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

Annotations only say it is not read-only and not destructive; the description adds the consequential facts: no money moves, but a REAL appointment is placed and the person's name and phone are handed to the shop, and no confirmation SMS is sent from this path. These are precisely the side effects and user-communication constraints an agent cannot infer from structured fields.

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?

Front-loaded with the highest-stakes fact (a real appointment is placed) and the hard precondition. The bilingual English/Korean duplication roughly doubles the length, which is defensible for a bilingual context but is redundancy for a single-language reader.

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?

For a mutation tool with no output schema, the description covers preconditions, side effects, and communication caveats thoroughly. Its one gap is that it never indicates what the call returns (e.g., a reservation/booking id) for follow-up, which matters for an irreducible write operation.

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%, so the baseline is 3, but the description goes beyond the schema by explaining the semantic gate on user_confirmed (only set true after confirmation) and the provenance requirement for starts_at and staff (values from booking_availability, unchanged). It adds real meaning rather than restating 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 ('Create a real reservation') and even names the underlying action (action=booking.reserve). It is clearly distinguishable from siblings like booking_availability and booking_menu, which are read/lookup tools. An agent knows exactly what this tool does without opening the 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?

It supplies the key precondition (only call with user_confirmed=true after the person confirmed date, time, staff and service) and ties two parameters to an upstream sibling ('starts_at and staff MUST be values returned by booking_availability'). It does not explicitly route the agent to the alternative tool for merely checking slots, so the when-not story is implied rather than stated.

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