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

With no annotations, the description carries the full burden. It usefully discloses the side-effect profile (no booking created, no card data accepted) and that values prefill on the page. It says nothing about scope (no property parameter is passed, so how the target property is determined is unstated) or about failure modes when dates are invalid or exceed the 30-night cap.

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 tightly written sentences, front-loaded with the core action and followed by the two most decision-relevant caveats. The only weak element is the dangling mention of 'currency', which has no corresponding parameter and slightly muddies an otherwise clean statement.

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 6-parameter read-only URL builder with no annotations and no output schema, the description covers the essentials: what is produced, what it does not do, and that inputs prefill. Missing is any note on how the property/booking page is scoped and whether the returned link expires, but the schema fully carries the parameter detail.

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 schema already documents every parameter in detail (date format, Pacific/Auckland interpretation, occupancy rules, the room_type caveat). The description's 'Dates, guests and currency prefill' adds framing but no syntax or constraints beyond the schema, and it introduces 'currency', which is not a parameter at all. Baseline 3 is correct.

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: it builds a Channex booking-page URL for the guest to open. The negative clause ('Does not create a booking and does not accept payment card data') sharply separates it from any booking-creation tool. It never names or contrasts with its actual siblings (check_availability, get_property_info), so it stops short of full sibling differentiation.

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 exclusion of booking creation and payment handling implies this is a pre-booking, hand-off step, but there is no explicit statement of when to prefer it over check_availability or get_property_info. A capable agent can infer the ordering (check availability, then produce the link), but it must infer it rather than read it.

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