gmail-mcp-oauth Privacy Policy

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gmail-mcp-oauth ("the service") is an OAuth-authenticated Model Context Protocol (MCP) server that connects to the Google Gmail API on your behalf. It is operated by Welch Commerce Systems, a DBA of Welch Products LLC ("Welch Commerce Systems," "we," "us," or "our"). This privacy policy explains what Google user data the service accesses, and how it uses, stores, shares, retains, and deletes that data.

This policy applies to the instance of gmail-mcp-oauth that Welch Commerce Systems operates and has registered with Google for OAuth access. gmail-mcp-oauth is also open-source software; if you deploy your own instance from the source code, you are the operator and data controller of that deployment and this policy does not apply to it.

How the service works

• You authenticate to the service through Auth0 and link one or more Google (Gmail) accounts.
• Linking sends you to Google's own consent screen, where you grant the OAuth scopes the service requests. Google then issues the service an OAuth refresh token for the account you authorized.
• Once an account is linked, an MCP client you connect (for example, an AI assistant such as Claude) can call Gmail tools through the service, and the service calls the Gmail API on your behalf using your token.

Google user data we access

With the OAuth scopes you approve on Google's consent screen, the service accesses the Gmail API to:

• read your email messages, threads, labels, drafts, and related metadata; and
• send, reply to, draft, modify, label, archive, and delete messages on your behalf, where you have granted the corresponding permissions.
• create, read, and modify your Gmail filters and basic account settings (for example, to set up and maintain inbox rules), where you have granted the corresponding permissions.

The service requests only the scopes needed for the Gmail features you use. You see and approve every scope on Google's consent screen before any access is granted, and you can decline.

How we use Google user data

We use the Google user data the service accesses solely to provide the Gmail features you invoke through your connected MCP client. The service acts only in response to your requests, or to requests from a client you have connected and authorized. We do not use your Google user data for any purpose other than providing these user-facing features.

How we store Google user data

• OAuth refresh tokens. We store the Google OAuth refresh token for each account you link so the service can act on your behalf without re-prompting you for every request. Refresh tokens are encrypted at rest using Fernet (AES-128-CBC with HMAC-SHA256 authentication) before being written to our PostgreSQL database, and are keyed to your authenticated identity and the specific mailbox address. A token is decrypted only at the moment it is needed to call the Gmail API; it is never written to logs and never returned in any response.
• Email content. The contents of your messages (subjects, bodies, attachments, and so on) are retrieved from the Gmail API at the time of each request and returned to the MCP client that made the request. We do not store the contents of your email messages in our database.
• Operational records. We keep short-lived records used only to complete the account-linking flow, and audit logs of tool operations. These audit records describe the operation performed (for example, which tool ran and when), not the contents of your messages.

How we share Google user data

We do not sell your Google user data, and we do not share it with third parties for their own purposes. Your data flows only to:

• Google, the provider of the Gmail API; and
• the MCP client you have connected and authorized (for example, your AI assistant), which receives the results of the requests it makes.

We do not transfer your Google user data to advertising platforms, data brokers, or information resellers.

Limited Use

gmail-mcp-oauth's use and transfer of information received from Google APIs to any other app will adhere to the Google API Services User Data Policy, including the Limited Use requirements. In particular, we do not use Google user data to serve advertising; we do not transfer or sell it to third parties for advertising or other unrelated purposes; we do not use it to train generalized or non-personalized artificial-intelligence or machine-learning models; and we allow humans to read your data only with your explicit consent, where necessary for security purposes or to comply with applicable law, or where the data has been aggregated and anonymized for internal operations.

Data retention and deletion

• We retain your encrypted refresh token only for as long as your account remains linked. When you unlink an account, or when you revoke the service's access from your Google Account, the corresponding refresh token is deleted from our database and the service can no longer access that mailbox.
• You can review and revoke the service's access at any time from your Google Account at myaccount.google.com/permissions.
• Short-lived linking records expire automatically. Audit logs are retained for a limited period for security and troubleshooting and contain operation metadata only, not message content.

How we protect your data

The service encrypts refresh tokens at rest, supports encryption-key rotation, authenticates every request, gates account access behind an explicit allowlist, and runs in a hardened, non-root container. Decrypted tokens exist only transiently in memory at the moment of an API call.

Children's privacy

The service is intended for business and developer use and is not directed to children. We do not knowingly collect data from children.

Changes to this policy

If we change this privacy policy, we will post the updated version at this same URL and revise the "Last updated" date above. Material changes will be reflected here before they take effect.

Contact

For questions about this privacy policy or the service's handling of your data, contact Welch Commerce Systems at [email protected].