Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@CallChatSyn MCP Server Do you have any open appointments this week, and can you book one for me?"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Let an AI assistant (Claude, Cursor, any MCP client) answer customer questions and book appointments for a small business, using that business's own FAQs and opening hours on CallChatSyn.
Free for the first 1,000 businesses (founder offer: 100 API calls a day, 2,000 a month).
Tool | Changes data? | What it does |
| No (read-only) | Answers from the business's FAQs and order data (English/Chinese); flags booking and "talk to a person" requests |
| No (read-only) | Next open times (up to 5, next 7 days) in the business's time zone, plus services and locations; from CallChatSyn hours or the business's connected Cal.com |
| Yes, creates a booking | Books one of those times and returns its |
| Yes, cancels a booking | Cancels a booking by |
Related MCP server: Main Street MCP
Add this URL as a custom connector (Claude: Settings → Connectors → Add custom connector; Cursor and others: a Streamable HTTP server):
https://callchatsyn.com/api/mcpWithout a key it uses the demo business. To act for your own business, send the header Authorization: Bearer ccs_live_.... Also listed in the official MCP Registry as com.callchatsyn/callchatsyn.
Create a CallChatSyn account, add FAQs and opening hours, then Dashboard → Developers → claim founder access → create an API key.
Add to your MCP client config:
{
"mcpServers": {
"callchatsyn": {
"command": "npx",
"args": ["-y", "github:oneappsworld/callchatsyn-mcp"],
"env": { "CALLCHATSYN_API_KEY": "ccs_live_..." }
}
}
}Keep the key private; it acts for one business.
No key yet? Leave CALLCHATSYN_API_KEY out and the server uses the public demo key (ccs_demo_public): answers come from a demo business and bookings are dry runs, so you can try every tool before signing up.
Answers are rule-based FAQ matching (fast, predictable), not free-form generation.
API docs and OpenAPI spec: https://callchatsyn.com/developers · https://callchatsyn.com/openapi.json
MIT licensed.
Answer a customer's message using the business's own FAQs and order data (English or Chinese). Returns intent (faq, order_status, appointment, human_handoff), the reply, and matched=false when no FAQ fit.
Inputs: message (required).
Book one of the open times from list_open_times. Needs the exact 'start' value, a service, and the customer's email or phone. Confirm details with the customer before calling.
Inputs: start (required), service (required), name, email, +2 more.
List the next open appointment times (labels in the business's time zone), plus its services and locations.
Inputs: lang.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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Scored across 3 tools
The three tools have distinct core purposes: answering informational queries, listing available times, and booking appointments. However, answer_customer_question returns an 'appointment' intent that might tempt an agent to use it for scheduling queries instead of list_open_times, creating a mild boundary overlap.
All tool names use snake_case and follow a verb-first pattern (answer_customer_question, list_open_times, book_appointment). The convention is consistent and predictable.
Three tools are well-scoped for a focused customer chat and appointment booking server; each tool serves a clear, non-redundant role and the set avoids bloat.
The surface covers answering FAQs/orders and booking appointments, but lacks tools for canceling or rescheduling appointments and for actually performing a human handoff. These are notable gaps for a customer service lifecycle.
Run a local business from your AI app: bookings, customers, inbox, website, posts and payments.
Verified local businesses, bookable by AI agents: services, prices, availability and appointments.
Run a service business from your AI agent: CRM, leads, scheduling, invoicing, jobs and more.
AI phone agents for service businesses: answer calls, book appointments and win back customers.
