Send16 MCP server

• Registry namecom.send16/send16verified in the MCP registry

The registry name sits under send16.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-29
• Tools87
• Server calls itselfsend16
• Server version0.5.16
• Protocol version2025-06-18

On 2026-10-29 the server answered initialize and tools/list without a sign-in. First answer in 486 ms.

• Checked on 4 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 4 so far
• Answeredmeasuring4 of the 7 daily checks it takes to print a share
• Median first answer495 ms
• Sign-inOAuth: the client signs you inclients register themselves: claude.ai and ChatGPT connect with nothing set up first

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• whoami

  Verify the API key and return the authenticated workspace: name, plan, email quota (used/limit), and owner. Call this first to confirm the key works before sending. Pair with list_domains to see which `from` addresses are allowed.

• send_email

  Send a transactional email through Send16. Provide `html`, `text`, or both (text-only is fine for OTPs/receipts/alerts). `from_email` must belong to a domain that is verified in the workspace; call `whoami` for the account and…

• send_campaign_test

  Send a test email for an existing campaign to preview how it will look in recipients' inboxes. Confirm the test address with the user first. Can be refused with 403 SENDING_PAUSED (workspace under review, nothing was sent, tell the user…

• create_campaign

  Create a new email campaign as a draft: optionally with full HTML content and recipients (exactly ONE of audienceIds / segmentId / contactIds / tagIds / sendToAll) so it's ready to test and send. Nothing is sent until schedule_campaign.

• design_email_template

  Use AI to generate a complete email HTML template based on a description. Returns ready-to-use HTML that can be sent or used in campaigns.

• list_campaigns

  List email campaigns, newest first. Use `search` to find a past campaign the user describes vaguely ('the invite one', 'that July newsletter'); it matches name and subject case-insensitively; try distinctive words from their description…

• create_contact

  Add a single new contact, optionally straight into audiences and/or with tags; e.g. 'add this person from my email into the newsletter list'. Contacts are subscribed by default. For more than a handful of people, use import_contacts…

• search_contacts

  Search contacts by email address or name. Returns matching contacts with their tags and subscription status.

• list_contacts

  List all contacts with optional filtering by subscription status and tag. Supports pagination.

• import_contacts

  Bulk import contacts from CSV data (min column: email), optionally straight into audiences and/or with tags. This is the tool for cross-app flows; e.g. pulling people out of Gmail, a CRM, or a spreadsheet and landing them in a Send16…

• list_domains

  List all sending domains configured in your Send16 workspace, including their verification status and DNS records.

• check_domain_health

  Check the DNS health of a specific domain, including DKIM, SPF, DMARC, and MX record verification status. Triggers a fresh DNS lookup.

• get_campaign_stats

  Get detailed performance statistics for a specific campaign including open rate, click rate, bounce rate, and delivery metrics.

• get_deliverability_status

  Get your workspace's deliverability summary: sending reputation, domain authentication status, and recent bounce/complaint health. (Deliverability Hub plan feature.)

• list_automations

  List all automations in the workspace, including draft/active/paused status and trigger types.

• get_automation

  Get a single automation by ID, including its trigger, steps, and current status.

• enroll_in_automation

  Manually enroll a contact in an active automation. The automation must be in 'active' status. Use send_event for event-driven enrollment. Confirm with the user first: the automation can start emailing the contact straight away.

• send_event

  Fire a custom event for a contact. Automations whose trigger is `{type:'custom_event', eventName:'<name>'}` will enroll the contact and start running. Payload is exposed to condition steps as `event.<key>`. Confirm with the user first if…

• list_templates

  List starter-gallery email templates available to every workspace.

• save_template

  Save an email design as a reusable template in the user's Send16 workspace. Use this when the user has designed an email (for example in a Claude artifact) and wants it in Send16. Pass the complete email HTML. Send16 hosts every image…

• list_workspace_templates

  List the templates saved in the user's own Send16 workspace (their template library, including ones saved with save_template). For the shared starter gallery use list_templates.

• send_template_test

  Send a preview of a saved workspace template to one email address, so the user can see it in a real inbox. It arrives from [email protected] with a small 'Template test preview' banner and uses sample merge values (first name 'Test')…

• get_template

  Get a single starter template by ID, including its EmailContent JSON.

• render_email_content

  Compile an EmailContent JSON object (the shape used by the Send16 builder + templates) into HTML using the platform's authoritative renderer. Returns the exact HTML the API would send. Useful for previews and post-processing.

• add_domain

  Register a new sending domain. Returns the DNS records the user must add to their DNS provider, after which they should call check_domain_health to verify.

• pre_send_review

  Run an AI pre-send review on an email's HTML before sending. Surfaces tone issues, broken links, missing alt text, spam triggers, and accessibility problems.

• generate_email_from_url

  Scrape a URL (e.g. a launch blog post or product page) and generate an email draft from its content. Returns subject, preview text, and HTML body.

• list_messages

  List messages from the unified send log (transactional + campaign). Filter by recipient, sender, status, date range, or source.

• get_message

  Fetch a single message with its full event timeline (created → sent → delivered → opened → clicked → ...).

• get_message_events

  Get just the delivery event timeline for a message: no body or recipient details.

• list_convos

  List inbox conversations. Filter by state, mailbox, label, screener status, or full-text search. Send16's unified inbox combines transactional reply threading with team-managed shared inboxes.

• get_convo

  Get a single conversation with its full thread of posts (incoming + outgoing).

• send_reply

  Reply to an inbox conversation. The reply is sent from the original recipient address (the alias the convo arrived on) and threaded back to the contact. Show the user the reply text and get a clear yes first: it goes to a real person and…

• mark_convo_read

  Mark a conversation as read for the current viewer.

• update_convo

  Update conversation status (open/closed/archived/snoozed) or assignee.

• add_convo_note

  Add a private internal note on a conversation. Notes are visible only to workspace members.

• screener_decide

  Decide a pending screener conversation (first-time sender). 'allow' lets future emails through, 'reject' blocks, 'cold' marks as cold outreach.

• list_inbox_counts

  Get unread/total counts per category and label for the inbox sidebar (newsletter, transactional, marketing, calendar, social, cold).

• list_topics

  List subscription topics. Topics are granular categories contacts can subscribe to (e.g. 'product-updates', 'weekly-digest'). Campaigns and automations can be gated to subscribers of a specific topic.

• create_topic

  Create a new subscription topic. Contacts opt into topics individually via the preference center.

• update_topic

  Update a subscription topic (name, description, default).

• delete_topic

  Delete a subscription topic. All subscribers will be detached.

• list_actions

  List Actions. Actions fire a transactional template when a custom event arrives: simple 'event_name → template' pairings, lighter than full automations.

• get_action

  Get a single Action with its trigger config and template binding.

• create_action

  Create an Action that maps an event name to a transactional template. Each matching event sends one email to the contact.

• update_action

  Update an Action (toggle enabled, change template, change event name).

• delete_action

  Delete an Action.

• list_audiences

  List audiences (lists). An audience is a static, manually-managed group of contacts.

• create_audience

  Create a new audience.

• add_contacts_to_audience

  Add contacts (by ID) to an audience.

• remove_contact_from_audience

  Remove a contact from an audience.

• delete_audience

  Delete an audience (list). Contacts are not deleted; only the list and its memberships are removed.

• list_segments

  List dynamic segments. Segments compute their members from a filter expression at send time.

• preview_segment

  Preview the contacts that match a segment without sending.

• list_events

  List the workspace's events (meetups, workshops, conferences) with registered, attended and no-show counts and each event's public registration page.

• get_event_insights

  Who registered and who came for one event: counts, no-show rate, where people came from (city and state), first-timers vs returning, organisations and registrations over time. Without an eventId, returns insights across every event…

• list_event_registrations

  List the people registered for an event, with status (registered, waitlisted, attended, no_show, cancelled), company, city and check-in time.

• register_for_event

  Register someone for an event. They get the event's confirmation email with their QR ticket unless the organiser switched it off, so confirm the person and the event with the user first. Registering doesn't subscribe them to marketing…

• check_in_attendee

  Check a registrant in at the door (or undo it). Use the registration ID from list_event_registrations.

• update_contact

  Update a contact's profile fields, custom fields, or subscription state.

The first 60 of 87, as the server listed them.