# 1820.ch – Telefonbuch Schweiz

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

- name: ch.1820/telefonbuch
- version: 1.0.1
- connection class: R0 (autonomous)
- trust: 82/100 flags: no-repository
- quality: 79/100 (good)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/ch.1820%2Ftelefonbuch
- tools: https://api.protogrid.dev/v1/servers/ch.1820%2Ftelefonbuch/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

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


## Trust

- hygiene: 80
- liveness: 99
- freshness: 100
- provenance: 55
- drivers: +dns-namespace +website +reachable +uptime-97% +updated-23d-ago -no-repository
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 79/100 (good)

### protocol: 88 (weight 25)

- pass `protocol.modern`: supports 2026-07-28 (server/discover)
- pass `protocol.stateless`: answers without a session
- pass `protocol.transport`: streamable HTTP
- warn `protocol.list_ttl`: tools/list declares ttlMs 0, so clients re-fetch it on every use

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 86 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- pass `tools.annotations`: 4 of 4 tools declare readOnlyHint or destructiveHint
- fail `tools.directory_hints`: no tool declares all four of readOnlyHint, destructiveHint, idempotentHint and openWorldHint; missing: reverse_phone_lookup (destructiveHint, openWorldHint); browse_business_category (destructiveHint, openWorldHint); get_directory_entry (destructiveHint, openWorldHint); …
- pass `tools.token_cost`: about 999 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: 50 (weight 15)

- pass `stability.changes`: 4 tool changes in 30 days
- fail `stability.rug_pull`: 1 tools kept their name but changed most of their description in 30 days; review before trusting them

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 4, about 999 tokens to load them all
- tool set hash: 66000dfc412ba9e2511f45f0bd54af02
- tools last changed: 2026-09-27T22:47:57.516Z
- badge: [![protogrid quality](https://protogrid.dev/badge/ch.1820/telefonbuch.svg)](https://protogrid.dev/servers/ch.1820/telefonbuch)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

- 2026-09-27 `search_swiss_directory` changed (description, inputSchema, annotations) **meaning changed**
  - before: Full-text search over the Swiss public phone/business directory (1820.ch): matches on name, company, or category, optionally narrowed by locality/postcode/canton. Use get_directory_entry for phone numbers and opening hours of a specific result.
  - after: 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.
- 2026-09-27 `reverse_phone_lookup` changed (inputSchema, annotations)
- 2026-09-27 `get_directory_entry` changed (inputSchema, annotations)
- 2026-09-27 `browse_business_category` changed (inputSchema, annotations)

Full history: https://api.protogrid.dev/v1/servers/ch.1820%2Ftelefonbuch/changes

## Remotes

- https://mcp.1820.ch/mcp (streamable-http, auth none, reachable true, uptime30d 0.96629214)

## Packages

_none_

## Tools (4)

- `browse_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.
- `get_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.
- `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.
- `search_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.