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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds 'without hard Familia availability blockers' which hints at the blocking semantics, but it does not explain behavior like busy-hour windows or policy effects beyond what the schema already documents.

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?

Two tight sentences, with the primary usage scenario front-loaded and a useful exclusion added. No filler or repetition.

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 has 9 fully documented parameters, an output schema, and read-only annotations. The description focuses appropriately on when to use the tool, which is what an agent needs most for selection. Minor gaps like naming sibling tools or describing result shape are largely covered by other structured fields.

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 every parameter already has a meaningful description. The tool description adds no additional parameter-level insight, which is acceptable given the schema carries the full burden.

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 identifies the tool's purpose: finding free days, open dates, vacation windows, long weekends, and consecutive days without availability blockers. It also distinguishes itself by explicitly saying not to use it for listing tasks on one known date, though it does not name a specific sibling tool.

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 gives explicit trigger phrases ('find free days', 'open dates', 'vacation windows', 'long weekends') and a clear negative case ('do not use for listing tasks on one known date'). It lacks a named alternative tool, but the when/when-not guidance is strong.

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