@mnicole-dev/calcom-mcp-server

create-booking

Create a new booking by providing event type ID, start time, attendee details, and timezone. Add optional notes, guests, location, or custom meeting URL.

Instructions

Create a new booking.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "eventTypeId": "<eventTypeId>",
      "start": "<start>",
      "attendeeName": "<attendeeName>",
      "attendeeEmail": "<attendeeEmail>",
      "attendeeTimeZone": "<attendeeTimeZone>"
    },
    "name": "create-booking"
  }
}

Input Schema

Name	Required	Description
`notes`	No	Additional notes for the booking
`start`	Yes	ISO 8601 start datetime
`guests`	No	Additional guest email addresses
`location`	No	Meeting location
`meetingUrl`	No	Custom meeting URL
`eventTypeId`	Yes	The event type ID to book
`attendeeName`	Yes	Attendee full name
`attendeeEmail`	Yes	Attendee email address
`attendeeTimeZone`	Yes	Attendee timezone (e.g. America/New_York)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 30, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states that a booking is created, but does not disclose side effects like availability validation, attendee notifications, duplicate handling, permissions, or idempotency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

One short sentence with no filler, and the key verb is front-loaded. It is concise, but that conciseness comes at the cost of behavioral and contextual information scored elsewhere.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no annotations, no output schema, 9 total parameters, and 5 required parameters, a one-sentence purpose is insufficient. The description omits prerequisites, side effects, validation behavior, and return value expectations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters. The description adds no parameter-level meaning and does not clarify relationships between parameters like eventTypeId, start, or attendee fields.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description uses 'Create' as a specific verb and 'booking' as a resource, making the action unambiguous. It distinguishes from siblings like cancel-booking, reschedule-booking, and get-booking by indicating a new booking, though it adds little beyond the tool name.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no explicit guidance on when to use this tool versus alternatives. It doesn't mention prerequisites such as checking availability or referencing a valid event type, and the word 'new' only implicitly suggests creation rather than modification.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.