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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the read-only nature is covered. The description adds a bit of behavioral context by clarifying that the tool returns recurring slots per day, but it does not disclose additional traits such as timezone behavior, how overrides are handled, or whether booked appointments affect the schedule. With annotations present, this is adequate but not rich.

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 a single, concise sentence with no wasted words. It front-loads the action and resource, and the parenthetical adds necessary clarification without becoming verbose. Every word contributes to understanding the tool's purpose.

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 tool is simple, has one well-documented parameter, and benefits from strong annotations (readOnly, idempotent, openWorld). The description conveys the core returned concept—recurring slots for each day—but it does not explain the exact output structure or edge cases like how overrides are reflected. This is slightly incomplete, but for selecting and invoking the tool it is sufficient.

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 100% and the only parameter, calendarId, is clearly described as 'The calendar ID.' The description does not add any additional meaning or usage detail for this parameter. Since the schema fully documents the parameter, the baseline 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 clearly states a specific verb and resource: 'Get the weekly availability schedule for a calendar.' The parenthetical '(recurring slots for each day of the week)' adds a precise scope and distinguishes it from sibling tools like get_calendar_availability, which likely covers one-off availability rather than recurring weekly slots.

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 provides no explicit guidance on when to use this tool versus alternatives. It does not mention when weekly recurring availability is needed instead of one-off availability, nor does it reference sibling tools such as get_calendar_availability or get_calendar_overrides. Usage context must be inferred entirely from the tool name and the parenthetical.

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