Outlook CalendarBLOCK
A Model Context Protocol (MCP) server that allows Claude to access and manage your local Microsfot Outlook calendar (Windows only).
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
A Model Context Protocol (MCP) server that allows Claude to access and manage your local Microsoft Outlook calendar (Windows only).
[](https://opensource.org/licenses/MIT)
Features
- View Calendar Events: List events within a date range, view event details, check attendee status
- Manage Calendar Events: Create new events and meetings, update existing events
- Calendar Intelligence: Find free time slots for scheduling, identify optimal meeting times
- Multiple Calendar Support: Access different calendars in your Outlook profile
Prerequisites
- Windows operating system
- Microsoft Outlook desktop client installed
- VBScript support (see VBScript Installation below if you're on Windows 11 24H2+)
- Node.js (version 14.x or higher)
- npm (comes with Node.js)
VBScript Installation (Windows 11 24H2+ Users)
Important: Starting with Windows 11 24H2, VBScript is no longer installed by default and must be enabled as an optional feature.
If you're experiencing issues with the MCP server not working after a Windows update, you likely need to install VBScript:
- Open Settings (Windows + I)
- Go to Apps → Optional features
- Click "View features" next to "Add an optional feature"
- Search for "VBScript"
- Select VBScript and click Install
- Restart your computer after installation
VBScript Deprecation Timeline:
- Phase 1 (Late 2024+): Available as optional feature in Windows 11 24H2
- Phase 2 (~2027): Will no longer be enabled by default
- Phase 3 (Future): Complete removal from Windows
*Note: Thanks to community feedback about VBScript deprecation, I'm considering architectural improvements to make the project m
8c1e29b50c20OBSERVED · 2026-10-08Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.
claude mcp add outlook-calendar-mcp -- npx -y [email protected]
{
"mcpServers": {
"outlook-calendar-mcp": {
"command": "npx",
"args": [
"-y",
"[email protected]"
]
}
}
}Exposed tools (7)
4 read · 2 write · 1 destructive. Blast radius: 1 tool can delete or overwrite — an agent that can be talked into calling a tool can be talked into calling this one.
| Tool | Risk | Description |
|---|---|---|
create_event | write | Create a new calendar event or meeting |
delete_event | destructive | Delete a calendar event by its ID |
find_free_slots | read | Find available time slots in the calendar |
get_attendee_status | read | Check the response status of meeting attendees |
get_calendars | read | List available calendars |
list_events | read | List calendar events within a specified date range |
update_event | write | Update an existing calendar event |
Trust audit
BLOCKgrade D · trust 69/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | FAIL |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | WARN |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- declared (1 observation(s))
- Network
- none-observed
- Shell
- declared (1 observation(s))
- Dependencies
- not all pinned
- Secrets in source
- none-found
Findings (3)
exec(command, { encoding: 'utf8' }, (error, stdout, stderr) => {delete_event
@modelcontextprotocol/sdk
Gates applied: no_behavioural_pass.
8c1e29b50c20full audit observations/trust-audit/mcp-server/merajmehrabi__outlook-calendar.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-08 | 8c1e29b50c20 | BLOCK | D | 69 | first audit |
Questions
What is the Outlook Calendar MCP server?
A Model Context Protocol (MCP) server that allows Claude to access and manage your local Microsfot Outlook calendar (Windows only).
What tools does Outlook Calendar expose?
7 in total: 4 read-only, 2 that write, and 1 that can delete or overwrite (delete_event). Every one is listed on this page with its risk.
Is Outlook Calendar safe to connect to an agent?
No — not without reading the findings first. The audit graded it D (69/100) and found 1 critical or high issue in the source. Each one is listed on this page with the file and line it is on. Separately from the audit: 1 of its tools can destroy data, so scope the token you give it to what you actually need.
What credentials does Outlook Calendar need?
No credential environment variables were found in its source, so it appears to need none.
How does Outlook Calendar run?
It speaks stdio, so it runs as a local process your client starts. It is published on npm as outlook-calendar-mcp at 1.0.5.
How current is this page?
The grade is for one exact copy of the source (8c1e29b50c20), read on 2026-10-08. The repository is watched and re-audited when it changes.