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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that: it discloses the date-omission default (today in shop timezone) and the critical constraint that only returned starts_at/staff_id values may be passed to booking_reserve (invented times rejected).

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 front-loaded English portion is tight and well ordered, but the entire message is restated in Korean, which doubles the length for an agent that reads a single language. The redundancy keeps this from being maximally concise.

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?

No output schema exists, but the description partially compensates by noting the returned fields (starts_at, staff_id) that must be forwarded. Combined with the required-parameter rule and date default, an agent has enough to call and chain the tool correctly.

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 all five parameters are already documented, including the date default and service sourcing. The description largely restates this (service required, date default) rather than adding new syntax or constraints, so it sits at the baseline.

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 ('List bookable time slots') and even names the underlying action (action=booking.availability). It is clearly distinguishable from booking_menu (source of service id) and booking_reserve (consumer of the output).

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?

Gives an explicit workflow: obtain 'service' from booking_menu first, then call this tool, then pass the results to booking_reserve. Both the prerequisite and the downstream consumer are named, so the agent knows exactly where this fits.

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