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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that: it states card data is never returned (a privacy/scope constraint) and that the caller needs a Cotlet API key with access to this app (an auth prerequisite).

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 description lists the same field set twice (first 'guest, dates, rooms or beds, rate type, deposit paid, balance due and status', then again as 'guest, arrival date, nights, room type and number of people, rate type, deposit paid, balance due and status') and repeats the no-card-data point in two separate sentences. Roughly half the text is redundant, diluting an otherwise well front-loaded description.

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?

There is no output schema, so the description correctly carries the burden of describing what is returned, and it does so plus the auth requirement and the downstream workflow. It is complete for an agent to call it correctly; the redundancy is a style problem rather than a missing-information problem.

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 the single booking_ref parameter is already documented in the schema as coming from search_bookings or list_new_bookings. The description adds no syntax, format or sourcing detail beyond the schema, so the baseline 3 applies.

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?

The description states a specific verb (get/returns) and resource (one Hostelworld booking) and enumerates the fields returned, so an agent knows exactly what comes back. It implies a single-record fetch versus the sibling list/search tools but never names them explicitly, so sibling differentiation is only partial.

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 gives concrete workflow guidance: 'Use it before mark_no_show or report_payment_issue to check the status and the rate type,' naming the two sibling tools it precedes. That is clear when-to-use context; there is no explicit when-not-to-use, but for a read-only lookup tool that is a minor gap.

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