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Postage Stamp Price MCP server

io.github.theluckystrike/postage-stamp-price-mcptheluckystrikestreamable-httpv1.0.0Scanned

How much is a stamp: USPS Forever stamp, postcard, international and letter postage by weight.

3 tools: 1 change things and 2 only read.

Tools: 0 delete, 0 irreversible, 1 write, 2 read.
  • Reads private data · 2
  • Reads text others write · 3
  • Can send data out · 0
  • No findings

With Anlyon

1 tool here changes things. Govern it.

  • Anlyon lists the tools and adopts none.
  • Each tool you adopt gets approvals and receipts.
  • Your agent never holds the key.
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A tool your agent calls directly is not routed through Anlyon and is not governed by it. anlyon.dev only lists and labels, and these labels are the same either way.

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What the Postage Stamp Price MCP server can do

The Postage Stamp Price MCP server is published by the GitHub account theluckystrike. It has 3 tools. It can create or change data (1 tool: calculate_letter_postage), but cannot delete data. 2 tools only read.

2 tools read private data (get_stamp_price and get_flat_rate_prices); 3 tools bring in text other people can write (get_stamp_price, calculate_letter_postage and get_flat_rate_prices).

None of the fixed checks matched anything in its tool definitions. That is not a safety guarantee.

Last scanned Nov 5, 2026, version 1.0.0.

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

3 tools

Changes things 1Claude Code: ask
  • calculate_letter_postageRetail postage for one letter, postcard or large envelope (flat) by weight, to the US, Canada, Mexico or any other country, with the nonmachinable surcharge for square or rigid car…Reads text others writeNo findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    Description, as the server wrote it
    Retail postage for one letter, postcard or large envelope (flat) by weight, to the US, Canada, Mexico or any other country, with the nonmachinable surcharge for square or rigid cards, the total for a quantity, and the number of Forever stamps per piece. Letters up to 3.5 oz, US large envelopes up to 13 oz.

    Annotations the server declares

    • title: Letter postage
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
Only reads 2Show 2 read-only tools
  • get_flat_rate_pricesCurrent USPS retail prices for Priority Mail Flat Rate envelopes and Small, Medium, Large and APO/FPO/DPO Flat Rate Boxes, and Priority Mail Express Flat Rate envelopes, from Notic…Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "get_flat_rate_prices" says "get": a word for reading.

    What it can reach

    • private-dataThe description's first sentence says "mail": it reads mail.
    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    • untrusted-inputThe description's first sentence says "mail": it reads inbound email, which other people can write.
    Description, as the server wrote it
    Current USPS retail prices for Priority Mail Flat Rate envelopes and Small, Medium, Large and APO/FPO/DPO Flat Rate Boxes, and Priority Mail Express Flat Rate envelopes, from Notice 123.

    Annotations the server declares

    • title: Flat rate prices
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
  • get_stamp_priceThe current USPS Forever stamp price (First-Class Mail 1 oz stamped letter), the 2, 3 and 3.5 oz prices, metered letter prices, postcard, 1 oz large envelope, the nonmachinable sur…Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "get_stamp_price" says "get": a word for reading.

    What it can reach

    • private-dataThe description's first sentence says "mail": it reads mail.
    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    • untrusted-inputThe description's first sentence says "mail": it reads inbound email, which other people can write.
    Description, as the server wrote it
    The current USPS Forever stamp price (First-Class Mail 1 oz stamped letter), the 2, 3 and 3.5 oz prices, metered letter prices, postcard, 1 oz large envelope, the nonmachinable surcharge and the 1 oz international letter (Global Forever) price, read at call time from USPS Notice 123 with its effective date.

    Annotations the server declares

    • title: How much is a stamp
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged outbound.

Reads private data2
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write3
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out0
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Findings

Matches of fixed checks, with the text they matched.

No check matched anything in these tool definitions. That is not a safety guarantee.

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 1.0.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http postage-stamp-price https://postage-stamp-price-mcp.lipmichal.workers.dev/mcp
claude mcp add --transport http postage-stamp-price https://postage-stamp-price-mcp.lipmichal.workers.dev/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__postage-stamp-price__get_stamp_price",
      "mcp__postage-stamp-price__get_flat_rate_prices"
    ],
    "ask": [
      "mcp__postage-stamp-price__calculate_letter_postage"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as postage-stamp-price. Review it before you use it.

Capability tags behind 3 rules
  • mcp__postage-stamp-price__get_stamp_price private-data, untrusted-input
  • mcp__postage-stamp-price__calculate_letter_postage untrusted-input
  • mcp__postage-stamp-price__get_flat_rate_prices private-data, untrusted-input

Pin

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/io.github.theluckystrike/postage-stamp-price-mcp/verify?hash=13e0be2fe2771563e3be85c881a88892b150da8821fd043e4c2a1ec9223dbb22" | jq -e '.changed == false'

Pinned hash 13e0be2fe277, from Nov 5, 2026, 18:18 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/io.github.theluckystrike/postage-stamp-price-mcp/changes.xml

An Atom feed. Works in any feed reader or Slack's RSS app.

Badge

anlyon.dev badge for io.github.theluckystrike/postage-stamp-price-mcp
[![anlyon.dev](https://anlyon.dev/badge/io.github.theluckystrike/postage-stamp-price-mcp.svg)](https://anlyon.dev/servers/io.github.theluckystrike/postage-stamp-price-mcp)

Source: MCP Registry · repository. Synced Nov 5, 2026, 19:17 UTC.

Postage Stamp Price MCP server: questions and answers

Answered from the scan above, not from the publisher's description.

Is the Postage Stamp Price MCP server safe?

No scan can promise that. What its definitions show: 3 tools, 1 of which can change, send or delete something, and 0 findings from fixed checks. Allow the reads, ask before each change, and deny the deletes; the permissions block on this page does that.

Can the Postage Stamp Price MCP server delete data?

No tool is classed as destructive: going by their definitions, none of them deletes, cancels or revokes anything.

Can the Postage Stamp Price MCP server do things that cannot be undone?

No tool is classed as irreversible: none of them sends, pays, publishes or merges, going by their definitions.

What tools does the Postage Stamp Price MCP server have?

3 tools: 1 write, 2 read. calculate_letter_postage, get_stamp_price and get_flat_rate_prices.

Does the Postage Stamp Price MCP server send data to outside services?

None of its tools sends, posts or publishes, or takes a recipient, channel or URL.

Has the Postage Stamp Price MCP server changed its tools?

Not since anlyon.dev started tracking it. Last scanned Nov 5, 2026.