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

No annotations are provided, so the description carries the burden. It usefully discloses recurrence expansion, newest-first ordering, and default window/calendar behavior. It does not explicitly state that the operation is read-only/side-effect-free or describe pagination/rate limits, but for a list tool the provided behavior is reasonably helpful.

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 three sentences with no filler. The main action is front-loaded, and each sentence adds value: listing behavior, recurrence handling, and default scope. It is compact while still communicating the most important behavioral details.

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?

The description is complete for a straightforward listing tool: it covers scope, ordering, recurrence, defaults, and calendar selection via the schema. There is no output schema, so the exact returned event fields are not specified, but this is a minor gap for a list operation. Overall, an agent can invoke it correctly with the provided information.

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 the schema already documents all five parameters including defaults, ISO 8601 format, mailbox format, and the limit cap. The description adds no per-parameter semantics beyond what the schema already provides, so the baseline score of 3 is appropriate.

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 uses a specific verb and resource: 'List events in a time window, newest first.' It adds meaningful behavioral detail about recurrence expansion, which clearly distinguishes it from sibling search and listing tools. The purpose is immediately understandable and unambiguous.

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 implies usage: list all events in a given time window, possibly for a default calendar. However, it does not explicitly name alternatives like search_google_calendar_events or find_google_calendar_busy_times, nor does it state when this tool should not be used. The guidance is adequate but mostly implicit.

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