Kit integration for multiplayer collaboration with AI agents using Claude Code or Codex

Add an existing subscriber to a form by their IDs. This action associates a subscriber with a form in Kit. The subscriber must already exist in your Kit account (use KIT_LIST_SUBSCRIBERS to find them). The form must also exist (use KIT_LIST_FORMS to find valid form IDs). Returns HTTP 201 if the subscriber is newly added to the form, or HTTP 200 if they were already associated with the form. Both cases are considered successful operations. Important: This action requires both form_id and subscriber_id (aliased as 'id' in requests). An optional referrer URL can be provided for tracking purposes and will have its UTM parameters automatically parsed.

Tool to add an existing subscriber to a form using their email address. Use when you know the subscriber's email but not their ID. The subscriber must already exist in your Kit account before adding them to a form. Returns HTTP 201 if the subscriber is newly added to the form, or HTTP 200 if they were already associated with the form.

Tool to create a new broadcast (email campaign) to send to subscribers. Use when you need to draft, schedule, or immediately publish an email broadcast. To save as draft, set send_at to null; to schedule, provide a future send_at timestamp; to publish to web, set public to true.

Tool to create a new custom field for subscriber data. Use when you need to store extra attributes for subscribers.

Tool to create a new subscriber or update an existing one (upsert). If a subscriber with the provided email address does not exist, creates one. If already exists, updates the first name.