Chronos — agent-inbox

Local-first email and calendar inbox for AI agents. Syncs Gmail and Google Calendar into a single queryable SQLite database and exposes all data through an MCP server.

Features

• Sync multiple Gmail and Google Calendar accounts into one SQLite database
• Full-text search via FTS5 with BM25 relevance ranking (messages, events, attachment names)
• MCP server via chronos --mcp-stdio (stdio transport, no port required)
• HTTP REST API at localhost:7070 for direct queries
• Read-only SQL interface via POST /v1/query
• Optimistic event writes with provider-wins conflict resolution
• Incremental sync with historyId (Gmail) and syncToken (Calendar)
• ULID primary keys, WAL mode, no cloud dependencies at query time

Installation

pipx install chronos-mcp

Or from source:

git clone https://github.com/CourtimusPrime/chronos.git
cd chronos
pip install -e .

Setup

Run the interactive walkthrough for detailed step-by-step instructions:

chronos --walkthrough

This prints the full guide in the terminal and saves it to ~/.chronos/WALKTHROUGH.md for future reference.

Quick start

1. Google Cloud Console

• Create a project at console.cloud.google.com
• Enable Gmail API and Google Calendar API
• Configure OAuth consent screen (External, Testing mode) — add your Google account as a Test User
• Add scopes: https://mail.google.com/ and https://www.googleapis.com/auth/calendar
• Create an OAuth client ID — Application type: Web application
• Add authorized redirect URI: http://localhost:9004/callback
• Download the credentials JSON

Desktop App credentials ("installed" JSON shape) are not supported — Chronos uses the https://mail.google.com/ restricted scope, which requires a Web Application OAuth client in Testing mode.

2. Register accounts

# Stage your credentials file
chronos --use /path/to/credentials.json

# Add accounts (opens browser for OAuth consent)
chronos --add personal
chronos --add work

3. Start syncing

chronos --start

Chronos downloads all your emails and calendar events into a local SQLite database. Your AI agents query this database — no live Google API calls at read time.

4. Add the MCP server

chronos --mcp

Writes the stdio entry into .mcp.json and appends instructions to ~/.claude/CLAUDE.md.

5. Test it

claude "What's the most recent email I received?"

CLI Reference

chronos --use CREDENTIALS_PATH          # Stage a credentials JSON for --add
chronos --add ALIAS                     # Register a new account (requires prior --use)
chronos --remove ALIAS                  # Remove an account and its data
chronos --list                          # List all registered accounts
chronos --test ALIAS                    # Test account tokens
chronos --start [--http-port N]         # Start daemon (HTTP API + background sync)
chronos --stop                          # Stop the running daemon (preserves synced data)
chronos --status                        # Show sync status
chronos --sync [ALIAS] [--type full|incremental]  # Trigger sync
chronos --mcp                           # Add Chronos to .mcp.json (prompts for scope)
chronos --mcp-stdio                     # Start embedded MCP server on stdio
chronos --walkthrough                   # Print full setup guide

Ctrl+C vs --stop: Pressing Ctrl+C while chronos --start is running wipes synced data (emails, threads, events, calendars) but preserves accounts. Use chronos --stop from another terminal for a clean shutdown that preserves data.

Environment Variables

Configuration

config.yml is auto-created at ~/.chronos/config.yml on first run. The OAuth callback port is the most commonly customized setting:

settings:
  oauth:
    callback_port: 9004     # local server bind during `chronos --add`
    callback_path: /callback # appended to the redirect URI

If you change callback_port, update the Authorized redirect URI in Google Cloud Console to match.

License

MIT