create_calendar_event

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

With no annotations at all, the description carries the full burden, and it does disclose the single most consequential behavior: attendees are silently added unless send_invitations is true. That is genuinely useful side-effect disclosure, but it says nothing about permissions/scopes required, what happens on duplicate or conflicting events, or what the tool returns on success.

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?

Three short sentences, no filler, and the highest-risk behavior is placed where it will be read. Every sentence carries a distinct instruction or disclosure.

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?

For an 11-parameter write tool with no annotations and no output schema, the description covers the interaction protocol and the invitation side effect but omits conflict handling, required permissions, and confirmation of what is returned. It is adequate to call the tool correctly but not complete for a mutation of this surface area.

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?

Schema coverage is 64%, so the schema already explains start format, time_zone, calendar, days, and duration defaults. The description adds real semantic value for send_invitations and attendees by explaining the silent-add default, which the schema only hints at. The remaining parameters (title, location, description, all_day) are self-evident, so the baseline of 3 fits.

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?

The description opens with a specific verb and resource ("Create an event"), which cleanly separates it from the read-oriented siblings list_calendars and find_calendar_events. It does not explicitly contrast itself with update_calendar_event, but the create/update distinction is obvious enough that an agent can route without ambiguity.

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?

It gives one concrete procedural rule ("Confirm title, time and time zone with the user first") and a conditional for invitations, which is real usage guidance rather than none. However, it never states when to use this versus update_calendar_event or what to do when an event may already exist, leaving the sibling comparison to inference.

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