CallChatSyn
REMOTE · CALLCHATSYN.COM
Answer small-business customer questions from FAQs, list open appointment times, and book them.
Available components
Last scanned (17 hours ago)
Scores higher than 69% of remote servers
Reachable. Last reached 23 Oct 2026.
Category CRM and Sales
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. How we score → Why this is hard to score →
Endpoint Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation check failed: no authorisation is required to call this server, and it exposes a tool marked destructive (cancel_appointment). See how to fix → View diagnostics → Fail
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability74
- AI-judged instruction clarity (excellent).Pass
- 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. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management57
- Stability observed for 17 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 23 Oct 26 +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.
- 21 Oct 26 +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.
- 19 Oct 26 +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.
- 17 Oct 26 +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.
- 15 Oct 26 +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.
- 13 Oct 26 +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.
- 12 Oct 26 +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.
- 10 Oct 26 +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.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 23 Oct 2026 · Probed https://callchatsyn.com/api/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=callchatsyn.com | CN=YR1,O=Let's Encrypt,C=US | 17 Oct 2026 | 15 Jan 2027 | RSA 2048 | SHA256-RSA | 51392dcbacdfb9b955d1f64eb0702e3189a |
| SANs: callchatsyn.com | ||||||
| CN=YR1,O=Let's Encrypt,C=US (CA) | CN=Root YR,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | RSA 2048 | SHA256-RSA | a20253f15f2691c05dc1ce13b9bcca4e |
| CN=Root YR,O=ISRG,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | RSA 4096 | SHA256-RSA | f24b6d17f9d9ad7cb1c9fea78782699f |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of callchatsyn.com. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| com. | present | 19718 | 13 | Verified |
| callchatsyn.com. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=63072000 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://callchatsyn.com/api/mcp | Verified | 200 | |
| http (plaintext) | http://callchatsyn.com/api/mcp | HTTPS enforced | 308 | https://callchatsyn.com/api/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
answer_customer_question Answer a customer question ~182
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? }.
| Name | Type | Req | Description |
|---|---|---|---|
| message | string | yes | The customer's message exactly as they wrote it (1-2,000 characters, English or Chinese). Don't rephrase or translate it. |
No output schema declared.
No examples provided.
book_appointment Book an appointment ~331
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.
| Name | Type | Req | Description |
|---|---|---|---|
| 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 | yes | What the customer is booking; use one of the 'services' returned by list_open_times. |
| start | string | yes | The exact 'start' value returned by list_open_times (ISO 8601 UTC), unchanged. |
No output schema declared.
No examples provided.
cancel_appointment Cancel an appointment ~151
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 }.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | The booking 'id' returned by book_appointment (a UUID). |
No output schema declared.
No examples provided.
list_open_times List open appointment times ~158
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.
| Name | Type | Req | Description |
|---|---|---|---|
| lang | string | – | Language of the human-readable labels: 'en' (default) or 'zh'. Times themselves are always ISO 8601 UTC. |
No output schema declared.
No examples provided.
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.
remote · callchatsyn.com
claude mcp add --transport http com-callchatsyn-callchatsyn 'https://callchatsyn.com/api/mcp'
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.