inbox-mcp

A privacy-preserving MCP server (built on FastMCP) that lets a coding agent (Claude Code / Codex / any MCP client) triage your inbox end to end: read & mask email → upsert calendar events → draft replies → post a digest to Slack — all driven by your own Google + Slack credentials.

Every email body, header and snippet is run through a local masking pipeline before it ever reaches the model: secrets are irreversibly redacted, contact PII is swapped for reversible tokens, and only the human-facing write paths (calendar / Slack / reply draft) restore the real values. Names go to your own model; passwords, API keys and card numbers never come back at all.

Gmail ──► [ mask ] ──► agent reasons over safe text ──► Calendar (upsert)
                                                    ├──► Gmail reply DRAFT (never sent)
                                                    └──► Slack digest (one per run)

Features

• Unified tools with service prefixes: gmail_* (search / read / label / reply-draft), calendar_* (idempotent upsert + list), slack_* (post a report).

• Masking-first: a Gitleaks-style secret pass → allowlist → PII tokenizer → in-memory vault, all in-process. See docs/masking.md.

• Idempotent calendar upserts keyed by iCalUID, so re-running never double-books. Timed, all-day and multi-day events supported.

• Reply drafts only — a threaded draft syncs to your mail client; the server never sends.

• Apple Mail deep-links (message://) so a digest line opens the original mail.

• Configurable calendar routing — define any number of categories via GOOGLE_CALENDAR_ID_<KEY> environment variables; nothing is hardcoded.

• No telemetry, no external services beyond Google + Slack. Secrets stay in a local, gitignored env file.

Related MCP server: Google MCP Server

How it works

The server is stateless transport over the Google + Slack APIs plus the masking layer. It is meant to be registered with an interactive agent and driven by a prompt (e.g. a daily inbox-triage routine). Scheduling that prompt is left to you or your automation daemon — this repo ships the tools, not a scheduler. See docs/operating-handoff.md.

Requirements

• Python ≥ 3.13, managed with uv

• A Google OAuth Desktop-app credential.json with the Gmail API + Calendar API enabled (scopes gmail.modify + calendar)

• A Slack Bot User OAuth token (xoxb-…) with chat:write, invited to your target channel

• (optional) presidio-analyzer + a spaCy model for full PERSON/LOCATION NER

Quick start

# 1. install
uv sync                      # add `--extra nlp` for Presidio (English-only) PERSON/LOCATION masking; names are unmasked by default

# 2. configure (secrets live OUTSIDE the repo)
cp .env.example ~/.config/inbox-mcp/.env
chmod 600 ~/.config/inbox-mcp/.env
$EDITOR ~/.config/inbox-mcp/.env          # paths, Slack token, calendar IDs

# 3. run the server (first run opens a browser for Google consent → token.json)
uv run inbox-mcp

# 4. tests
uv run pytest -q

Register with an agent

Point the agent at this directory; no secrets go in the registration (the server loads them from ~/.config/inbox-mcp/.env):

claude mcp add inbox_mcp -- uv run --directory /path/to/inbox-mcp inbox-mcp
# or
codex mcp add inbox_mcp -- uv run --directory /path/to/inbox-mcp inbox-mcp

Documentation

Security

• Secrets (credential.json, token.json, .env) are gitignored and belong in ~/.config/inbox-mcp/ (chmod 600) — never in the repo or agent config.

• Masking runs before any email content reaches the model; secrets are redacted irreversibly and never restored.

• Reply drafts are never auto-sent.

• Calendar writes target secondary calendars you configure, not your primary.

License

MIT.

Contributing

See CONTRIBUTING.md.