# Courio (remote · api.courio.si)

Mail real paper letters (standard, registered, registered with receipt) worldwide. No account.

- Trust score: 69/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `api.courio.si`: 69/100 (this document), [markdown](https://verifymcp.io/servers/si-courio-courio/api.md), [page](https://verifymcp.io/servers/si-courio-courio/api)

## Channel facts

- Endpoint: `https://api.courio.si/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.0`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 77/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC is configured correctly; the domain's records validate against the full chain to the root.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 63/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 867 tokens (~216/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 7/100
  - Stability observed for 2 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 73/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 20% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the Courio MCP server?

Courio is a hosted endpoint at https://api.courio.si/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http si-courio-courio 'https://api.courio.si/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "si-courio-courio": {
      "url": "https://api.courio.si/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "si-courio-courio": {
      "type": "http",
      "url": "https://api.courio.si/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.si-courio-courio]
url = "https://api.courio.si/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "si-courio-courio": {
      "type": "remote",
      "url": "https://api.courio.si/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add si-courio-courio --url 'https://api.courio.si/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  si-courio-courio:
    url: "https://api.courio.si/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "si-courio-courio": {
      "Transport": "http",
      "Url": "https://api.courio.si/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add si-courio-courio -t streamable-http -u 'https://api.courio.si/mcp'
```

### Other

```json
{
  "mcpServers": {
    "si-courio-courio": {
      "type": "http",
      "url": "https://api.courio.si/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-05 (score 69, 0)

- [security] Tool “get_coverage” rewrote its description, which is the text the model reads
- [security] Tool “quote_letter” rewrote its description, which is the text the model reads
- [security] Tool “send_letter” rewrote its description, which is the text the model reads

### 2026-11-04 (score 69, +2)

- [security improvement] DNSSEC: fail → pass
- [functional improvement] Stability: unverified → 0.03

### 2026-11-03 (score 67)

First indexed and scored.

## MCP tools (4)

### `get_coverage` (~181 tokens)

Check coverage and indicative prices

Lists which destination countries and service levels Courio can mail a physical paper letter to, with an indicative "from" price (EUR including VAT, 1 black-and-white page), typical delivery time and the legal product name. No account or API key is needed. Call it before quote_letter to check a destination is served; pass a country (ISO 3166-1 alpha-2, e.g. "DE") to narrow the answer. Service levels: "standard" (ordinary mail, no proof), "tracked" (tracking only), "registered" (registered mail: proof of deposit), "registered_ar" (registered with acknowledgement of receipt: proof of delivery, the one to use for legal notices).

Input parameters:

- `country` (string): ISO 3166-1 alpha-2 code, e.g. "DE"; omit for every country

### `quote_letter` (~282 tokens)

Get a free quote for a letter

Prices a physical letter (printed, enveloped and posted by Courio) and returns a quote_id. Free and commits to nothing: no account, no payment, nothing is mailed. Give the service level, sender and recipient postal addresses, and the document (pdf_base64, pdf_url, or plain/markdown text). The price is in EUR including VAT (set currency to "USD" to also see a USD price), fixed for 24 hours. The document is checked and content-moderated; a problem comes back as an error with a hint. Quotes are capped per day (limit_exceeded with retry_after): reuse a quote_id rather than re-quoting. Service levels: "standard" (ordinary mail, no proof), "tracked" (tracking only), "registered" (registered mail: proof of deposit), "registered_ar" (registered with acknowledgement of receipt: proof of delivery, the one to use for legal notices). The quote gives the estimated delivery time (estimated_delivery_days). Next step: show the price, the legal product and the terms of sale (terms_url) to the human, then call send_letter if they agree.

Input parameters:

- `currency` (string)
- `document` (required)
- `options` (object)
- `recipient` (object, required)
- `sender` (object, required)
- `service` (string, required)

### `send_letter` (~304 tokens)

Create the letter and get the payment link

Creates the letter for a quote and returns a payment link (Stripe Checkout). No account is needed. YOU CANNOT PAY: show the price and the payment link to the human and ask them to open it and pay. The letter is mailed right after payment and cannot be cancelled or recalled once paid, so paying is the point of no return: make sure the human has seen the price, the recipient and the document first. Calling it again with the same quote_id returns the same letter and link (or its current status once it has been paid). The link expires after about 24 hours. Optionally pass webhook_url (public https) to be notified of status changes. Poll get_letter_status to follow the letter. Autonomous agents whose owner gave them a card through a Stripe Shared Payment Token (e.g. Link) can pay by card themselves with MPP through the REST API (POST /v1/letters with payment_method "mpp", which may be disabled: 422 payment_method_unavailable). Agents that can sign crypto payments can instead pay with x402 through the REST API (POST /v1/letters with payment_method "x402", which may be disabled on this deployment: 422 payment_method_unavailable); official x402 clients cap a payment at $1 by default, so raise the spend limit to cover the quoted price first.

Input parameters:

- `quote_id` (string, required)
- `webhook_url` (string): Public https URL notified on each status change

### `get_letter_status` (~100 tokens)

Follow a letter

Returns the current status of a letter (awaiting_payment, paid, submitted, in_transit, delivered, failed, expired, ...), its timeline and, once available, proof links (proof of deposit for "registered", proof of delivery for "registered_ar"). No account is needed; the letter_id is the credential. Recipient details are partially redacted unless the request carries the API key that created the letter.

Input parameters:

- `letter_id` (string, required)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/si-courio-courio/api#diagnostics

## Score history

- 2026-11-05: 69
- 2026-11-04: 69
- 2026-11-03: 67

## Common questions

### What is the Courio MCP server?

Courio is an MCP server listed in the public MCP registry as si.courio/courio. Mail real paper letters (standard, registered, registered with receipt) worldwide. No account. This page covers its hosted endpoint (https://api.courio.si/mcp).

### Is the Courio MCP server safe to use?

Courio scores 69 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the Courio MCP server expose?

Courio exposes 4 tools: get_coverage, quote_letter, send_letter, get_letter_status. Their descriptions and schemas cost roughly 867 tokens of context every time the server is loaded.

### Does the Courio MCP server require authentication?

No. We connected to Courio without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the Courio MCP server still maintained?

Courio is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://api.courio.si/mcp
- Website: https://courio.si/agents
- Changelog RSS feed: https://verifymcp.io/servers/si-courio-courio/api.xml
- Changelog JSON feed: https://verifymcp.io/servers/si-courio-courio/api.json
- HTML version of this page: https://verifymcp.io/servers/si-courio-courio/api