io.github.spruikco/send16-mcp

REMOTE · MCP.SEND16.COM · 2 COMPONENTS · SCANNED AUG 3

Email for AI agents: send mail, manage contacts, automations & webhooks. Zero-DNS first send.

Available components

remote · mcp.send16.com 75 npm · send16-mcp 65

+7 this week 75 75 Trust /100

Trust breakdown (6 categories)

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 →

Endpoint Security77

The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
Authorisation is enforced on tool calls, but the challenge carries no valid RFC 9728 metadata, so a client cannot discover where to get a token. See how to fix → View diagnostics → Fail
HTTPS not yet verified: we couldn't determine whether a plaintext access path exists. View diagnostics → Unverified
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 Usability77

AI-judged instruction clarity (excellent).Pass
Tool/resource definitions use about 6917 tokens (~87/item across 79 items; 79 tools + 0 resources), lean.Pass
Usage-examples check failed: none of the tools include examples. See how to fix → Fail

Stability & Change Management27

Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial

Tool Coverage96

100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
87% of tool parameters carry a description.Partial

Capabilities100

Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass

Install

Add this component to your MCP client. Where a client-specific snippet is available, pick your client below and copy it straight into your config; otherwise use the connection detail shown.

remote · mcp.send16.com

Claude Codex opencode OpenClaw Hermes Other

# add to Claude Code

claude mcp add --transport http spruikco-send16-mcp https://mcp.send16.com/mcp

# ~/.codex/config.toml

[mcp_servers.spruikco-send16-mcp]
url = "https://mcp.send16.com/mcp"

// opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "spruikco-send16-mcp": {
      "type": "remote",
      "url": "https://mcp.send16.com/mcp",
      "enabled": true
    }
  }
}

# add to OpenClaw

openclaw mcp add spruikco-send16-mcp --url https://mcp.send16.com/mcp --transport streamable-http

# ~/.hermes/config.yaml

mcp_servers:
  spruikco-send16-mcp:
    url: "https://mcp.send16.com/mcp"

// mcp.json

{
  "mcpServers": {
    "spruikco-send16-mcp": {
      "type": "http",
      "url": "https://mcp.send16.com/mcp"
    }
  }
}

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

Changelog Show cosmetic changes

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.

3 Aug 26 +1

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.
2 Aug 26 +1
- Tool “list_campaigns” rewrote its description, which is the text the model reads security
- Tool “update_campaign” rewrote its description, which is the text the model reads security
- Tool “create_campaign” rewrote its description, which is the text the model reads security
- Tool “create_contact” rewrote its description, which is the text the model reads security
- Tool “duplicate_campaign” rewrote its description, which is the text the model reads security
- Tool “import_contacts” rewrote its description, which is the text the model reads security
- Tool “update_convo” rewrote its description, which is the text the model reads security
- Schema quality: 79 → 87 ▼ functional
- Schema quality: good → excellent functional
- Server version: 0.5.8 → 0.5.13 functional
- “list_automation_enrollments” added an optional parameter “pageSize” cosmetic
- “list_campaigns” added an optional parameter “search” cosmetic
- “update_campaign” added an optional parameter “audienceIds” cosmetic
- “update_campaign” added an optional parameter “contactIds” cosmetic
- “update_campaign” added an optional parameter “name” cosmetic
- “update_campaign” added an optional parameter “segmentId” cosmetic
- “update_campaign” added an optional parameter “tagIds” cosmetic
- “create_campaign” added an optional parameter “audienceIds” cosmetic
- “create_campaign” added an optional parameter “contactIds” cosmetic
- “create_campaign” added an optional parameter “html” cosmetic
- “create_campaign” added an optional parameter “segmentId” cosmetic
- “create_campaign” added an optional parameter “sendToAll” cosmetic
- “create_campaign” added an optional parameter “tagIds” cosmetic
- “create_contact” added an optional parameter “audienceIds” cosmetic
- “duplicate_campaign” added an optional parameter “audienceIds” cosmetic
- “duplicate_campaign” added an optional parameter “contactIds” cosmetic
- “duplicate_campaign” added an optional parameter “name” cosmetic
- “duplicate_campaign” added an optional parameter “segmentId” cosmetic
- “duplicate_campaign” added an optional parameter “sendToAll” cosmetic
- “duplicate_campaign” added an optional parameter “tagIds” cosmetic
- “import_contacts” added an optional parameter “audienceIds” cosmetic
- “update_campaign” added an optional parameter “sendToAll” cosmetic
- “list_automation_enrollments” added an optional parameter “page” cosmetic
- “list_convos” reworded the description of “label” cosmetic
- “list_convos” reworded the description of “state” cosmetic
- “update_brand” reworded the description of “fontFamily” cosmetic
- “update_convo” reworded the description of “assigneeId” cosmetic
- “update_convo” reworded the description of “state” cosmetic
- “create_contact” reworded the description of “tags” cosmetic
- “duplicate_campaign” reworded the description of “campaignId” cosmetic
- “import_contacts” reworded the description of “csvData” cosmetic
- “import_contacts” reworded the description of “tags” cosmetic
- “list_convos” dropped the optional parameter “offset” cosmetic
- “list_convos” dropped the optional parameter “screener_status” cosmetic
- “update_campaign” dropped the optional parameter “templateSlug” cosmetic
- “update_convo” dropped the optional parameter “starred” cosmetic
- “list_automation_enrollments” dropped the optional parameter “cursor” cosmetic
- “list_automation_enrollments” dropped the optional parameter “limit” cosmetic
31 Jul 26 +3
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
30 Jul 26 +1
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
28 Jul 26 +1

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.
27 Jul 26 +1
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
26 Jul 26 67

First indexed and scored.

Show 5 earlier entries Hide earlier entries

Diagnostics

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 3 Aug 2026 · Probed https://mcp.send16.com/mcp

TLS valid

Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .

Subject	Issuer	Valid from	Valid until	Key	Signature	Serial
CN=*.send16.com	CN=E8,O=Let's Encrypt,C=US	25 May 2026	23 Aug 2026	ECDSA 256	ECDSA-SHA384	5c623be2f8a0f4533b7ea9199adf5acbfcf
SANs: *.send16.com
CN=E8,O=Let's Encrypt,C=US (CA)	CN=ISRG Root X1,O=Internet Security Research Group,C=US	13 Mar 2024	12 Mar 2027	ECDSA 384	SHA256-RSA	63959363c24e7082715918bfc3d7ed56

DNSSEC insecure

Validation of mcp.send16.com. — Not signed

Zone	DS	Keys	Algorithms	Outcome
.	trust_anchor	20326, 38696	8, 8	Verified
com.	present	19718	13	Verified
send16.com.	absent			Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation

Authentication Challenged, unverified

The endpoint asked for a token, but we could not retrieve and validate the RFC 9728 metadata that tells a client how to obtain one.

Result	Challenged, unverified
Enforced	On tool calls
HTTP status	200

Header	Value
strict-transport-security	max-age=63072000; includeSubDomains; preload
x-content-type-options	nosniff
x-frame-options	DENY
referrer-policy	strict-origin-when-cross-origin

Protected resource metadata

Retrieved	No
Problem	no_resource_metadata

Transports 2 probes

Transport	URL	Outcome	Status	Location
streamable-http	https://mcp.send16.com/mcp	Verified	200
http (plaintext)	http://mcp.send16.com/mcp	Inconclusive	404

MCP tools — 79 exposed · ~6,917 tokens

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.

Tool Tokens

list_topics ~70

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.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)

No output schema declared.

No examples provided.

list_webhooks ~56

List configured outgoing webhooks (your endpoints that Send16 POSTs delivery events to). Outgoing webhooks are a plan feature.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)

No output schema declared.

No examples provided.

list_workspaces ~44

List workspaces the authenticated user has access to (owner or member).

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)

No output schema declared.

No examples provided.

mark_convo_read ~51

Mark a conversation as read for the current viewer.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
convoId	string	yes	Conversation ID

No output schema declared.

No examples provided.

pause_automation ~56

Pause an automation. Existing enrollments freeze in place; no new contacts enroll.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
automationId	string	yes	Automation ID

No output schema declared.

No examples provided.

pause_campaign ~55

Pause a sending campaign. Already-sent messages are unaffected; remaining sends halt.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
campaignId	string	yes	Campaign ID

No output schema declared.

No examples provided.

pre_send_review ~101

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.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
audience	string	—	Short description of the audience (helps tone analysis)
html	string	yes	Full HTML body to review
subject	string	yes	Email subject line

No output schema declared.

No examples provided.

preview_campaign_recipients ~58

Preview the recipient set for a campaign before sending. Returns count + sample list.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
campaignId	string	yes	Campaign ID

No output schema declared.

No examples provided.

preview_segment ~49

Preview the contacts that match a segment without sending.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
segmentId	string	yes	Segment ID

No output schema declared.

No examples provided.

regenerate_webhook_secret ~60

Rotate the HMAC signing secret for an outgoing webhook endpoint. Returns the new secret once.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
webhookId	string	yes	Webhook ID

No output schema declared.

No examples provided.

remove_contact_from_audience ~59

Remove a contact from an audience.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
audienceId	string	yes	Audience ID
contactId	string	yes	Contact ID

No output schema declared.

No examples provided.

remove_suppression ~59

Remove an email from the suppression list. Use only when you've confirmed the recipient wants to receive mail again.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
email	string	yes	—

No output schema declared.

No examples provided.

render_email_content ~108

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.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
content	object	yes	EmailContent JSON (from get_template or the builder)
variables	object	—	Variable replacements (e.g. {firstName:'Alice'})

No output schema declared.

No examples provided.

resume_campaign ~44

Resume a paused campaign.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
campaignId	string	yes	Campaign ID

No output schema declared.

No examples provided.

schedule_campaign ~99

Schedule (or send immediately) an existing draft campaign to an audience/segment/topic.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
audienceId	string	—	—
campaignId	string	yes	Campaign ID
scheduleAt	string	—	ISO-8601 future datetime; omit to send immediately
segmentId	string	—	—
topicId	string	—	—

No output schema declared.

No examples provided.

screener_decide ~83

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

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
convoId	string	yes	Conversation ID
decision	string	yes	Screener decision

No output schema declared.

No examples provided.

search_contacts ~90

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

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
page	integer	—	Page number
pageSize	integer	—	Results per page (max 100)
query	string	yes	Search query (matches against email, first name, last name)

No output schema declared.

No examples provided.

send_broadcast ~220

One-shot broadcast: create a campaign and immediately schedule it to send, in a single call. Pass either an audienceId, segmentId, topicId, or fully-qualified filter. Provide html OR templateSlug.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
audienceId	string	—	Send to all contacts in this audience
fromEmail	string	yes	Must be a verified domain
fromName	string	yes	—
html	string	—	Full HTML body (one of html/templateSlug required)
name	string	yes	Internal campaign name
previewText	string	—	—
replyTo	string	—	—
scheduleAt	string	—	ISO-8601 future datetime; omit to send immediately
segmentId	string	—	Send to all contacts matching this segment
subject	string	yes	—
templateSlug	string	—	Workspace template slug to use
topicId	string	—	Send to all subscribers of this topic

No output schema declared.

No examples provided.

send_campaign_test ~79

Send a test email for an existing campaign to preview how it will look in recipients' inboxes.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
campaignId	string	yes	Campaign ID to send test for
testEmail	string	yes	Email address to send the test to

No output schema declared.

No examples provided.

send_email ~275

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 `list_domains` to see which senders are allowed; a send from an unverified domain returns a clear error, not a silent failure. For a zero-setup first send, use from_email `[email protected]` — the sandbox sender delivers with no DNS, but only to your own account email.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
from_email	string	—	Sender email address (must be from a verified domain)
from_name	string	—	Sender display name (e.g. "Acme Co")
html	string	—	HTML body content
reply_to	string	—	Reply-to email address
subject	string	yes	Email subject line
template	string	—	Transactional template slug to use instead of inline content
text	string	—	Plain text body content
to	—	yes	Recipient email address or array of addresses (max 50)
variables	object	—	Template variables for merge tags

No output schema declared.

No examples provided.

send_event ~163

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>`.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
contactEmail	string	—	Contact email (provide either this or contactId)
contactId	string	—	Contact UUID (provide either this or contactEmail)
name	string	yes	Event name (e.g. 'trial_started', 'order.placed')
occurredAt	string	—	ISO-8601 timestamp; defaults to now
payload	object	—	Arbitrary JSON metadata available to automation conditions

No output schema declared.

No examples provided.

send_reply ~94

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.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
convoId	string	yes	Conversation ID
html	string	—	HTML body of the reply
text	string	—	Plain text body of the reply

No output schema declared.

No examples provided.

update_action ~99

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

Input Output Examples

Name	Type	Req	Description
actionId	string	yes	Action ID
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
delaySeconds	integer	—	—
enabled	boolean	—	—
eventName	string	—	—
name	string	—	—
sendOnce	boolean	—	—
templateSlug	string	—	—

No output schema declared.

No examples provided.

update_brand ~131

Update workspace brand settings. The designSpec field is a Markdown DESIGN.md document fed into AI generation system prompts — use it to encode voice, do/don't lists, and visual rules.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
designSpec	string	—	Markdown DESIGN.md spec for AI generation
fontFamily	string	—	Body font family
logoUrl	string	—	—
primaryColor	string	—	Hex color (e.g. '#4F46E5')
secondaryColor	string	—	Hex color

No output schema declared.

No examples provided.

update_campaign ~250

Update a draft campaign: name, subject, preview text, sender info, HTML content, and/or recipients. Retarget with exactly ONE of audienceIds / segmentId / contactIds / tagIds / sendToAll, then verify with preview_campaign_recipients before sending. Only drafts can be edited.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
audienceIds	array	—	Retarget to these audience IDs (see list_audiences). Sets recipient type 'lists'.
campaignId	string	yes	Campaign ID
contactIds	array	—	Retarget to these specific contact IDs
fromEmail	string	—	—
fromName	string	—	—
html	string	—	—
name	string	—	Campaign name (internal label)
previewText	string	—	—
replyTo	string	—	—
segmentId	string	—	Retarget to this segment (see list_segments)
sendToAll	boolean	—	Retarget to all subscribed contacts in the workspace
subject	string	—	—
tagIds	array	—	Retarget to contacts with these tag IDs

No output schema declared.

No examples provided.

update_contact ~84

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

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
contactId	string	yes	Contact ID
customFields	object	—	—
firstName	string	—	—
lastName	string	—	—
subscribed	boolean	—	—

No output schema declared.

No examples provided.

update_convo ~85

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

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
assigneeId	—	—	Workspace member user ID, or null to unassign
convoId	string	yes	Conversation ID
state	string	—	New status

No output schema declared.

No examples provided.

update_topic ~72

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

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)
description	string	—	—
isDefault	boolean	—	—
name	string	—	—
topicId	string	yes	Topic ID

No output schema declared.

No examples provided.

whoami ~78

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.

Input Output Examples

Name	Type	Req	Description
apiKey	string	—	Send16 API key (overrides SEND16_API_KEY env var)

No output schema declared.

No examples provided.

On this page

Handy links

Scoring key

80+ high trust
60–79 medium
below 60 low

How we score

Score history · last 30 days

26 Jul 3 Aug

Day	Score
26 Jul	67
27 Jul	68
28 Jul	69
29 Jul	69
30 Jul	70
31 Jul	73
1 Aug	73
2 Aug	74
3 Aug	75