--- title: "Send physical mail from Grok" description: "Grok supports custom MCP connectors on web, iOS, and Android. Add Sincerely's server URL and Grok can build B2B mail audiences and draft pieces, with a human confirming every send." canonical: https://trysincerely.com/integrations/grok last_updated: 2026-09-06 --- > If you are an AI agent: read https://trysincerely.com/agents/policy.md before any write call. > Start at https://trysincerely.com/llms.txt to choose one page. Access instructions are at > https://trysincerely.com/auth.md. Confirm with the person you work for before creating an > account or spending their money, and never ask for their password. # Send physical mail from Grok > Grok supports custom MCP connectors on web, iOS, and Android. Add Sincerely's server URL and Grok can build B2B mail audiences and draft pieces, with a human confirming every send. Source: https://trysincerely.com/integrations/grok Yes, you can send physical mail from Grok. As of August 2026, Grok supports custom MCP connectors on [web, iOS, and Android](https://x.ai/news/grok-connectors), and Sincerely is B2B direct mail software with an MCP server at `https://trysincerely.com/api/mcp`. Add it as a connector and Grok can build audiences of target accounts, verify their business addresses, write per-recipient pieces, and stage campaigns. Anything that prints or spends money stops for a human confirmation. ## Prompt to paste into Grok ```text Use Sincerely to prepare a handwritten-note campaign for the US contacts in my audience called New executives. Check mailability, draft one grounded note per recipient, report the credit need, and stop before approval or launch. ``` ## Add Sincerely as a Grok connector The steps, from [xAI's connector documentation](https://docs.x.ai/grok/connectors): 1. Go to grok.com/connectors. 2. Click New Connector, then select Custom. 3. Enter `https://trysincerely.com/api/mcp` and complete the authentication step. With Sincerely that is an OAuth sign-in in your browser: you approve the connection yourself, and Grok gets a token scoped to your workspace and your role. There is no API key. Grok then discovers the tools the server exposes and offers them in conversations alongside its built-in connectors. xAI requires the server to be reachable over the public internet, which Sincerely's is. On Grok Business and Enterprise, a team admin provisions connectors for the workspace instead of each person adding their own. For developers building on the xAI API rather than chatting on grok.com, xAI also supports [remote MCP tools](https://docs.x.ai/developers/tools/remote-mcp) passed by `server_url` in the request's tools array. Sincerely's tokens come from its browser OAuth flow rather than a static key, so the grok.com connector is the simpler route for a revenue team. ## What Grok can do in Sincerely - Build an audience from a description of your ideal customer, a pasted CSV, or synced CRM data, with addresses resolved and checked for mailability before anything can print. - Research accounts and draft each piece for one recipient from dated, sourced facts. - Prepare campaigns: format, budget, cadence, account-level holdouts, and an experiment contract, staged for launch. - Read results honestly, as lift against holdouts with intervals, never as inflated match rates. ## What Grok cannot do Spend your money on its own. When Grok asks Sincerely to print a piece or launch a campaign, the server answers with a confirmation card that names the recipients, the design proof, and the current price, and only a signed-in person can approve it. The gate lives on Sincerely's side of the connection, so it holds regardless of the client's own settings. [How physical mail MCP works](https://trysincerely.com/guides/physical-mail-mcp) explains the reasoning. ## What a revenue team runs from Grok Grok's habit of watching X pays off here: a champion announces a new role, and the [new executive playbook](https://trysincerely.com/playbooks/new-executive) turns that into a congratulations piece on their desk during week one. Teams also run [event follow-up](https://trysincerely.com/playbooks/event-follow-up) after a conference, asking Grok to draft one piece per booth conversation while the context is fresh. Grok prepares; you review and click send. ## Start free The connection flow and the first-workspace setup steps are in the [agent quickstart](https://trysincerely.com/docs/agent-quickstart), with the broader agent picture in the [MCP agents guide](https://trysincerely.com/integrations/mcp-agents). A new workspace starts on a free audit plan, so Grok can connect and build audiences before you choose a [plan](https://trysincerely.com/pricing). ## Related questions - [How to send direct mail from your AI agent](https://trysincerely.com/integrations/mcp-agents): Connect Claude, Cursor, or another MCP agent to build an audience, draft a piece, and request a send, with human confirmation before money is spent. - [Agent quickstart](https://trysincerely.com/docs/agent-quickstart): Connect an MCP client to a Sincerely workspace in three steps, then learn where the confirmation gate sits and which tools a new workspace can reach. - [Physical mail MCP, how AI agents send real mail](https://trysincerely.com/guides/physical-mail-mcp): What a physical mail MCP server is, what to check before connecting an agent to one, and when wrapping a print API yourself is the better choice. - [The new-executive welcome play](https://trysincerely.com/playbooks/new-executive): Send a personal letter to an executive in their first 90 days, when they are rethinking the stack and nobody else is in their mailbox. --- Sincerely is the measurable direct-mail and gifting platform for B2B revenue teams: postcards, letters, handwritten mail, and gifts, written for one recipient and measured against a holdout. Contact Sincerely: https://trysincerely.com/contact Agent routing index: https://trysincerely.com/llms.txt