Select which accounts the MCP server can access. Saving a changed selection with all accounts checked allows current and future accounts. Select at least one account before saving.
Encrypted message bodies, attachments, and inline images are withheld from MCP clients by default.
Opaque-signed S/MIME messages are also withheld while encrypted message access is off.
Thunderbird may still decrypt S/MIME messages locally. Enabling encrypted message access exposes
decrypted content to MCP clients and their AI providers, and allows direct replies and forwards
when skipReview is permitted.
While it is off, search and recent-message tools show the outer subject without a preview for
messages Thunderbird has recorded as OpenPGP-encrypted, searches do not match them, and
displayMessage refuses encrypted messages. Thunderbird provides no reliable encryption marker for
all message headers, so some cached subjects may still contain decrypted protected headers.
When mail account access is restricted, calendars and address books are blocked unless you allow them below. These permissions allow access to all calendars or all address books. Without mail account restrictions, these two permissions are not required. Tool Access and other safety settings still apply: contact changes always require Allow contact writes below. These settings can only be changed here.
Uncheck tools to disable them. Disabled tools are hidden from MCP clients and cannot be called. Infrastructure tools (listAccounts, listFolders, getAccountAccess) cannot be disabled.
Once you restrict Tool Access, tools added by future updates start unchecked. Enable any new tools you want here and save. Tools you explicitly enable stay enabled.
Stable token mode keeps the same token across restarts. If the connection file leaks, the token stays valid until you regenerate or clear it. Changes apply next time the MCP server starts. The stored stable token is cleared on uninstall only while the add-on is enabled (best effort). If you disable the add-on before uninstalling, regenerate the token before using it again.
This setting is enabled by default. While enabled, MCP clients requesting
skipReview: true on sendMail, replyToMessage, forwardMessage,
createEvent, or createTask are rejected; the review window or dialog remains
available. Scheduling delivery through Send Later with saveDraft
and sendAt is also rejected; plain drafts remain available.
Re-enabling this block does not cancel already scheduled drafts.
Adding event attendees is blocked. Events with attendees other
than the calendar user are read-only through MCP: updates and deletions,
including individual occurrences, are rejected even when attendees are
omitted from the request. Exchange/Owl or CalDAV may email invitations,
updates, or cancellations with the event title and description without
review. Disabling this setting allows these writes, skipReview,
and scheduled drafts. Scheduling still requires the sendMail tool to be
enabled and an identity permitted by the unreviewed-send encryption checks.
Direct sendMail also requires at least one effective recipient, including enabled automatic Cc/Bcc. Direct mail sends, replies, and forwards require review when their conservative size estimate exceeds Thunderbird's positive large-message threshold, or the threshold/estimate cannot be read safely. The add-on does not change that preference. dryRunCompose reports the same blockers; review windows remain available.
Disabled by default. Enabling this lets MCP clients create, change, and run
filters that forward messages or reply from templates without a compose
review window. This setting is independent of Block skipReview.
Turning this off does not disable saved filters or stop Thunderbird from running them automatically. You can still disable or delete existing Forward/Reply rules through MCP.
Disabled by default. Enabling this lets MCP clients create, change, and delete contacts in your address books. Changes are saved immediately without a review step. Reading contacts does not require this permission. Tool Access still applies. If mail account access is restricted, also enable Allow all address books in Privacy. Turning this off blocks future MCP changes; it does not undo saved changes.