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

The destructiveHint annotation already tells the agent this is a mutating write, lowering the bar. The description adds useful context with "Times are 24-hour GMT" and the draft/unpublished staging semantics. It stays silent on side effects an agent would care about, such as whether invites are dispatched or what permissions/API scope are needed.

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 compact sentences with the purpose front-loaded, followed by format and staging guidance. The trailing "Elvanto: calendar/events/create" API path is minor redundancy but the text is otherwise dense and waste-free.

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 a 19-parameter mutation with no output schema and only a destructiveHint annotation, the description is thin: it never flags the required set, the repeat_frequency dependency for daily/monthly/yearly repeats, or what a successful call returns. The 100% schema coverage compensates for most of the per-parameter gap, leaving this merely adequate.

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 description coverage is 100%, so all 19 parameters are documented in the schema itself, making 3 the baseline. The description only restates the GMT time format and the repeating option, adding essentially nothing beyond what the schema already conveys.

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 specific verb and resource ("Create an event on a calendar") and adds the repeat capability, so an agent immediately knows this is the write counterpart to elvanto_list_calendar_events. It does not explicitly name the sibling, but the create/list split is unambiguous from the verb alone.

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?

Gives one concrete usage hint — use status "draft" to stage an event unpublished — which is genuine operational guidance. Beyond that there is no when-to-use vs. alternatives framing, no prerequisites (e.g. needing a calendar_id from elvanto_list_calendars), and no exclusions.

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