@mnicole-dev/calcom-mcp-server

update-event-type

Modify an existing event type by changing its title, slug, description, duration, locations, booking fields, or visibility. Provide the event type ID and updated values.

Instructions

Update an existing event type.

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>"
    },
    "name": "update-event-type"
  }
}

Input Schema

Name	Required	Description
`slug`	No	New URL slug
`title`	No	New title
`hidden`	No	Whether the event type is hidden
`locations`	No	Updated locations
`description`	No	New description
`eventTypeId`	Yes	The event type ID to update
`bookingFields`	No	Updated booking fields
`lengthInMinutes`	No	New duration in minutes

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 only says 'Update an existing event type,' which restates the tool's obvious purpose. It does not mention whether unspecified fields are preserved or reset, whether the update is partial or full, what permissions are needed, or what the response contains.

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?

The description is a single, front-loaded sentence with no filler or repetition. It is appropriately concise for the purpose, though it is so brief that it sacrifices behavioral detail that could have been included without harming conciseness.

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?

For a mutation tool with 8 parameters, no annotations, and no output schema, the description is too thin to be complete. It gives no indication of update semantics (partial vs. full replacement), error conditions, return value, or side effects. The schema covers parameter meanings, but the behavioral context an agent needs is missing.

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 every parameter already has a clear description in the input schema. The tool description itself adds no parameter-level meaning, but the baseline of 3 applies because the schema does the heavy lifting.

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?

The description states a specific verb ('Update') and resource ('existing event type'), which clearly distinguishes it from sibling tools like create-event-type, get-event-type, and delete-event-type. It is concise and unambiguous, though it does not elaborate on which fields can be updated; that detail is left to the schema.

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 such as create-event-type or update-schedule. The wording implies mutation of an existing event type, but there are no stated conditions, prerequisites, or exclusionary notes to help an agent choose correctly among siblings.

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