Connect
Optimize
Secure
Cal.com MCP Server
for AI Agents
Production-ready Cal.com MCP server with 52 extensible actions — plus built-in authentication, security, and optimized execution.
Cal.com MCP Server
Built by 
StackOne
StackOne 
Coverage
52 Agent Actions
Create, read, update, and delete across Cal.com — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Cal.com MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Cal.com tool response scanned for prompt injection in milliseconds — 88.7% accuracy, all running on CPU.
Prompt Injection Defense →
Performance
Max Agent Context. Min Cost.
Free up to 96% of your agent's context window to enhance reasoning and reduce cost, on every Cal.com call.
Tools Discovery →What is the Cal.com MCP Server?
A Cal.com MCP server lets AI agents read and write Cal.com data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Cal.com MCP server ships with 52 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, and optimized agent context. Connect it from MCP clients like Claude Desktop, Cursor, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.
All Cal.com MCP Tools and Actions
Every action from Cal.com's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Current Users
- Get Current User
Get information about the currently authenticated user
- Update Current User
Update the authenticated user's profile
Bookings
- Create Booking
Create a new booking
- List Bookings
Get all bookings for the authenticated user
- Get Booking
Get information about a specific booking
Booking Attendees
- Add Booking Attendee
Add an attendee to an existing booking
- Get Booking Attendees
Get all attendees for a booking
- Get Booking Attendee
Get a specific attendee for a booking
Event Types
- Create Event Type
Create a new event type
- List Event Types
Get all event types for the authenticated user
- Get Event Type
Get information about a specific event type
- Update Event Type
Update an existing event type
- Delete Event Type
Delete an event type
Schedules
- Create Schedule
Create a new availability schedule
- List Schedules
Get all schedules for the authenticated user
- Get Schedule
Get information about a specific schedule
- Update Schedule
Update an existing schedule
- Delete Schedule
Delete a schedule
Reserved Slots
- Get Reserved Slot
Get details of a reserved slot
- Update Reserved Slot
Update a reserved slot
- Delete Reserved Slot
Delete a slot reservation
Teams
- Create Team
Create a new team
- List Teams
Get all teams accessible to the authenticated user
- Get Team
Get information about a specific team
Out Of Office Entrys
- Create Out Of Office Entry
Create a new out of office entry
- Update Out Of Office Entry
Update an existing out of office entry
- Delete Out Of Office Entry
Delete an out of office entry
Webhooks
- Create Webhook
Create a new webhook
- List Webhooks
Get all webhooks for the authenticated user
- Get Webhook
Get details of a specific webhook
- Update Webhook
Update an existing webhook
- Delete Webhook
Delete a webhook
Default Conferencing Apps
- Get Default Conferencing App
Get the default conferencing application
- Set Default Conferencing App
Set the default conferencing application
Other (18)
- Add Booking Guests
Add guests to an existing booking
- Get Default Schedule
Get the default schedule for the authenticated user
- Get Available Slots
Get available time slots for an event type
- List Calendars
Get all connected calendars
- Get Calendar OAuth URL
Get OAuth URL to connect a calendar
- List Out Of Office Entries
Get all out of office entries for the authenticated user
- List Conferencing Apps
Get all connected conferencing applications
- Get Conferencing OAuth URL
Get OAuth URL to connect a conferencing app
- Get Stripe Connect URL
Get URL to connect Stripe account
- Cancel Booking
Cancel an existing booking
- Reschedule Booking
Reschedule an existing booking to a new time
- Confirm Booking
Confirm a pending booking
- Decline Booking
Decline a pending booking request
- Reserve Slot
Reserve a time slot temporarily
- Check Calendar Connection
Check a calendar connection status
- Disconnect Calendar
Disconnect a calendar integration
- Connect Conferencing App
Connect a conferencing application
- Disconnect Conferencing App
Disconnect a conferencing application
Set Up Your Cal.com MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Cal.com in under 10 lines of code.
MCP Clients
Agent Frameworks
JSON{
"mcpServers": {
"stackone": {
"command": "npx",
"args": [
"-y",
"mcp-remote@latest",
"https://api.stackone.com/mcp?x-account-id=<account_id>",
"--header",
"Authorization: Basic <YOUR_BASE64_TOKEN>"
]
}
}
}More Calendar & Scheduling MCP Servers
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Cal.com MCP Server Resources
MCP Code Mode: Keeping Tool Responses Out of Agent Context
Anthropic's code_execution processes data already in context. Custom MCP code mode keeps raw tool responses in a sandbox. 14K tokens vs 500.
11 min
Comparing BM25, TF-IDF, and Hybrid Search for MCP Tool Discovery
Benchmarking BM25, TF-IDF, and hybrid search for MCP tool discovery across 916 tools. The 80/20 TF-IDF/BM25 hybrid hits 21% Top-1 accuracy in under 1ms.
10 min
Indirect Prompt Injection Defense for MCP Tools: A Technical Guide
MCP tools that read emails, CRM records, and tickets are indirect prompt injection vectors. Here's how we built a two-tier defense that scans tool results in ~11ms.
12 min
Cal.com MCP Server FAQ
Cal.com MCP server vs direct API integration — what's the difference?
A Cal.com MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Cal.com. A Cal.com MCP server is for AI agents — MCP clients like Claude and Cursor, plus framework agents built with OpenAI, LangChain, or Vercel AI — discovering and calling Cal.com at runtime. StackOne provides both.
How does Cal.com authentication work for AI agents?
Cal.com authentication for AI agents works through a StackOne Connect Session. Create one via the dashboard or the SDK — you get an auth link and ready-to-paste config for Claude Desktop, Cursor, and other MCP clients. Your user authenticates their own Cal.com account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Cal.com MCP tools vulnerable to prompt injection?
Yes — Cal.com MCP tools can be vulnerable to indirect prompt injection. Any tool that reads user-written content — documents, messages, tickets, records, or free-text fields — is a potential vector. StackOne Defender scans every tool response before it enters the agent's context — regex patterns in ~1ms, then a MiniLM classifier in ~4ms. 88.7% accuracy, CPU-only.
What is the context bloat of a Cal.com agent and how do I avoid it?
Context bloat happens when Cal.com tool schemas and API responses eat your Cal.com agent's memory, preventing it from reasoning effectively. A single Cal.com query can return a massive JSON response, and connecting multiple tools compounds the problem. Tools Discovery and Code Mode reduce context bloat — loading only relevant tools per query and keeping raw responses out of the agent's context.
Can I limit which actions my Cal.com agent can access?
Yes — you can limit which actions your Cal.com agent can access directly from the StackOne dashboard. Toggle actions on or off, or restrict them to specific accounts, with no code changes to your agent. Session tokens can be scoped to exact actions so if one leaks, exposure stays contained.
Can I create custom agent actions for my Cal.com MCP server?
Yes — you can create custom agent actions for your Cal.com MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Cal.com's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Cal.com MCP server?
Skip a Cal.com MCP server if your integration is purely software-to-software — direct Cal.com API integration is simpler when no AI agent is involved. For deterministic, compliance-critical operations (financial transactions, regulatory reporting), direct API gives you predictable behavior without agent-driven decision-making. MCP shines when AI agents need to dynamically discover and call Cal.com actions at runtime.
What AI frameworks and AI clients does the StackOne Cal.com MCP server support?
The StackOne Cal.com MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.
Put your AI agents to work
All the tools you need to build and scale AI agent integrations, with best-in-class connectivity, execution, and security.