What is VibeMCP?
VibeMCP is a Token-Optimized Unified MCP Server for Gmail and Microsoft 365. It connects your AI assistant to your email and calendar accounts while using up to 51% fewer tokens than traditional JSON-based MCP servers.
The Problem
Most email and calendar MCP servers return verbose JSON:
json
[
{"id": "abc123", "subject": "Meeting Tomorrow", "from": "john@example.com", "date": "2025-12-18", "snippet": "Let's meet at 3pm..."},
{"id": "def456", "subject": "Q4 Report", "from": "jane@example.com", "date": "2025-12-17", "snippet": "Please review the..."}
]~85 tokens for 2 messages. Repeated keys eat tokens on every row.
The Solution
VibeMCP uses TOON (Token-Oriented Object Notation) -- an open format that declares the schema once, then streams data as tab-delimited rows:
messages[2]{id,subject,from,date,snippet}
abc123 Meeting Tomorrow john@example.com 2025-12-18 Let's meet at 3pm...
def456 Q4 Report jane@example.com 2025-12-17 Please review the...~38 tokens for the same data. No repeated keys, no brackets, no quotes.
Key Features
- 31 tools across Gmail, Outlook, Google Calendar, and Outlook Calendar
- TOON output with per-call
formatparameter (switch to JSON anytime) - Multi-account -- connect multiple Google and Microsoft accounts
- Cross-account search, unified inbox, and merged calendar
- Self-hosted -- no telemetry, no data retention, fully local
Comparison
| Feature | VibeMCP | gmail-mcp | ms-365-mcp-server |
|---|---|---|---|
| Gmail | 8 tools | 60+ tools | - |
| Outlook Mail | 8 tools | - | 90+ tools |
| Unified (both) | Yes | No | No |
| TOON output | Yes | No | No |
| Multi-account | Native | No | No |
| Token savings | 51% | None | None |
Existing TOON MCP servers (like toon-mcp) are generic JSON-to-TOON converters. VibeMCP encodes at the source level, selecting optimal fields per data type.
Next Steps
- Getting Started -- install and authenticate in 5 minutes
- TOON Format -- how the token optimization works
- Tools Reference -- all 31 tools documented