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

Annotations already declare this a non-destructive, non-open-world read. The description adds genuinely new behavioral context on top: slots are booked in the agency's timezone, meetings are 30 minutes on weekdays, and—most importantly—a returned slot does not reserve anything until a booking link is confirmed.

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?

Three tight sentences: resource first, return payload second, safety caveat last. Nothing is padding and the most important constraint (a slot is not a booking) lands where it will be read.

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 steps in and names the return fields (start, end, readable label), and it covers timezone and meeting-length semantics. It omits edge cases such as an empty result set or how many slots come back, which is the only visible gap for a two-parameter read tool.

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% and both parameters (daysAhead, durationMinutes) are fully documented there, so the baseline is 3. The description's mention of 30-minute weekday meetings loosely reinforces durationMinutes but adds no syntax, units, or defaults beyond the schema.

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 and resource—real open slots from the agency's appointment calendar—and pins down the shape of those slots (30-minute, weekday, agency timezone). It also explicitly separates itself from create_booking_link, so an agent can tell the two apart without opening either 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?

The closing sentence routes the agent to the correct alternative and states the condition that selects it: a slot is not a booking, so hand the human a create_booking_link. It stops short of saying when the tool should not be called at all, but the practical next-step guidance is explicit.

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