Connect Postwire to your AI

Steps checked against the official Anthropic and OpenAI documentation on …. Both products change often; if a menu looks different, follow the current official documentation linked below.

Before you start

Create a Postwire account and verify your email address.
Connect a mailbox in your dashboard under My Mailboxes. Postwire tests the connection before saving it.
Stay signed in to Postwire in the same browser. While connecting, your AI app opens a Postwire page where you choose permissions and mailboxes.

MCP server URL

Claude

Pro / Max / Free: on claude.ai (web) or Claude Desktop, open Customize → Connectors, click + Add, then Add custom connector. Team / Enterprise: an Owner opens Organization settings → Connectors, clicks Add, hovers Custom, then chooses Web.
Name: Postwire. Remote MCP server URL: https://…/mcp
For the OAuth client choose Use Claude’s published identity (Recommended). Leave client ID and secret empty.
Claude opens Postwire. Sign in to your Postwire account, review the permissions, choose which mailboxes Claude may use, then click Allow access.
In a chat, click + at the lower left, open Connectors, switch Postwire on, and ask: List my mailboxes.

Eligibility

Custom connectors using remote MCP are available on Claude Free (one custom connector), Pro, Max, Team and Enterprise plans. On Team and Enterprise an Owner (or a role allowed to manage connectors) adds the connector for the organization.

Mobile

Add the connector on the web or in Claude Desktop first. Once added, it is available in the Claude mobile apps too. Anthropic’s documentation does not describe adding custom connectors from the mobile apps. The Postwire approval page works in a mobile browser.

Revoke access

Remove the connector in Claude (Customize → Connectors → ⋯ → Remove), and revoke it in Postwire under AI Connections. Revoking in Postwire takes effect immediately.

Troubleshooting

“Couldn’t reach the MCP server”: check that the URL ends in /mcp exactly as shown above.
“Authorization failed”: complete the Postwire sign-in in the window Claude opens, and make sure your email address is verified.
A tool says a permission is missing: reconnect and tick that permission on the Postwire consent page.
Official docs: Get started with custom connectors.

ChatGPT

On the ChatGPT website, go to chatgpt.com/plugins, select +, then Add custom MCP server.
Enter a name (Postwire) and a short description. Under Connection, enter https://…/mcp.
Choose OAuth authentication, review the risk warning and select I understand and want to continue.
Create it, review the tools Postwire reports, then install it.
Sign in to your Postwire account when prompted, choose permissions and mailboxes, and click Allow access.
Start a new conversation, type @, select Postwire and ask: List my mailboxes.

Eligibility

OpenAI documents custom MCP server connections for ChatGPT Business and Enterprise/Edu on the web; in a Business workspace only admins and owners can create them. We could not confirm from OpenAI’s documentation whether personal Plus or Pro accounts can add custom MCP servers. If the option is missing, your plan or workspace policy does not allow it.

Mobile

OpenAI’s documentation directs you to ChatGPT on the web to add custom MCP servers and does not confirm mobile support. Treat mobile as unavailable unless it appears in your app.

Confirmations

ChatGPT asks you to confirm before any tool that changes something (drafts, sending, moving, marking). Read-only tools such as search do not need confirmation.

Revoke access

Remove or disable Postwire in ChatGPT, and revoke it in Postwire under AI Connections.

Troubleshooting

No “Add custom MCP server” option: your plan or workspace does not permit it, or a workspace admin must enable it.
Sign-in loops or fails: sign in to Postwire in the window that opens and make sure your email address is verified.
After Postwire updates: open the connection in ChatGPT and select Refresh, then start a new conversation.
Official docs: Add a custom MCP server.

Things to ask

“List my mailboxes.”
“Find my latest invoice.”
“Summarize today’s unread emails.”
“Find the quotation sent by my supplier.”
“Draft a reply to the most recent customer inquiry.”
“Prepare a response and show me before sending.”

What your AI can do

Read: list_mailboxes, list_folders, search_emails, read_email, read_thread, get_attachment_text, inbox_digest, list_identities
Drafts: create_draft, update_draft, get_draft, list_drafts, delete_draft
Send: send_draft — existing drafts only, after your approval
Organize: mark_emails, move_emails

There is no single-step “compose and send” tool and no tool that permanently deletes mail.