# Postbye MCP server

> For AI agents: a plain-text index of this site is at https://postbye.com/llms.txt

Ask your AI assistant how to cancel a subscription and get the answer from Postbye's guides: how the company takes cancellations, the notice period, the traps to check, the mailing address on file and a ready-to-send letter.

- **Read-only**: The four tools only look things up. Nothing is changed, bought or sent, and nothing you type is stored.
- **No sign-in needed**: The server is public: there is no account, key or token to set up. Clients that insist on OAuth can take an optional read-only token (see Install).
- **Same as the site**: Every answer is built from the same data as the company's page on postbye.com, so the two always agree.

## Endpoint

One URL, the MCP Streamable HTTP transport, JSON responses:

```
https://postbye.com/mcp
```

The server keeps no sessions, so any client can call it at any time. A browser visit or a GET request returns a short description (HTTP 405) because /mcp only accepts POST. Cross-origin calls from web clients are allowed.

## Connect your assistant

Pick the client you use. All of them need only the endpoint above.

### Claude and Claude Desktop

On claude.ai, Claude Desktop or the mobile app, open Settings, then Connectors, and choose Add custom connector. Enter Postbye as the name and the endpoint as the URL, then save. Leave the sign-in fields empty.

```
https://postbye.com/mcp
```

### Claude Code

Run this once in your terminal:

```
claude mcp add --transport http postbye https://postbye.com/mcp
```

### Cursor

Add the server to .cursor/mcp.json in your project, or to ~/.cursor/mcp.json for every project:

```json
{
  "mcpServers": {
    "postbye": {
      "url": "https://postbye.com/mcp"
    }
  }
}
```

### VS Code

Add the server to .vscode/mcp.json in your workspace (GitHub Copilot agent mode reads it):

```json
{
  "servers": {
    "postbye": {
      "type": "http",
      "url": "https://postbye.com/mcp"
    }
  }
}
```

### ChatGPT (developer mode)

In ChatGPT, open Settings, then Connectors, then Advanced, and turn on Developer mode. Create a new connector, enter Postbye as the name and the endpoint as the MCP server URL, and set authentication to none.

```
https://postbye.com/mcp
```

## The four tools

All four are marked read-only and closed-world. The examples below are the server's real answers, shortened.

### search_companies

Finds a company by name and returns its slug, category, how it takes cancellations and the guide URL. Up to 10 matches.

Inputs: query (text), limit (1 to 10, optional). Ask your assistant: "Which subscription is Netflix, and how do I cancel it?"

**Example call**

```json
{
  "name": "search_companies",
  "arguments": {
    "query": "netflix",
    "limit": 1
  }
}
```

**Answer (shortened)**

```
1 match for "netflix":
1. Netflix (slug: netflix), Streaming & entertainment. Online. https://postbye.com/cancel/netflix
All guides: https://postbye.com/cancel
Postbye can mail this letter by certified mail: https://postbye.com/how-it-works
```

### get_cancellation_guide

The full guide for one company: how it takes cancellations, notice period, traps, billing-partner notes, sources, the date the facts were verified and every mailing address on file. Slugs of merged duplicates resolve to the current company.

Inputs: slug (text). Ask your assistant: "What do I need to check before cancelling Netflix?"

**Example call**

```json
{
  "name": "get_cancellation_guide",
  "arguments": {
    "slug": "netflix"
  }
}
```

**Answer (shortened)**

```
How to cancel Netflix (Streaming & entertainment)
Slug: netflix. Accepts cancellations: Online.

Directly with Netflix, the way to cancel is: Online. Notice rule: Cancel anytime; access continues to the end of the paid billing period.

Notice period: Cancel anytime; access continues to the end of the paid billing period

...
```

### get_cancellation_letter

A plain-text cancellation letter from the same template as the free letter tool, with the address to send it to. Anything you do not supply stays as a [bracketed] placeholder.

Inputs: slug (text), customer_name (optional), account_number (optional). Ask your assistant: "Write a cancellation letter for my Netflix account."

**Example call**

```json
{
  "name": "get_cancellation_letter",
  "arguments": {
    "slug": "netflix",
    "customer_name": "Alex Example"
  }
}
```

**Answer (shortened)**

```
Alex Example
[Your street address]
[City, state and ZIP code]
[Your email address]

[Today’s date]

...
```

### list_categories

The guide categories (streaming, gyms, phone and internet, insurance and more) with the number of guides in each and the category URL.

Inputs: none. Ask your assistant: "Which kinds of subscriptions does Postbye cover?"

**Example call**

```json
{
  "name": "list_categories",
  "arguments": {}
}
```

**Answer (shortened)**

```
30 categories of cancellation guides:
- News & magazines (884 guides, 71 verified by hand): https://postbye.com/cancel/category/news-magazines
- Insurance & protection plans (732 guides, 31 verified by hand): https://postbye.com/cancel/category/insurance
- Software & apps (653 guides, 314 verified by hand): https://postbye.com/cancel/category/software
- Phone & internet (467 guides, 66 verified by hand): https://postbye.com/cancel/category/telecom
- Streaming & entertainment (446 guides, 156 verified by hand): https://postbye.com/cancel/category/streaming
- Finance & credit (438 guides, 57 verified by hand): https://postbye.com/cancel/category/finance
...
```

## Documentation

Five pages go deeper than this overview:

- [Install the Postbye MCP Server](https://postbye.com/mcp-server/install): Set-up for Claude, Claude Code, Cursor, VS Code and ChatGPT, and how access works.
- [Postbye MCP Tools Reference](https://postbye.com/mcp-server/tools): Inputs, limits and results of the four tools.
- [Postbye MCP Examples](https://postbye.com/mcp-server/examples): Example prompts, tool calls with the server's real answers, and a curl request.
- [Postbye MCP Server FAQ](https://postbye.com/mcp-server/faq): Access, cost, data, limits and how the server relates to postbye.com.
- [Connect the Postbye MCP Server](https://postbye.com/mcp-server/clients): Steps and configuration for Claude, Cursor, VS Code, ChatGPT, the OpenAI API and other clients.

## Discovery files

For directories and clients that look for MCP servers on their own:

- [Server card](https://postbye.com/.well-known/mcp/server-card.json): Name, version, endpoint and protocol versions as JSON.
- [mcp.json](https://postbye.com/.well-known/mcp.json): The same identity plus the endpoint, transport and the four tools.
- [OpenAPI spec](https://postbye.com/openapi.json): OpenAPI 3.1 description of the public read-only API: GET /api/v1/companies/{slug} and the MCP endpoint.
- [A2A agent card](https://postbye.com/.well-known/agent.json): Agent card with the company-lookup skills and links to the OpenAPI spec and the MCP endpoint.
- [OAuth server metadata](https://postbye.com/.well-known/oauth-authorization-server): Optional OAuth 2.1 sign-in for clients that need a token: endpoints, grants and PKCE.
- [OAuth protected-resource metadata](https://postbye.com/.well-known/oauth-protected-resource): Names the MCP endpoint as the protected resource and its authorization server.
- [Official MCP Registry entry](https://registry.modelcontextprotocol.io/v0/servers?search=com.postbye/postbye): Listed as com.postbye/postbye, verified for the postbye.com domain.
- [Source and README on GitHub](https://github.com/postbye-team/postbye-mcp): The server.json published to the registry, setup notes and licence.
- [llms.txt](https://postbye.com/llms.txt): Plain-text map of the site for AI assistants.

Official MCP Registry name: com.postbye/postbye.

## Want the letter mailed for you?

Postbye prints the letter, sends it by certified mail and emails you the signed delivery proof.

[Find your company](https://postbye.com/cancel)