docs: add Sequenzy integration (#312)

Co-authored-by: Nic <nic@sequenzy.com>

tools/REGISTRY.md

@@ -47,6 +47,7 @@ Quick reference for AI agents to discover tool capabilities and integration meth
 | customer-io | Email | ✓ | - | [✓](clis/customer-io.js) | ✓ | [customer-io.md](integrations/customer-io.md) |
 | sendgrid | Email | ✓ | - | [✓](clis/sendgrid.js) | ✓ | [sendgrid.md](integrations/sendgrid.md) |
 | resend | Email | ✓ | ✓ | [✓](clis/resend.js) | ✓ | [resend.md](integrations/resend.md) |
+| sequenzy | Email | ✓ | ✓ | ✓ | - | [sequenzy.md](integrations/sequenzy.md) |
 | nitrosend | Email | ✓ | ✓ | - | - | [nitrosend.md](integrations/nitrosend.md) |
 | kit | Email | ✓ | - | [✓](clis/kit.js) | ✓ | [kit.md](integrations/kit.md) |
 | beehiiv | Newsletter | ✓ | - | [✓](clis/beehiiv.js) | - | [beehiiv.md](integrations/beehiiv.md) |
@@ -185,6 +186,7 @@ Email marketing, transactional email, and automation platforms.
 | **customer-io** | Behavior-based messaging | - |
 | **sendgrid** | Transactional email at scale | - |
 | **resend** | Developer-friendly transactional | ✓ |
+| **sequenzy** | Lifecycle email, sequences, transactional email | ✓ |
 | **kit** | Creator/newsletter focused | - |
 | **beehiiv** | Newsletter platform | - |
 | **klaviyo** | E-commerce email + SMS | - |
@@ -192,7 +194,7 @@ Email marketing, transactional email, and automation platforms.
 | **brevo** | Email + SMS, popular in EU | - |
 | **activecampaign** | Email automation + CRM | - |
 
-**Agent recommendation**: Resend for transactional (dev-friendly). Postmark for deliverability. Customer.io for advanced automation. Kit for creators. Beehiiv for newsletters. Klaviyo for e-commerce email/SMS. ActiveCampaign for email + CRM combo.
+**Agent recommendation**: Resend for transactional (dev-friendly). Sequenzy for lifecycle email, sequences, and agent-driven email marketing. Postmark for deliverability. Customer.io for advanced automation. Kit for creators. Beehiiv for newsletters. Klaviyo for e-commerce email/SMS. ActiveCampaign for email + CRM combo.
 
 ### SMS / Messaging
 

tools/integrations/sequenzy.md

@@ -0,0 +1,306 @@
+# Sequenzy
+
+Email marketing platform for lifecycle campaigns, automation sequences, subscriber management, transactional email, and analytics.
+
+## Capabilities
+
+| Integration | Available | Notes |
+|-------------|-----------|-------|
+| API | ✓ | REST API for subscribers, tags, events, campaigns, sequences, templates, transactional email, analytics, and webhooks |
+| MCP | ✓ | `@sequenzy/mcp` stdio server for agent clients |
+| CLI | ✓ | `@sequenzy/cli` for subscriber operations, transactional sends, and stats |
+| SDK | - | Use the REST API directly |
+
+## Authentication
+
+- **Type**: API Key
+- **Header**: `Authorization: Bearer ***`
+- **Base URL**: `https://api.sequenzy.com/api/v1`
+- **Legacy base URL**: `https://api.sequenzy.com/v1`
+- **Environment variable**: `SEQUENZY_API_KEY`
+
+## MCP
+
+### Quick setup
+
+```bash
+npx @sequenzy/setup
+```
+
+The setup wizard logs in, creates a personal API key, and configures supported MCP clients when possible.
+
+### Manual MCP server config
+
+```json
+{
+  "mcpServers": {
+    "sequenzy": {
+      "command": "npx",
+      "args": ["-y", "@sequenzy/mcp"],
+      "env": {
+        "SEQUENZY_API_KEY": "seq_user_your_key_here"
+      }
+    }
+  }
+}
+```
+
+## CLI
+
+### Install
+
+```bash
+# Using npx
+npx sequenzy --help
+
+# Or install globally
+npm install -g @sequenzy/cli
+```
+
+### Login
+
+```bash
+sequenzy login
+sequenzy whoami
+```
+
+### Common commands
+
+```bash
+# Subscribers
+sequenzy subscribers list
+sequenzy subscribers list --tag vip
+sequenzy subscribers add user@example.com --tag premium --attr plan=pro
+sequenzy subscribers get user@example.com
+sequenzy subscribers remove user@example.com
+
+# Transactional email
+sequenzy send user@example.com --template welcome --var name=John
+sequenzy send user@example.com --subject "Hello" --html "<h1>Hi!</h1>"
+
+# Analytics
+sequenzy stats
+sequenzy stats --period 30d
+sequenzy stats --campaign camp_abc123
+sequenzy stats --sequence seq_xyz789
+```
+
+## Common Agent Operations
+
+### Get account
+
+```bash
+GET https://api.sequenzy.com/api/v1/account
+
+Authorization: Bearer ***
+```
+
+### List subscribers
+
+```bash
+GET https://api.sequenzy.com/api/v1/subscribers?page=1&limit=20&status=active&query=john&tags=customer,vip
+
+Authorization: Bearer ***
+```
+
+### Create or update subscriber
+
+```bash
+POST https://api.sequenzy.com/api/v1/subscribers
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "email": "user@example.com",
+  "firstName": "John",
+  "lastName": "Doe",
+  "tags": ["customer", "newsletter"],
+  "customAttributes": {
+    "plan": "pro"
+  }
+}
+```
+
+### Add tag to subscriber
+
+```bash
+POST https://api.sequenzy.com/api/v1/subscribers/tags
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "email": "user@example.com",
+  "tag": "vip"
+}
+```
+
+### Trigger event for subscriber
+
+```bash
+POST https://api.sequenzy.com/api/v1/subscribers/events
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "email": "user@example.com",
+  "event": "trial_started",
+  "properties": {
+    "plan": "pro"
+  }
+}
+```
+
+### List campaigns
+
+```bash
+GET https://api.sequenzy.com/api/v1/campaigns
+
+Authorization: Bearer ***
+```
+
+### Create draft campaign
+
+Create a draft campaign and linked email. A sender profile must already be configured.
+
+```bash
+POST https://api.sequenzy.com/api/v1/campaigns
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "name": "April Launch",
+  "subject": "A quick update",
+  "labels": ["launch"],
+  "html": "<p>Hello there!</p>"
+}
+```
+
+### Send campaign test
+
+```bash
+POST https://api.sequenzy.com/api/v1/campaigns/{campaignId}/test
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "to": "reviewer@example.com"
+}
+```
+
+### Schedule campaign
+
+```bash
+POST https://api.sequenzy.com/api/v1/campaigns/{campaignId}/schedule
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "scheduledAt": "2026-05-20T15:00:00Z"
+}
+```
+
+### List sequences
+
+```bash
+GET https://api.sequenzy.com/api/v1/sequences
+
+Authorization: Bearer ***
+```
+
+### Enable or disable sequence
+
+```bash
+POST https://api.sequenzy.com/api/v1/sequences/{sequenceId}/enable
+POST https://api.sequenzy.com/api/v1/sequences/{sequenceId}/disable
+
+Authorization: Bearer ***
+```
+
+### Send transactional email
+
+Send via a saved template slug or by passing direct subject/body content.
+
+```bash
+POST https://api.sequenzy.com/api/v1/transactional/send
+
+Authorization: Bearer ***
+Content-Type: application/json
+
+{
+  "to": "user@example.com",
+  "slug": "welcome",
+  "variables": {
+    "name": "John"
+  },
+  "subscriberExternalId": "user_123"
+}
+```
+
+### Get metrics
+
+```bash
+GET https://api.sequenzy.com/api/v1/metrics
+GET https://api.sequenzy.com/api/v1/metrics/campaigns/{campaignId}
+GET https://api.sequenzy.com/api/v1/metrics/sequences/{sequenceId}
+GET https://api.sequenzy.com/api/v1/metrics/recipients
+
+Authorization: Bearer ***
+```
+
+### Webhooks
+
+```bash
+GET https://api.sequenzy.com/api/v1/webhooks
+POST https://api.sequenzy.com/api/v1/webhooks
+PATCH https://api.sequenzy.com/api/v1/webhooks/{id}
+DELETE https://api.sequenzy.com/api/v1/webhooks/{id}
+POST https://api.sequenzy.com/api/v1/webhooks/{id}/test
+
+Authorization: Bearer ***
+```
+
+## Key Concepts
+
+- **Subscribers** - Contacts with email, status, tags, custom attributes, and optional external IDs
+- **Tags** - Lightweight labels used for targeting and segmentation
+- **Segments** - Dynamic subscriber groups based on attributes or engagement
+- **Campaigns** - Draftable and schedulable one-time marketing sends
+- **Sequences** - Automated lifecycle flows that can be enabled, disabled, and measured
+- **Templates** - Reusable email content for transactional and marketing workflows
+- **Transactional emails** - Single-recipient or small batch sends triggered by product events
+- **Engagement metrics** - Sent, delivered, bounced, opened, clicked, unsubscribed, and derived rates
+
+## Safety Notes
+
+- Inspect account, sender profile, audience, and target objects before mutating anything.
+- Prefer creating drafts and sending tests before scheduling or enabling live delivery.
+- Do not schedule a campaign, enable a sequence, or send a live transactional email without explicit approval.
+- Use recipient status, bounce, complaint, and unsubscribe data to avoid sending to suppressed contacts.
+- Use direct API calls for high-volume or scripted operations; use MCP or CLI for agent-driven interactive workflows.
+
+## When to Use
+
+- Managing subscribers, tags, lists, and segments
+- Drafting and scheduling lifecycle campaigns
+- Building onboarding, activation, retention, or winback sequences
+- Sending product-triggered transactional emails
+- Reviewing campaign, sequence, and recipient engagement metrics
+- Connecting AI agents to email marketing operations through MCP
+
+## Rate Limits
+
+- Check the latest Sequenzy API documentation for plan-specific limits.
+- Use pagination for list endpoints; subscriber lists support `page` and `limit` with a maximum limit of 100.
+
+## Relevant Skills
+
+- emails
+- onboarding
+- analytics
+- launch