--- title: "Connect Mailbox Power to OnceOnly - APIANT.ai" description: "When \"New Contact Added to Group\" fires in Mailbox Power, your agent runs \"Add event\" in OnceOnly." canonical: "https://apiant.ai/connect/mailbox-power-to-onceonly" --- # Connect Mailbox Power to OnceOnly When **New Contact Added to Group** fires in [Mailbox Power](https://apiant.ai/connections/mailbox-power), your agent runs **Add event** in [OnceOnly](https://apiant.ai/connections/onceonly). Describe the whole flow and it is built, tested on every scenario and kept running. Mailbox Power **2** triggers Mailbox Power **4** actions OnceOnly **11** actions What the catalog holds today. Ask for anything missing and your agent reads the API documentation and adds it. ## What do you want Mailbox Power and OnceOnly to do together? Give your AI client this address. `https://mcp.apiant.ai` One connection does both: ask your client to act in an app once, or have it build an automation that keeps running. Any client that takes a remote MCP server. Nothing to install. Create your free account, then sign in once in your browser. ### Set it up in your client ### Claude Code Run this in the directory you want to work in. `claude mcp add --transport http -s project apiant-ai https://mcp.apiant.ai` Start Claude Code there, approve the server, and sign in in the browser page it opens. [Claude Code guide (opens in a new tab)](https://apiant.ai/docs/mcp/claude-code) ### Claude, web and desktop Open Customize, then Connectors, then Add custom connector, and paste the address. On Team and Enterprise an owner adds it first. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Cursor Add the address to your MCP configuration as a server URL. Cursor signs you in in your browser. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Zed Open Settings, then AI, then MCP Servers, then Add Server, then Add Remote Server. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Codex and the ChatGPT desktop app Open Settings, then MCP servers, then Add server, and choose Streamable HTTP. From the terminal, Codex takes the address with its own add command and then signs you in. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) ### Any other MCP client Paste the address where the client asks for a remote MCP server URL, and name the server apiant-ai where it lets you. APIANT's skills reach the client over the same connection. [Setup guide (opens in a new tab)](https://apiant.ai/docs/mcp) Example flows ## What Mailbox Power can start in OnceOnly - When **New Contact Added to Group** in Mailbox Power then **Add event** in OnceOnly - When **Updated Contact** in Mailbox Power then **Add policy** in OnceOnly Starting points drawn from the triggers and actions in the catalog today. Describe the flow you need, at any depth, and your agent builds it and tests every scenario before it ships. Everything your agent can do with Mailbox Power and OnceOnly ## Triggers and actions 2 triggers · 15 actions - Trigger **New Contact Added to Group** Triggers when a contact is added to the selected Mailbox Power contact group. - Trigger **Updated Contact** Triggers when a contact in Mailbox Power is added or any of its details change. - Action **Create or Update Contact** Creates a contact in Mailbox Power, or updates the existing contact whose name and address match. - Action **Delete Contact** Deletes a contact from your Mailbox Power account. - Action **List contacts** Returns every contact in the Mailbox Power account, including address, contact details and group membership. - Action **Remove Contact From Group** Removes a contact from a Mailbox Power contact group. - Action **Add event** Adds an event to an agent run's timeline in OnceOnly, such as a step starting, a tool call, or a failure. - Action **Add policy** Creates or updates the governance policy for an agent, such as rate limits, spend limits and allowed or blocked tools. - Action **Add tool** Creates or updates a tool in your OnceOnly tool registry, pointing at your backend URL. Returns the saved tool without its secret. - Action **Check & Lock** Checks an idempotency key and locks it if it is new, telling you whether the event is a first occurrence or a duplicate. - Action **Delete tool** Permanently deletes a tool from your OnceOnly tool registry. - Action **Get policy** Returns the governance policy configured for an agent. - Action **Get run** Returns a run's timeline: the run id, the total number of events and the list of events recorded for it. - Action **Get tool** Returns the details of a registered tool by name, including its URL, scope, enabled state and retry settings. - Action **List policies** Returns every agent policy on the OnceOnly account, each with its agent id and policy settings. - Action **List runs** Returns the runs recorded on your OnceOnly account, with each run's latest status and event count. - Action **List tools** Returns the tools registered in your OnceOnly tool registry for a scope. ## Each app on its own - [ **Mailbox Power** Mailbox Power enables you to engage your customers and stay top of mind with your clients by sending...](https://apiant.ai/connections/mailbox-power) - [ **OnceOnly** OnceOnly is an idempotency API that prevents duplicate automation runs by blocking repeated events in...](https://apiant.ai/connections/onceonly) Reviews ## What our customers say ## More from Mailbox Power - [ **Mailbox Power to Salesforce** Salesforce is a leading enterprise customer relationship management (CRM) platform.](https://apiant.ai/connect/mailbox-power-to-salesforce) - [ **Mailbox Power to Slack** Slack is a messaging platform for teams. Post messages, manage channels, users, reminders, and react to...](https://apiant.ai/connect/mailbox-power-to-slack) - [ **Mailbox Power to Mailchimp** Mailchimp marketing automation and email platform.](https://apiant.ai/connect/mailbox-power-to-mailchimp) - [ **Mailbox Power to Stripe** Stripe is a payment processing platform for online businesses.](https://apiant.ai/connect/mailbox-power-to-stripe) - [ **Mailbox Power to Shopify** Shopify is a commerce platform for online stores and retail point-of-sale.](https://apiant.ai/connect/mailbox-power-to-shopify) - [ **Mailbox Power to QuickBooks Online** QuickBooks Online accounting — manage customers, invoices, bills, payments, vendors, expenses, and more via...](https://apiant.ai/connect/mailbox-power-to-quickbooks-online) ## More into OnceOnly - [ **HubSpot to OnceOnly** HubSpot is your all-in-one stop for all of your marketing software needs.](https://apiant.ai/connect/hubspot-to-onceonly) - [ **Salesforce to OnceOnly** Salesforce is a leading enterprise customer relationship management (CRM) platform.](https://apiant.ai/connect/salesforce-to-onceonly) - [ **Slack to OnceOnly** Slack is a messaging platform for teams. Post messages, manage channels, users, reminders, and react to...](https://apiant.ai/connect/slack-to-onceonly) - [ **Google Sheets to OnceOnly** Google Sheets is Google's online spreadsheet app for creating, editing and sharing spreadsheets.](https://apiant.ai/connect/google-sheets-to-onceonly) - [ **Gmail to OnceOnly** Gmail is Google’s email service, featuring spam protection, search functions, and seamless integration with...](https://apiant.ai/connect/gmail-to-onceonly) - [ **Google Calendar to OnceOnly** Google Calendar is a time management tool providing scheduling features, event reminders, and integration...](https://apiant.ai/connect/google-calendar-to-onceonly) Questions ## Mailbox Power and OnceOnly, answered ### ### What can start an automation from Mailbox Power? Any of Mailbox Power's 2 triggers in the catalog, including New Contact Added to Group and Updated Contact. Describe the moment in plain language and your agent picks the right one. ### ### What can your agent do in OnceOnly when something happens in Mailbox Power? Any of OnceOnly's 11 actions, including Add event, Add policy, Add tool and Check & Lock. Your agent maps the data both ways and tests every scenario before it ships. ### ### Can it also run from OnceOnly to Mailbox Power? OnceOnly has no triggers in the catalog today, so automations start in Mailbox Power. If you need the other direction, ask: your agent reads OnceOnly's API documentation and adds it. ### ### Do I have to build a connector for Mailbox Power or OnceOnly? No. Both are in the catalog with their triggers and actions. You describe the automation; your agent builds it, tests every scenario and keeps it running. ### ### Can my AI client use Mailbox Power and OnceOnly without building an automation? Yes. With your AI client connected to APIANT, ask it to do something in either app once and it runs that action on the spot. Ask for an automation and your agent builds it, tests every scenario and keeps it running. One connection covers both. ### ### What happens when something fails? Your agent works that out for you. It plans the failure paths along with the happy path, then tests every scenario before it ships. ### ### Is there a free plan? Yes. Every plan includes the agent, including free, and building from your own AI client spends no assistant credits.