Schedule a new Google Calendar event with summary, start/end, optional location, description, and attendees. Adding attendees emails them immediately, so confirm the list first.
Create an event. Adding attendees emails them immediately, so confirm the list before calling with any.
| Name | Required | Description | Default |
|---|---|---|---|
| end | Yes | RFC3339 | |
| start | Yes | RFC3339 | |
| summary | Yes | ||
| location | No | ||
| attendees | No | ||
| calendarId | No | primary | |
| description | No |
Changes observed during successful MCP inspections.
v0.2.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Discloses a significant non-obvious side effect beyond the annotations: adding attendees imediately sends emails, and advises confirming before calling. Annotations only indicate readOnly=false/destructiv=false and do not capture the external notification behavior, so this adds real value.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, with the core purpose first and the critical warning second. Every word earns its place and there is no filler or repetition of schema details.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers the essential usage and the most important side effect, but with no output schema and no mention of what the tool returns (e.g., an event id needed for later update/delete), the agent is left to infer some post-call behavior. Adequate but with clear gaps.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description adds meaning for attendees by explaining that including them triggers emails. However, schema coverage is only 29% across 7 parameters, and the description compensates for only this one parameter; summary, calendarId, location, and description are largely left to inference.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a precise action ('Create an event') and the verb 'create' clearly distinguishes it from update/delete/list calendar siblings. It is clear, but adds no scope details (e.g., default calendar or what fields are required beyond the schema), so it falls just short of a 5.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Tells the agent when to use it (to create an event) and provides an important pre-condition: confirm the attendee list before calling because attendees are imediately emailed. It does not explicitly name alternatives, but no sibling tool duplicates the creation action, so the guidance is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.