Postbye
com.postbye/postbyepostbye.comstreamable-httpv1.0.0Scanned
Read-only cancellation guides, mailing addresses and letters for thousands of subscriptions.
4 tools: 4 only read.
- Reads private data · 1
- Reads text others write · 1
- Can send data out · 0
- No findings
Anlyon alternative
Run the operations that matter as governed actions.
Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.
Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.
Import an OpenAPI spec →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.
4 tools
Only reads 4Show 4 read-only tools
get_cancellation_guideHow to cancel one company's subscription or membership: how it takes cancellations, the notice period, the traps to check first, billing-partner notes, sources, when the facts were…Reads private dataNo findings
Why it is in this group
- The name "get_cancellation_guide" says "get": a word for reading.
What it can reach
- private-dataThe description's first sentence says "note": it reads notes.
Description, as the server wrote it How to cancel one company's subscription or membership: how it takes cancellations, the notice period, the traps to check first, billing-partner notes, sources, when the facts were verified, the mailing address(es) on file and the guide and address page URLs. Accepts a company slug from search_companies (merged duplicate slugs resolve to the current one).
Annotations the server declares
- title: Get a cancellation guide
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
get_cancellation_letterA plain-text cancellation letter for one company, built from the same template as Postbye's free letter tool, plus where to send it.No findings
Why it is in this group
- The name "get_cancellation_letter" says "get": a word for reading.
Description, as the server wrote it A plain-text cancellation letter for one company, built from the same template as Postbye's free letter tool, plus where to send it. Fields not supplied stay as [bracketed placeholders] to fill in. Nothing is stored.
Annotations the server declares
- title: Get a cancellation letter
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
list_categoriesThe category hubs of the cancellation guides (streaming, gyms, phone and internet, insurance and more) with the number of guides in each and the hub URL.Reads text others writeNo findings
Why it is in this group
- The name "list_categories" says "list": a word for reading.
What it can reach
- untrusted-inputThe description's first sentence says "internet": it reads web pages, which anyone can write.
Description, as the server wrote it The category hubs of the cancellation guides (streaming, gyms, phone and internet, insurance and more) with the number of guides in each and the hub URL.
Annotations the server declares
- title: List guide categories
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
search_companiesFind companies by name (for example "netflix" or "planet fitness") among the subscriptions and memberships Postbye has a cancellation guide for.No findings
Why it is in this group
- The name "search_companies" says "search": a word for reading.
Description, as the server wrote it Find companies by name (for example "netflix" or "planet fitness") among the subscriptions and memberships Postbye has a cancellation guide for. Returns each match's slug, category, how the company takes cancellations and the guide URL. Use the slug with get_cancellation_guide.
Annotations the server declares
- title: Search cancellation guides
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: false
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 data1
- Reads files, mail, messages, databases, secrets, calendars or repositories.
- Reads text others write1
- 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.
Install
Pinned to version 1.0.0. Values in angle brackets are yours to fill in.
claude mcp add --transport http postbye https://postbye.com/mcpclaude mcp add --transport http postbye https://postbye.com/mcpRun 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.
{
"permissions": {
"allow": [
"mcp__postbye__search_companies",
"mcp__postbye__get_cancellation_guide",
"mcp__postbye__get_cancellation_letter",
"mcp__postbye__list_categories"
],
"ask": [],
"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 postbye. Review it before you use it.
Capability tags behind 2 rules
- mcp__postbye__get_cancellation_guide private-data
- mcp__postbye__list_categories 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/com.postbye/postbye/verify?hash=83033acc5da7d129e904cfa93dab0b933e276bc70b053ddadf4af2ab83e4f187" | jq -e '.changed == false'Pinned hash 83033acc5da7, from Oct 27, 2026, 05:17 UTC.
Watch
Get told when its tools change: a new tool, a new description, a new class.
https://anlyon.dev/servers/com.postbye/postbye/changes.xmlAn Atom feed. Works in any feed reader or Slack's RSS app.
Badge
[](https://anlyon.dev/servers/com.postbye/postbye)Source: MCP Registry. Synced Oct 27, 2026, 05:17 UTC.