Add custom connector. Paste the URL above.

Cursor

Add to ~/.cursor/mcp.json:

json
{  "mcpServers": {    "i-bond": { "url": "https://i-bond-rate-mcp.lipmichal.workers.dev/mcp" }  }}

VS Code

Add to .vscode/mcp.json:

json
{  "servers": {    "i-bond": { "type": "http", "url": "https://i-bond-rate-mcp.lipmichal.workers.dev/mcp" }  }}

Local stdio (after npm release)

The npm package is not published yet. After it is, run it locally with Node 20 or newer:

claude mcp add i-bond -- npx -y i-bond-rate-mcp

Example prompts

  • "What is the I bond rate right now?"
  • "What is the I bond fixed rate for November 2026?"
  • "I bought I bonds in April 2022. What rate are they earning now?"
  • "What is $10,000 of I bonds bought in January 2023 worth today, and what would I get if I cash them?"
  • "If May 2027 inflation is 1.5 percent and the fixed rate stays at 1.40, what would the I bond rate be?"

Data sources

Full list with fetch dates in DATA_SOURCES.md.

Limitations

  • Value is an estimate per $25 with semiannual compounding. Treasury values can differ by cents. Your TreasuryDirect account and the Savings Bond Calculator are the record.
  • Rates after April 2027 are not known until Treasury announces them on May 1, 2027. The current-rate tool reads the live page, but the per-bond schedule uses the built-in chart until this server is updated.
  • TreasuryDirect did not answer the hosted Worker on 2026-11-05, so the hosted server falls back to the built-in rate chart after a few seconds. Every result says which source it used in rate_source.
  • It does not read your TreasuryDirect account and does not handle EE bonds or taxes.

More

More MCP servers that answer questions your assistant cannot answer alone are on mcpstamp.com.

Part of the Zovo MCP collection: https://mcp.zovo.one

Built by theluckystrike.

Development

npm installnpm test                              # builds, then runs the fixture tests and an offline stdio testnode scripts/stdio-transcript.mjs     # live stdio round trip, writes .live/stdio-transcript.jsonl

License

MIT

來源：README.md，提交 c73af2b

工具

5

get_current_i_bond_rate

Get current I bond rate

Current Series I savings bond composite rate, fixed rate and semiannual inflation rate for new purchases, read at call time from the TreasuryDirect "I bonds interest rates" page with the built-in rate chart as fallback. November 2026 to April 2027: 5.51 percent with a 1.40 percent fixed rate. Also returns the next announcement date and the $10,000 limit, 12-month hold and 3-month penalty rules.

無需輸入參數。

get_i_bond_rate_for_issue_date

Get I bond rate for an issue date

For an I bond bought in a given month: its fixed rate, the composite rate it earns in the current (or given) 6-month period, the months its rate changes, whether it can be cashed and the penalty, and every rate period since issue. Computed from the TreasuryDirect rate chart effective November 1, 2026.

輸入參數as_of_monthissue_month必填

estimate_i_bond_value

Estimate I bond value

Estimate what I bonds are worth for an issue month and purchase amount at the start of a month: value with all interest and the redemption value after the 3-month penalty for bonds under 5 years. Uses semiannual compounding per $25 with the TreasuryDirect rates. An estimate; Treasury values can differ by cents.

輸入參數amount必填as_of_monthissue_month必填

calculate_i_bond_composite_rate

Calculate I bond composite rate

Apply the Treasury formula fixed + 2 x semiannual inflation + fixed x semiannual inflation, rounded to 0.01 percent with a floor of zero. Use it for rate predictions.

輸入參數fixed_rate必填semiannual_inflation_rate必填

get_i_bond_rate_history

Get I bond rate history

Fixed rate for new bonds, semiannual inflation rate and composite rate for every May and November announcement since September 1998, newest first, from the TreasuryDirect rate chart.

輸入參數limit

版本歷史

1
  1. v1.0.0最新Nov 5, 2026

評分

已滿足適用檢查項的 100%

該評分衡量此收錄條目的完整程度，依據註冊中心條目、端點與公開來源計算得出。它不是對伺服器本身的評價，也不表示伺服器安全或目前可用：可連通性是帶日期的檢查結果，評分也不包含安裝量或使用者評價。

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  • 已宣告認證方式必需10 分
  • 已列出工具必需15 分
  • 描述必需15 分
  • 圖示10 分
  • 文件15 分
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