This connector processes private mail through the user's own Proton Mail Bridge instance. Treat every environment file, log, screenshot, and test artifact as sensitive.

Once the public repository is available, report vulnerabilities through a private GitHub security advisory. Do not open a public issue for a security report.

Do not include real message bodies, credentials, API keys, or mailbox exports in public issues.

• Keep Proton Mail Bridge bound to localhost where possible.
• Never send Bridge credentials over a remote plaintext or certificate-unverified IMAP/SMTP connection. The connector rejects those combinations for non-loopback Bridge hosts.
• Prefer local stdio MCP connections.
• Follow docs/HOSTING.md before exposing Streamable HTTP beyond localhost.
• Use OAuth/OIDC, HTTPS, Host validation, Origin validation, and rate limits for internet deployments.
• Keep .env files outside git and chmod them to user-only access.
• Use permanently_delete_message only after explicit user confirmation.