# CallChatSyn (remote · callchatsyn.com)

Answer small-business customer questions from FAQs, list open appointment times, and book them.

- Trust score: 75/100 (medium)
- Change this week: +4
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-23

## Components

- remote · `callchatsyn.com`: 75/100 (this document), [markdown](https://verifymcp.io/servers/com-callchatsyn-callchatsyn/api-mcp.md), [page](https://verifymcp.io/servers/com-callchatsyn-callchatsyn/api-mcp)

## Channel facts

- Endpoint: `https://callchatsyn.com/api/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.1.0`

## 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 2026-10-23.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (cancel_appointment).
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - 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**: 74/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 822 tokens (~205/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**: 57/100
  - Stability observed for 17 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **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.
- **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 supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

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

CallChatSyn is a hosted endpoint at https://callchatsyn.com/api/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 com-callchatsyn-callchatsyn 'https://callchatsyn.com/api/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "com-callchatsyn-callchatsyn": {
      "url": "https://callchatsyn.com/api/mcp"
    }
  }
}
```

### VS Code

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

### Codex

```toml
[mcp_servers.com-callchatsyn-callchatsyn]
url = "https://callchatsyn.com/api/mcp"
```

### opencode

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

### OpenClaw

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

### Hermes

```yaml
mcp_servers:
  com-callchatsyn-callchatsyn:
    url: "https://callchatsyn.com/api/mcp"
```

### Netclaw

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

### Vellum

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

### Other

```json
{
  "mcpServers": {
    "com-callchatsyn-callchatsyn": {
      "type": "http",
      "url": "https://callchatsyn.com/api/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.

### 2026-10-23 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 53 to 57. That category is still filling its 30-day observation window: 16 days of observed history at the previous scan, 17 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-21 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 47 to 50. That category is still filling its 30-day observation window: 14 days of observed history at the previous scan, 15 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-19 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 40 to 43. That category is still filling its 30-day observation window: 12 days of observed history at the previous scan, 13 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-17 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 33 to 37. That category is still filling its 30-day observation window: 10 days of observed history at the previous scan, 11 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-15 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 27 to 30. That category is still filling its 30-day observation window: 8 days of observed history at the previous scan, 9 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-13 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-12 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 13 to 20. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-10 (score 68, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 13. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (4)

### `answer_customer_question` (~182 tokens)

Answer a customer question

Answer a customer's message for one small business using only that business's own FAQs and order records. Rule-based, not generated, so it never invents prices or opening hours; English and Chinese are detected automatically. Read-only: it never books or changes anything. Use it first for any customer message. If it returns intent 'appointment', call list_open_times next; if matched is false or intent is 'human_handoff', tell the customer a person will follow up. Authenticates with the connection's API key (Authorization: Bearer ccs_live_…); without a key it answers as a public demo business. Returns JSON { intent, lang, matched, reply, next? }.

Input parameters:

- `message` (string, required): The customer's message exactly as they wrote it (1-2,000 characters, English or Chinese). Don't rephrase or translate it.

### `list_open_times` (~158 tokens)

List open appointment times

List the business's next open appointment times: up to 5, soonest first, within the next 7 days, labelled in the business's time zone, plus its services and locations. Read-only. Call it before book_appointment and whenever a customer asks when they can come in. Times come from the business's CallChatSyn hours or from its connected Cal.com calendar. Returns JSON { slots: [{ start, label }], services, locations }; pass a slot's 'start' to book_appointment unchanged. An empty slots list means nothing is open this week.

Input parameters:

- `lang` (string): Language of the human-readable labels: 'en' (default) or 'zh'. Times themselves are always ISO 8601 UTC.

### `book_appointment` (~331 tokens)

Book an appointment

Book one appointment for a customer. This creates a real booking: the business is notified, and if it has connected Cal.com the booking is created there too. With the demo key it's a dry run that books nothing. Not idempotent: booking the same time twice fails the second time. Only call it after the customer has confirmed the time and service; needs a 'start' from list_open_times and the customer's email or phone. Errors: 404 the time is no longer offered (call list_open_times again), 409 it was just taken, 400 missing start, service, or both email and phone, or the business's connected calendar needs a detail the customer didn't give (the message says which, e.g. an email). Returns JSON { booked, id, start, label }; keep 'id' if the customer may want to cancel.

Input parameters:

- `email` (string): The customer's email. Give email or phone (at least one is required).
- `name` (string): The customer's name as they gave it; shown to the business.
- `phone` (string): The customer's phone in international format, e.g. +6591234567. Give email or phone (at least one is required).
- `remarks` (string): Optional note for the business, up to 500 characters (e.g. 'first visit').
- `service` (string, required): What the customer is booking; use one of the 'services' returned by list_open_times.
- `start` (string, required): The exact 'start' value returned by list_open_times (ISO 8601 UTC), unchanged.

### `cancel_appointment` (~151 tokens)

Cancel an appointment

Cancel one of the business's bookings by the 'id' that book_appointment returned. This changes data: the time becomes free again, and if the business has connected Cal.com the booking is cancelled there too (Cal.com emails the customer). Only call it after the customer has clearly asked to cancel that specific booking. To reschedule, cancel and then book a new time from list_open_times. With the demo key it's a dry run. Errors: 404 no such booking for this business, 409 already cancelled, 400 not a booking id. Returns JSON { cancelled, id, start }.

Input parameters:

- `id` (string, required): The booking 'id' returned by book_appointment (a UUID).

## Diagnostics

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

## Score history

- 2026-10-23: 75
- 2026-10-22: 74
- 2026-10-21: 74
- 2026-10-20: 73
- 2026-10-19: 73
- 2026-10-18: 72
- 2026-10-17: 72
- 2026-10-16: 71
- 2026-10-15: 71
- 2026-10-14: 70
- 2026-10-13: 70
- 2026-10-12: 69
- 2026-10-10: 68
- 2026-10-07: 67
- 2026-10-06: 67

## Common questions

### What is the CallChatSyn MCP server?

CallChatSyn is an MCP server listed in the public MCP registry as com.callchatsyn/callchatsyn. Answer small-business customer questions from FAQs, list open appointment times, and book them. This page covers its hosted endpoint (https://callchatsyn.com/api/mcp).

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

CallChatSyn scores 75 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 CallChatSyn MCP server expose?

CallChatSyn exposes 4 tools: answer_customer_question, list_open_times, book_appointment, cancel_appointment. Their descriptions and schemas cost roughly 822 tokens of context every time the server is loaded.

### Does the CallChatSyn MCP server require authentication?

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

### Is the CallChatSyn MCP server still maintained?

CallChatSyn is still listed as active in the MCP registry. We last reached this channel on 23 October 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://callchatsyn.com/api/mcp
- Repository: https://github.com/oneappsworld/callchatsyn-mcp
- Website: https://callchatsyn.com/developers
- Changelog RSS feed: https://verifymcp.io/servers/com-callchatsyn-callchatsyn/api-mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-callchatsyn-callchatsyn/api-mcp.json
- HTML version of this page: https://verifymcp.io/servers/com-callchatsyn-callchatsyn/api-mcp