Tools Reference

This reference documents every tool available through Lettr’s MCP servers. Some tools are available on both the remote and local servers, while others are exclusive to one.

The remote server uses underscores in tool names (e.g., send_email) while the local server uses hyphens (e.g., send-email). The functionality is equivalent.

Tool Availability

Category	Tool	Remote	Local
Sending	send_email	Yes	Yes
Sending	send_template_email	Yes	—
Templates	list_templates	Yes	Yes
Templates	get_template	Yes	Yes
Templates	create_template	Yes	Yes
Templates	update_template	Yes	Yes
Templates	delete_template	—	Yes
Templates	get_merge_tags	—	Yes
Domains	list_sending_domains / list_domains	Yes	Yes
Domains	list_tracking_domains	Yes	—
Domains	list_inbound_domains	Yes	—
Domains	list_storage_domains	Yes	—
Domains	create_domain	—	Yes
Domains	get_domain	—	Yes
Domains	delete_domain	—	Yes
Domains	verify_domain	—	Yes
Configuration	list_api_keys	Yes	—
Configuration	list_webhooks	Yes	Yes
Configuration	get_webhook	—	Yes
Analytics	get_analytics	Yes	—
Analytics	list_template_stats	Yes	—
Monitoring	browse_email_events	Yes	—
Monitoring	browse_api_logs	Yes	—

Email Sending

send_email

Send an email with plain text, HTML, or AMP HTML content. Supports merge tags for variable substitution. Available on: Remote, Local

Parameter	Type	Required	Description
`from`	string	Yes	Sender email address. Must be from a verified sending domain.
`to`	string	Yes	Recipient email address.
`subject`	string	Yes	Email subject line (max 998 characters).
`html`	string	No	HTML content. Supports merge tags like `{{variable_name}}`.
`text`	string	No	Plain text content. Supports merge tags.
`amp_html`	string	No	AMP HTML content for interactive emails.
`from_name`	string	No	Display name for the sender.
`reply_to`	string	No	Reply-to email address.
`cc`	string	No	CC recipient email address.
`bcc`	string	No	BCC recipient email address.
`substitution_data`	object	No	Key-value pairs for merge tag substitution.

Example prompt: “Send a welcome email to john@example.com from hello@mycompany.com with the subject ‘Welcome to Acme‘“

send_template_email

Send an email using a pre-defined template specified by its slug. Available on: Remote only

Parameter	Type	Required	Description
`from`	string	Yes	Sender email address. Must be from a verified sending domain.
`to`	string	Yes	Recipient email address.
`subject`	string	Yes	Email subject line. Can include merge tags.
`template_slug`	string	Yes	The slug of the template to use (e.g., `welcome-email`).
`from_name`	string	No	Display name for the sender.
`reply_to`	string	No	Reply-to email address.
`project_id`	integer	No	Project ID where the template is located. Uses default project if omitted.
`template_version`	integer	No	Specific version number. Uses active version if omitted.
`substitution_data`	object	No	Key-value pairs for merge tag substitution.

Example prompt: “Send the order-confirmation template to customer@example.com with order_id 12345”

On the local server, the send-email tool supports template-based sending directly via a template_slug parameter.

Template Management

list_templates

Lists all email templates for your team with metadata including name, slug, editor type, version count, and merge tags. Available on: Remote, Local

Parameter	Type	Required	Description
`project_id`	integer	No	Filter templates by project. Returns templates from all projects if omitted.

Example prompt: “List all my email templates” or “What templates are in project 3?“

get_template

Gets detailed information about a specific template, including its HTML content and merge tags. Available on: Remote, Local

Parameter	Type	Required	Description
`template_id`	integer	No	The numeric ID of the template.
`template_slug`	string	No	The slug of the template (e.g., `welcome-email`).
`project_id`	integer	No	Project ID to narrow the search when using a slug.

Provide either template_id or template_slug to identify the template.

Example prompt: “Show me the HTML content of the welcome-email template”

create_template

Creates a new Custom HTML email template. Available on: Remote, Local

Parameter	Type	Required	Description
`name`	string	Yes	Display name for the template.
`folder_id`	integer	Yes	The folder ID where the template will be created.
`slug`	string	No	URL-friendly identifier. Auto-generated from name if omitted.
`project_id`	integer	No	Project ID. Uses default project if omitted.
`html`	string	No	Initial HTML content for the template.
`subject`	string	No	Default subject line for the template.

Example prompt: “Create a new template called ‘Invoice Reminder’ in folder 1 with a basic HTML layout”

update_template

Updates a template’s content and creates a new active version. Supports both Custom HTML and Topol editor templates. Available on: Remote, Local

Parameter	Type	Required	Description
`template_id`	integer	No	The numeric ID of the template.
`template_slug`	string	No	The slug of the template.
`project_id`	integer	No	Project ID to narrow the search when using a slug.
`html`	string	No	Updated HTML content (for Custom HTML templates).
`json`	string	No	Updated Topol editor JSON (for Topol templates).

Provide either template_id or template_slug to identify the template. Each update creates a new version automatically.

Example prompt: “Update the welcome-email template with new HTML content”

delete_template

Permanently deletes a template and all its versions. Available on: Local only

Parameter	Type	Required	Description
`template_id`	integer	No	The numeric ID of the template.
`template_slug`	string	No	The slug of the template.
`project_id`	integer	No	Project ID to narrow the search when using a slug.

Example prompt: “Delete the old-welcome-email template”

get_merge_tags

Retrieves the merge tag variables that a template expects, so you know which substitution data to provide when sending. Available on: Local only

Parameter	Type	Required	Description
`template_id`	integer	No	The numeric ID of the template.
`template_slug`	string	No	The slug of the template.
`project_id`	integer	No	Project ID to narrow the search when using a slug.

Example prompt: “What merge tags does the order-confirmation template expect?”

Domain Management

list_sending_domains / list_domains

Lists all sending domains configured for your team with verification status, DNS configuration status, and whether they can be used for sending. Available on: Remote (list_sending_domains), Local (list-domains) Parameters: None Example prompt: “Show me all my sending domains and their verification status”

list_tracking_domains

Lists all tracking domains configured for your team. Tracking domains are used to track email opens and clicks with your own branded domain. Available on: Remote only Parameters: None Example prompt: “What tracking domains do I have set up?“

list_inbound_domains

Lists all inbound domains configured for your team. Inbound domains receive emails via MX records. Available on: Remote only Parameters: None

list_storage_domains

Lists all email storage domains configured for your team. Storage domains serve email assets (images, files) from your branded domain. Available on: Remote only Parameters: None

create_domain

Registers a new sending domain. Available on: Local only

Parameter	Type	Required	Description
`domain`	string	Yes	The domain name to register (e.g., `notifications.example.com`).

Example prompt: “Add notifications.example.com as a sending domain”

get_domain

Gets detailed information about a sending domain, including its DNS records for SPF, DKIM, and DMARC setup. Available on: Local only

Parameter	Type	Required	Description
`domain_id`	string	Yes	The ID of the domain to retrieve.

Example prompt: “Show me the DNS records for my sending domain”

delete_domain

Removes a sending domain from your account. Available on: Local only

Parameter	Type	Required	Description
`domain_id`	string	Yes	The ID of the domain to delete.

Example prompt: “Remove the old.example.com sending domain”

verify_domain

Triggers DNS verification for a sending domain to check if SPF and DKIM records are properly configured. Available on: Local only

Parameter	Type	Required	Description
`domain_id`	string	Yes	The ID of the domain to verify.

Example prompt: “Verify the DNS records for my sending domain”

Configuration

list_api_keys

Lists all API keys for your team, showing each key’s name, key ID, prefix, permissions level, and IP whitelist configuration. Available on: Remote only Parameters: None Example prompt: “List my API keys and their permissions”

list_webhooks

Lists all webhooks configured for your team, including target URL, enabled status, event types, authentication type, and delivery health indicators. Available on: Remote, Local Parameters: None

get_webhook

Gets detailed information about a specific webhook, including its delivery status and configuration. Available on: Local only

Parameter	Type	Required	Description
`webhook_id`	string	Yes	The ID of the webhook to retrieve.

Example prompt: “Show me the details for my delivery webhook”

Analytics

get_analytics

Returns aggregate email delivery analytics with a daily breakdown, including targeted, accepted, bounced, and opened counts. Available on: Remote only

Parameter	Type	Required	Description
`from`	string	No	Start date in ISO 8601 format. Default: 7 days ago. Max 90 days back.
`to`	string	No	End date in ISO 8601 format. Default: now.

Example prompt: “Show me my email delivery stats for the last 30 days”

list_template_stats

Lists templates with delivery statistics broken down by campaign, including sent, delivered, opened, and bounced counts. Available on: Remote only

Parameter	Type	Required	Description
`project_id`	integer	No	Filter by project. Returns stats for all projects if omitted.
`from`	string	No	Start date in ISO 8601 format. Default: 30 days ago.
`to`	string	No	End date in ISO 8601 format. Default: now.

Example prompt: “Which of my templates has the best open rate this month?”

Monitoring

browse_email_events

Browse email delivery events with optional filtering and pagination. Available on: Remote only

Parameter	Type	Required	Description
`limit`	integer	No	Number of events to return (10, 25, 50, or 100). Default: 25.
`recipient`	string	No	Filter by recipient email address. Supports partial matching.
`from`	string	No	Start date/time in ISO 8601 format.
`to`	string	No	End date/time in ISO 8601 format.
`event_type`	string	No	Filter by event type: `delivery`, `injection`, `open`, `initial_open`, `click`, `bounce`, `out_of_band`, `delay`, `spam_complaint`, `policy_rejection`, `generation_rejection`, `generation_failure`, `list_unsubscribe`, `link_unsubscribe`, `amp_open`, `amp_click`
`cursor`	string	No	Pagination cursor from a previous response.

Example prompt: “Show me the last 10 bounced emails” or “What emails were sent to john@example.com today?“

browse_api_logs

Browse API request logs with optional filtering and pagination. Available on: Remote only

Parameter	Type	Required	Description
`limit`	integer	No	Number of log entries (1, 20, 50, or 100). Default: 20.
`from`	string	No	Start date/time in ISO 8601 format. Max 30 days back. Default: 7 days ago.
`to`	string	No	End date/time in ISO 8601 format. Default: now.
`api_key_name`	string	No	Filter by API key name (case-insensitive).
`user_agent`	string	No	Filter by client type: `php`, `curl`, `nodejs`, `python`, `ruby`, `go`, `rust`, `java`, `dotnet`, `smtp`, `other`
`status`	integer	No	Filter by HTTP status code (e.g., 200, 400, 500).
`cursor`	string	No	Pagination cursor from a previous response.

Example prompt: “Show me failed API requests from the last 24 hours” or “Were there any 500 errors today?”

Remote Server Setup

Connect via OAuth from Claude.ai, ChatGPT, and other AI clients

Local Server Setup

Install the lettr-mcp package for your IDE or CLI

API Reference

Full REST API documentation

Template Language

Merge tag syntax and template variables

Documentation

Quickstart

Learn

Integrations

Resources

Tools Reference

Tool Availability

Email Sending

send_email

send_template_email

Template Management

list_templates

get_template

create_template

update_template

delete_template

get_merge_tags

Domain Management

list_sending_domains / list_domains

list_tracking_domains

list_inbound_domains

list_storage_domains

create_domain

get_domain

delete_domain

verify_domain

Configuration

list_api_keys

list_webhooks

get_webhook

Analytics

get_analytics

list_template_stats

Monitoring

browse_email_events

browse_api_logs

Remote Server Setup

Local Server Setup

API Reference

Template Language

​Tool Availability

​Email Sending

​send_email

​send_template_email

​Template Management

​list_templates

​get_template

​create_template

​update_template

​delete_template

​get_merge_tags

​Domain Management

​list_sending_domains / list_domains

​list_tracking_domains

​list_inbound_domains

​list_storage_domains

​create_domain

​get_domain

​delete_domain

​verify_domain

​Configuration

​list_api_keys

​list_webhooks

​get_webhook

​Analytics

​get_analytics

​list_template_stats

​Monitoring

​browse_email_events

​browse_api_logs

​Related Topics

Remote Server Setup

Local Server Setup

API Reference

Template Language

Tool Availability

Email Sending

send_email

send_template_email

Template Management

list_templates

get_template

create_template

update_template

delete_template

get_merge_tags

Domain Management

list_sending_domains / list_domains

list_tracking_domains

list_inbound_domains

list_storage_domains

create_domain

get_domain

delete_domain

verify_domain

Configuration

list_api_keys

list_webhooks

get_webhook

Analytics

get_analytics

list_template_stats

Monitoring

browse_email_events

browse_api_logs

Related Topics