calendar_find_availability

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

The description explicitly states a meaningful behavior: 'Returns no slots if any required calendar is unknown.' This goes beyond the readOnlyHint annotation to explain a failure mode. It does not contradict the annotations.

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 redundant words. It packs all essential information efficiently.

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?

While the core purpose and a failure mode are described, the description does not outline the structure of a successful response (e.g., list of time ranges with start/end). Since there is no output schema, this omission leaves some ambiguity about expected return data.

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 description adds semantic meaning to several parameters: 'durationMinutes' is clarified by 'at least durationMinutes', 'timeMin/timeMax' are scoped to 'within a 31-day window', and 'calendars' is defined as 'explicit account/calendar pairs'. This enriches the schema which only provides field names and types.

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 the tool's action ('Find maximal common-free ranges'), the resource ('across explicit account/calendar pairs'), and key constraints ('at least durationMinutes', 'within a 31-day window'). This unambiguously differentiates it from other calendar tools.

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 a specific use case (finding overlapping availability across multiple calendars) without explicitly naming alternatives. The mention of 'explicit account/calendar pairs' and the 31-day window provides enough context for an agent to choose this over other calendar tools, though it could be more explicit about when not to use it.

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