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

With no annotations, the description carries the full burden and does disclose the return shape: prices are in euro cents and each extra carries a billing unit (per_stay, per_night, per_person_night). It does not mention any auth/permission needs, but for a zero-parameter read-only listing tool those gaps are minor.

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 sentences, both front-loaded: scope and examples first, the breakfast carve-out second. Every clause (examples, price unit, billing units, sibling pointer) adds actionable information with no filler.

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, so the description must explain what comes back, and it does (extras, euro-cent prices, billing units). Combined with the routing note to hotel_info, an agent has everything needed to call this tool correctly with zero parameters.

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 tool takes no parameters, so the baseline is 4. The description compensates by enumerating the billing-unit values returned, which is the closest thing to input semantics here.

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 (List) plus resource (paid extras bookable at Yasha Hotel) and grounds it with concrete examples (late check-out, parking, baby bed). It also explicitly distinguishes the breakfast option as belonging elsewhere, so an agent can tell list_extras apart from hotel_info without reading 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?

Names the condition that selects a sibling: buffet breakfast is a separate per-guest-per-night option available via hotel_info. That is clear routing for one case, but there is no general statement of when to call list_extras versus get_price_calendar or list_rooms.

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