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

Beyond readOnlyHint, it discloses that results exclude cancelled events, that per-account `errors` are returned, that a short page does not prove completeness, and that an account reconnect hint requires action. These are operationally important behaviors an agent could not infer from the schema.

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?

Information is front-loaded with scope first, then window, filters, return shape, and pagination. It is dense but nearly every clause earns its place; the trailing Japanese reconnect instruction is useful but slightly awkward in the flow.

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?

With no output schema, the description still covers return contents (non-cancelled events, per-account errors), pagination signals (has_more, next_page_tokens), and error handling (reconnect hint). An agent has enough to call and page correctly.

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 already 100%, so baseline is 3; the description adds value by explaining that q is a free-text filter, that ISO time_min/time_max or `days` control the window, and that show_hidden_invitations defaults to false. It supplies interpretation and defaulting intent rather than merely restating field names.

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+resource ('List/search the user's Google Calendar events') plus scope ('across ALL calendar-capable connected accounts, merged and sorted by start time'). An agent can distinguish it from get_event, list_calendars, and get_free_busy without opening any schema.

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 the default window (today + 7 days) and explicit pagination procedure ('pass next_page_tokens as page_tokens, reuse the returned time_min/time_max and the same filters'). It does not explicitly name when to prefer get_event or list_calendars instead, so it stops short of full alternative routing.

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