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

Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=true and openWorldHint=true, so the safety profile is supplied structurally. The description adds nothing beyond that — critically, it does not say whether this is a partial patch (omitted fields preserved) or a full replacement, which is the single most consequential behavior for an update tool.

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?

It is a single short sentence with no filler, so nothing is wasted, but the brevity reflects under-specification rather than tight editing. The most useful information is absent rather than condensed.

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 8-parameter destructive mutation with 25% schema coverage and no output schema, this description leaves significant gaps: update semantics, required-field behavior, and what a successful response contains. Annotations cover the safety profile, preventing a lower score, but the description is far from sufficient on its own.

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 only 25%: only calendar and eventUid carry inline descriptions. The description does not compensate at all — start, end, title, status, attendees and description go entirely unaddressed, including the accepted/pending/declined/cancelled status enum semantics and date/time format expectations.

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 gives a generic verb ("Change") plus a resource ("an event on the user's calendar") and a scope ("of one provider"), so an agent can infer it's a mutation on a single calendar event rather than a series or schedule. However, it never states which aspects of the event are editable, and the "one provider" phrasing is oblique rather than naming the calendar parameter.

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?

There is no when-to-use guidance, no mention of prerequisites (that the calendar id comes from list_calendars and the event uid from list_calendar_events, which appears only in the schema), and no differentiation from create_calendar_event, delete_calendar_event, get_calendar_event, or update_connection_event. The agent must infer the correct tool from name and siblings alone.

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