# 1820.ch – Telefonbuch Schweiz (remote · mcp.1820.ch)

Swiss phone directory: search people and businesses, reverse number lookup, business categories.

- Trust score: 85/100 (high trust)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-07

## Components

- remote · `mcp.1820.ch`: 85/100 (this document), [markdown](https://verifymcp.io/servers/ch-1820-telefonbuch/mcp.md), [page](https://verifymcp.io/servers/ch-1820-telefonbuch/mcp)

## Channel facts

- Endpoint: `https://mcp.1820.ch/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.1`

## 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 2026-11-07.

- **Endpoint Security**: 74/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Nothing on it is marked destructive, but we can't show that an anonymous caller can only read: full credit needs the server to list at least one tool and every tool to be verifiably read-only. We use a best-effort check of tool names and descriptions to tell read-only tools from tools that change things, so some genuinely read-only tools may not get full credit. Names that start with a read verb (get, list, read, search and similar) and accurate readOnlyHint annotations help. Meet that to earn full credit, or require authorisation.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 75/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 660 tokens (~165/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**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - 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 current MCP spec version (2026-07-28).

## Install

### How do I install the 1820.ch – Telefonbuch Schweiz MCP server?

1820.ch – Telefonbuch Schweiz is a hosted endpoint at https://mcp.1820.ch/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 ch-1820-telefonbuch 'https://mcp.1820.ch/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "ch-1820-telefonbuch": {
      "url": "https://mcp.1820.ch/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "ch-1820-telefonbuch": {
      "type": "http",
      "url": "https://mcp.1820.ch/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.ch-1820-telefonbuch]
url = "https://mcp.1820.ch/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "ch-1820-telefonbuch": {
      "type": "remote",
      "url": "https://mcp.1820.ch/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add ch-1820-telefonbuch --url 'https://mcp.1820.ch/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  ch-1820-telefonbuch:
    url: "https://mcp.1820.ch/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "ch-1820-telefonbuch": {
      "Transport": "http",
      "Url": "https://mcp.1820.ch/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add ch-1820-telefonbuch -t streamable-http -u 'https://mcp.1820.ch/mcp'
```

### Other

```json
{
  "mcpServers": {
    "ch-1820-telefonbuch": {
      "type": "http",
      "url": "https://mcp.1820.ch/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.

### 2026-11-06 (score 85, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-10-27 (score 85, 0)

- [security] Stability: 0.97 → pass

### 2026-10-26 (score 85, +1)

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-24 (score 84, +1)

No change was recorded against any check on this day. Stability & Change Management went from 87 to 90. That category is still filling its 30-day observation window: 26 days of observed history at the previous scan, 27 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-22 (score 83, +1)

No change was recorded against any check on this day. Stability & Change Management went from 80 to 83. That category is still filling its 30-day observation window: 24 days of observed history at the previous scan, 25 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-20 (score 82, +1)

No change was recorded against any check on this day. Stability & Change Management went from 73 to 77. That category is still filling its 30-day observation window: 22 days of observed history at the previous scan, 23 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-18 (score 81, +1)

No change was recorded against any check on this day. Stability & Change Management went from 67 to 70. That category is still filling its 30-day observation window: 20 days of observed history at the previous scan, 21 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-15 (score 80, +1)

No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (4)

### `browse_business_category` (~176 tokens)

Browse a business category

Lists public directory entries in one business category, optionally narrowed to a locality/postcode/canton. Use search_swiss_directory instead for a free-text query.

Input parameters:

- `category` (string, required): The business category slug (e.g. "restaurant", "coiffeur", "sanitaer"). Valid slugs are the slug values in categories, as returned by get_directory_entry, or a top-level group slug such as "bau-handw…
- `lang` (string): Response language: de, fr, it, or en. Defaults to de.
- `limit` (integer): Maximum number of results, 1-20.
- `location` (string): Locality, postcode, or canton (e.g. "Baden", "5400", "ZH") to narrow the category to. Always put a place name here.

Output parameters:

- `advertising_block_note` (string)
- `results` (null|array)
- `retrieved_at` (string)
- `source` (object)

### `get_directory_entry` (~121 tokens)

Get a directory entry

Fetches the full public detail for one directory entry by its entry_id (public_id), including phone numbers, opening hours, and links when the entry has them. Use get_directory_entry for phone numbers and opening hours; use search_swiss_directory or browse_business_category to find an entry_id first.

Input parameters:

- `entry_id` (string, required): The entry's public_id, as returned by search_swiss_directory, browse_business_category, or reverse_phone_lookup.
- `lang` (string): Response language: de, fr, it, or en. Defaults to de.

Output parameters:

- `advertising_block_note` (string)
- `entry` (object)
- `retrieved_at` (string)
- `source` (object)

### `reverse_phone_lookup` (~118 tokens)

Reverse phone lookup

Looks up the public directory entry (or entries) associated with a Swiss phone number. Accepts national ("079 123 45 67"), E.164 ("+41791234567"), or compact notation. Returns an empty result list when the number has no findable public listing.

Input parameters:

- `lang` (string): Response language: de, fr, it, or en. Defaults to de.
- `phone_number` (string, required): The phone number to look up, in any common Swiss notation (national, E.164, or compact).

Output parameters:

- `results` (null|array)
- `retrieved_at` (string)
- `source` (object)

### `search_swiss_directory` (~245 tokens)

Search the Swiss directory

Full-text search over the Swiss public phone/business directory (1820.ch). Matches ALL words in query, so a short keyword works best; put any place name in location, not query. For "business type X in place Y", browse_business_category with a category slug is an alternative. Use get_directory_entry for phone numbers and opening hours of a specific result.

Input parameters:

- `entry_type` (string): Restrict results to person, business, or all entries.
- `lang` (string): Response language: de, fr, it, or en. Defaults to de.
- `limit` (integer): Maximum number of results, 1-20.
- `location` (string): Locality, postcode, or canton (e.g. "Baden", "5400", "ZH") to narrow the search. Always put a place name here, never in query.
- `query` (string, required): One short keyword: a person's or company name, or ONE business type (e.g. "Müller", "Migros", "Coiffeur"). Every word must match, so no sentences or extra adjectives. Never put a place name here — us…

Output parameters:

- `advertising_block_note` (string)
- `results` (null|array)
- `retrieved_at` (string)
- `source` (object)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/ch-1820-telefonbuch/mcp#diagnostics

## Score history

- 2026-11-07: 85
- 2026-11-06: 85
- 2026-11-05: 85
- 2026-11-04: 85
- 2026-11-03: 85
- 2026-11-02: 85
- 2026-11-01: 85
- 2026-10-31: 85
- 2026-10-30: 85
- 2026-10-29: 85
- 2026-10-28: 85
- 2026-10-27: 85
- 2026-10-26: 85
- 2026-10-25: 84
- 2026-10-24: 84
- 2026-10-23: 83
- 2026-10-22: 83
- 2026-10-21: 82
- 2026-10-20: 82
- 2026-10-19: 81
- 2026-10-18: 81
- 2026-10-17: 80
- 2026-10-16: 80
- 2026-10-15: 80
- 2026-10-14: 79
- 2026-10-13: 79
- 2026-10-12: 78
- 2026-10-10: 77
- 2026-10-09: 77
- 2026-10-06: 75

## Common questions

### What is the 1820.ch – Telefonbuch Schweiz MCP server?

1820.ch – Telefonbuch Schweiz is an MCP server listed in the public MCP registry as ch.1820/telefonbuch. Swiss phone directory: search people and businesses, reverse number lookup, business categories. This page covers its hosted endpoint (https://mcp.1820.ch/mcp).

### Is the 1820.ch – Telefonbuch Schweiz MCP server safe to use?

1820.ch – Telefonbuch Schweiz scores 85 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 1820.ch – Telefonbuch Schweiz MCP server expose?

1820.ch – Telefonbuch Schweiz exposes 4 tools: browse_business_category, get_directory_entry, reverse_phone_lookup, search_swiss_directory. Their descriptions and schemas cost roughly 660 tokens of context every time the server is loaded.

### Does the 1820.ch – Telefonbuch Schweiz MCP server require authentication?

No. We connected to 1820.ch – Telefonbuch Schweiz without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the 1820.ch – Telefonbuch Schweiz MCP server still maintained?

1820.ch – Telefonbuch Schweiz is still listed as active in the MCP registry. We last reached this channel on 7 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What did VerifyMCP test on the 1820.ch – Telefonbuch Schweiz MCP server?

VerifyMCP ran 13 checks on 1820.ch – Telefonbuch Schweiz, covering TLS certificate, Authorization, HTTPS, HSTS header and 9 more. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.

## Links

- Remote endpoint: https://mcp.1820.ch/mcp
- Website: https://1820.ch/ch/de/ki-assistenten
- Changelog RSS feed: https://verifymcp.io/servers/ch-1820-telefonbuch/mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/ch-1820-telefonbuch/mcp/changelog.json
- Trust report (JSON): https://verifymcp.io/servers/ch-1820-telefonbuch/mcp.json
- HTML version of this page: https://verifymcp.io/servers/ch-1820-telefonbuch/mcp