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SMS and WhatsApp Messaging

by hatchloop.dev · remote · no sign-in to list tools · v0.2.13 · published by dev.hatchloop

Send WhatsApp, SMS, email or voice to a business with the compliance gate enforced.

Deletes · 2Changes · 3
CompareRegistry entry

10 tools: 2 can delete or cancel things, 3 change things and 5 only read.

Scanned Oct 21, 2026

No check matched anything in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http sms-whatsapp-messaging https://hatchloop.dev/mcp/sms-whatsapp-messaging

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

10 tools

Deletes or cancels 2Claude Code: deny
  • send_messageSend a message on behalf of an agent's user or an SMB across WhatsApp (free during launch), SMS, email, or voice, sent immediately, no scheduling.Reads text others writeCan send data outNo findings

    Why it is in this group

    • The name "send_message" says "send": a word for sending, and what is sent cannot be taken back.
    • The input addresses people (input.recipient): what it sends cannot be taken back.
    • The server marks it destructive (destructiveHint: true).

    What it can reach

    • untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
    • outboundThe name "send_message" says "send": it sends or publishes something to other people.
    Description, as the server wrote it
    Send a message on behalf of an agent's user or an SMB across WhatsApp (free during launch), SMS, email, or voice, sent immediately, no scheduling. Every send passes a non-bypassable gate: TCPA, GDPR, CASL where modeled, else the service's own opt-in default (the Gulf included). Marketing on SMS, voice, WhatsApp and non-US email without recorded opt-in is rejected (compliance_violation receipt). US marketing email follows CAN-SPAM opt-out rules. [from $0.02/call, variable, not charged while no payment rail is on] [async→get_outcome] [Not available on this deployment: SMS, Voice.]

    Annotations the server declares

    • title: Send Message
    • readOnlyHint: false
    • destructiveHint: true
    • idempotentHint: false
    • openWorldHint: true
  • send_transactional_confirmationIdempotent transactional messages: OTPs, booking confirmations, payment receipts, cancellation notices.Can send data outNo findings

    Why it is in this group

    • The name "send_transactional_confirmation" says "send": a word for sending, and what is sent cannot be taken back.
    • The input addresses people (input.recipient): what it sends cannot be taken back.
    • The server marks it destructive (destructiveHint: true).

    What it can reach

    • outboundThe name "send_transactional_confirmation" says "send": it sends or publishes something to other people.
    Description, as the server wrote it
    Idempotent transactional messages: OTPs, booking confirmations, payment receipts, cancellation notices. Falls back across configured channels; an unconfigured channel fails honestly rather than reporting a delivery that did not happen. [$0.02/per_call, not charged while no payment rail is on] [async→get_outcome] [Not available on this deployment: SMS.]

    Annotations the server declares

    • title: Send Transactional Confirmation
    • readOnlyHint: false
    • destructiveHint: true
    • idempotentHint: false
    • openWorldHint: false
Changes things 3Claude Code: ask
  • check_complianceFree, instant pre-flight for the compliance gate: runs the SAME TCPA/GDPR/CASL/CAN-SPAM/10DLC checks as send_message and call_business, in preview mode -- nothing is sent, nothing …Can send data outNo findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    What it can reach

    • outboundThe input takes a destination (input.channel): what the tool writes goes there.
    Description, as the server wrote it
    Free, instant pre-flight for the compliance gate: runs the SAME TCPA/GDPR/CASL/CAN-SPAM/10DLC checks as send_message and call_business, in preview mode -- nothing is sent, nothing changes. Tells you whether a send would be permitted before you pay, and if not, names the exact rule and how to fix it. De-risks a paid send the way check_booking_link de-risks a paid booking. [free, no key]

    Annotations the server declares

    • title: Check Compliance
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • self_testService health probe: runs 6 internal checks and reports how many passed.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Service health probe: runs 6 internal checks and reports how many passed. Confirms the server is up and responding - it does NOT probe each tool individually. Use to verify connectivity before production use. [free, no key]

    Annotations the server declares

    • title: Self Test
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • verify_businessLook up what we know about a business in our supply network: contact channels, capabilities, last verification.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Look up what we know about a business in our supply network: contact channels, capabilities, last verification. A DIRECTORY LOOKUP - it does not contact the business. Supply-network ids only, not osm:... ids. [free, no key] [limited]

    Annotations the server declares

    • title: Verify Business
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Only reads 5Claude Code: allow
  • find_businessFind real businesses near a place, sorted by distance (nearest of those examined; see result.search).No findings

    Why it is in this group

    • The name "find_business" says "find": a word for reading.
    Description, as the server wrote it
    Find real businesses near a place, sorted by distance (nearest of those examined; see result.search). Data: OpenStreetMap (ODbL, (c) OSM contributors); phone, website, hours only when mapped. Coverage varies; community-mapped, NOT verified by us; source=openstreetmap rows cannot be booked. Answers within about 5 s: status partial (search_in_progress) means repeat the call. If OSM is down: retriable 'temporarily unavailable', never invented rows. [free, no key] [beta]

    Annotations the server declares

    • title: Find Business
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • get_conversationRead a two-way conversation thread you started: its state, every message exchanged, and how many replies the business has sent.Reads private dataReads text others writeNo findings

    Why it is in this group

    • The name "get_conversation" says "get": a word for reading.

    What it can reach

    • private-dataThe name "get_conversation" says "get" and "conversation": it reads messages.
    • private-dataThe description's first sentence says "read" and "conversation": it reads messages.
    • untrusted-inputThe name "get_conversation" says "get" and "conversation": it reads messages, which other people can write.
    • untrusted-inputThe description's first sentence says "read" and "conversation": it reads messages, which other people can write.
    Description, as the server wrote it
    Read a two-way conversation thread you started: its state, every message exchanged, and how many replies the business has sent. [free, requires key]

    Annotations the server declares

    • title: Get Conversation
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
  • get_outcomeRetrieve the final OutcomeReceipt for a completed operation.No findings

    Why it is in this group

    • The name "get_outcome" says "get": a word for reading.
    Description, as the server wrote it
    Retrieve the final OutcomeReceipt for a completed operation. [free, no key]

    Annotations the server declares

    • title: Get Outcome
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • get_statusQuery the current state of any in-flight async operation by operation_id.No findings

    Why it is in this group

    • The name "get_status" says "get": a word for reading.
    Description, as the server wrote it
    Query the current state of any in-flight async operation by operation_id. [free, no key]

    Annotations the server declares

    • title: Get Status
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • preview_costReturn an expected cost estimate, latency estimate, and success-probability estimate for a proposed call before execution.No findings

    Why it is in this group

    • The name "preview_cost" says "preview": a word for reading.
    Description, as the server wrote it
    Return an expected cost estimate, latency estimate, and success-probability estimate for a proposed call before execution. Returns the exact price when it is fixed, and a min/max range when the cost depends on channel or outcome. It does not promise an accuracy percentage - check cost_range. [free, no key]

    Annotations the server declares

    • title: Preview Cost
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

6 paths in this server alone from private data, through text someone else wrote, to a way out. Denying 1 private-data tool breaks every one.

Reads private data1
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write2
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out3
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.
deny to break every path
{
  "permissions": {
    "deny": [
      "mcp__sms-whatsapp-messaging__get_conversation"
    ]
  }
}

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Remote posture

What anyone on the internet sees at the remote endpoint: an anonymous initialize and tools/list, and the public OAuth metadata.

Looked at Oct 22, 2026, 15:18 UTC, unchanged since Oct 22, 2026. No credentials were sent and no tool was called. What is looked at.

Reachable
yes
HTTP status of an anonymous initialize
200
tools/list served without credentials
yes
Tools that change things, listed without credentials
5
Protocol version
2025-06-18
WWW-Authenticate on 401
not observed
resource_metadata in WWW-Authenticate
none
RFC 9728 protected resource metadata
https://hatchloop.dev/.well-known/oauth-protected-resource/mcp/sms-whatsapp-messaging
Authorization servers
https://api.hatchloop.dev
Legacy HTTP+SSE transport
no
Dynamic client registration
yes
Client ID metadata documents
yes
  • HighThe whole server

    The endpoint served tools/list without credentials, and the list has 5 tools that change things (2 destructive, 3 write). Whether a call also works without credentials was not tested: tools are never called.

    Matched text

    https://hatchloop.dev/mcp/sms-whatsapp-messaging: tools/list returned 10 tools to an anonymous client, including send_message (destructive), send_transactional_confirmation (destructive), verify_business (write), self_test (write), check_compliance (write)

    What this check looks for

Install

Pinned to version 0.2.13. Values in angle brackets are yours to fill in.

claude mcp add --transport http sms-whatsapp-messaging https://hatchloop.dev/mcp/sms-whatsapp-messaging

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__sms-whatsapp-messaging__find_business",
      "mcp__sms-whatsapp-messaging__get_status",
      "mcp__sms-whatsapp-messaging__get_outcome",
      "mcp__sms-whatsapp-messaging__preview_cost",
      "mcp__sms-whatsapp-messaging__get_conversation"
    ],
    "ask": [
      "mcp__sms-whatsapp-messaging__verify_business",
      "mcp__sms-whatsapp-messaging__self_test",
      "mcp__sms-whatsapp-messaging__check_compliance"
    ],
    "deny": [
      "mcp__sms-whatsapp-messaging__send_message",
      "mcp__sms-whatsapp-messaging__send_transactional_confirmation"
    ]
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as sms-whatsapp-messaging. Review it before you use it.

Capability tags behind 4 rules
  • mcp__sms-whatsapp-messaging__send_message untrusted-input, outbound
  • mcp__sms-whatsapp-messaging__send_transactional_confirmation outbound
  • mcp__sms-whatsapp-messaging__check_compliance outbound
  • mcp__sms-whatsapp-messaging__get_conversation private-data, untrusted-input