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

The description discloses the return shape (title, times in the user's zone, countdown, location, attendees, id) and the selection behavior (not-yet-started, 366-day horizon, calendar scope). The annotations are all false and add little safety context, but the description itself makes the read-like nature apparent.

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?

The description is two concise sentences with no filler. It front-loads the selection rule before listing the returned fields, and every phrase earns its place.

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 tool with one optional parameter and no output schema, the description provides both the selection criteria and the fields an agent should expect in the result. Minor unspecified edge cases, such as what happens if no event exists in the window, do not materially undermine completeness.

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 only parameter, calendar, is already fully described in the schema as 'One calendar name; default every imported calendar.' The description mostly mirrors this semantics, so it adds little beyond what the schema already provides.

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 specifies exactly what the tool does: it returns the first event that has not yet started within a 366-day window, across all imported calendars or a named one. This clearly distinguishes it from sibling list/search tools, which are not limited to the single next upcoming event.

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?

The description clearly conveys the use case: retrieve the next upcoming event, optionally scoped to a specific calendar. It does not explicitly say when to prefer events_list or events_search instead, so it stops short of providing full when/when-not guidance.

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