Thunderbird MCP 0.4.0 — mail workflows and automation

Thunderbird MCP 0.4.0 expands the mail server to 56 tools, with the same Codex, Claude, OpenCode and terminal integrations.

• Enforced tool profiles/account boundaries; editable revisioned drafts, forwards, HTML/inline composition and sender identities.
• Live triage and mailbox operations, stable search continuation, reviewed batch exports, operation history and cancellation.
• BYO OAuth enrollment, Gmail API/Graph adapters, durable events and explicitly approved scheduled delivery.
• Authenticated HTTP, incremental Maildir indexing, optional local OCR, Windows installation, and a separately pinned native Thunderbird companion for contacts/calendar/tasks/filters/settings.

See the workflow guide, installation instructions, and roadmap evidence.

Validation includes 329 synthetic tests (two expected Linux-run skips), the 78-message/13-case keyword benchmark with precision/recall/MRR of 1.0, isolated wheel and uv-tool installation, actual stdio/HTTP boundary checks, and real OCR of synthetic PNG/scanned-PDF fixtures. All five jobs in the release CI matrix passed: Linux Python 3.10–3.12, macOS Intel/Python 3.12, and native Windows installation/Python 3.12. Intel macOS uses ONNX Runtime 1.23.x and Python 3.10–3.13; its cryptography source build needs Xcode Command Line Tools, Rust and OpenSSL (upstream instructions). No completed Apple Silicon run is claimed for this release.

Verification limits: real provider consent, delivery, mailbox mutations/IDLE, and interactive native-addon operations were not exercised with the user's mail. OAuth application/tenant approval, installed OCR engines/languages, and the separate native addon remain explicit setup requirements. No mail was sent to validate this release.

Download the wheel or source archive below; SHA256SUMS verifies both artifacts. MIT licensed. Only project code, synthetic tests and documentation are published.

v0.3.1: verified installs and a synthetic mail demo

Thunderbird MCP now installs from a release wheel without requiring a source checkout. The installer uses the correct Python environment, preserves uv tool command links, and keeps installed-package mail data in the user's data directory. Existing checkout databases keep their original paths.

Included

• MIT licence, package metadata, and downloadable wheel/source packages with SHA-256 checksums.
• A runnable synthetic demo: find an invoice inside a PDF, reuse its reference in another process, read the thread, and prepare an unsent reply.
• Installation and troubleshooting guide, plus forms for installation successes and bugs.
• macOS Thunderbird profile discovery and support for percent signs in profile paths.
• Desktop keyring session initialization for installed console commands.
• Automated fresh-venv and uv tool installation checks with real MCP protocol calls.

Verification

185 synthetic tests, the 13-case keyword benchmark, package builds, and clean installation checks pass on Linux Python 3.10–3.12 and macOS Python 3.12. CI results.

The demo and installation checks use generated mail and isolated homes. Application checks block network access and disable keyring use; no mail is sent and no AI model is required. The server still exposes 23 tools.

Linux is the primary tested desktop. macOS CI does not establish a full Thunderbird/keychain/client desktop integration; native Windows deployment and provider browser OAuth consent remain unverified. Independent installation feedback is still needed: report what worked or failed.

Downloads

Install the wheel with uv tool install, or unpack the source distribution for the demo, tests, and dependency lock. SHA256SUMS covers both packages. See the full changelog.