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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds real behavioral context beyond that: the exact payload contents (invoice items, info items, additional guests) and that cancelled bookings are still retrievable, which the agent can't infer from the schema or annotations.

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 short sentences, front-loaded with the core action, followed by payload scope, status applicability, and an endpoint reference. Every sentence carries information and nothing is padded.

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?

With no output schema, the description compensates by enumerating the returned components, and with only one fully documented parameter there are no gaps an agent needs filled before calling. Nothing essential is missing for a single-record read.

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 bookingId parameter is fully documented in the schema, so the description's 'by id' adds no syntax or format information. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Fetch one booking by id') and immediately scopes the payload to a single record with its invoice items, info items and additional guests. This distinguishes it from list-style siblings like beds24_list_bookings and beds24_get_unit_bookings, which return collections.

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?

'Works for any status, including cancelled' gives a useful usage nuance, and 'by id' implies the caller already has an identifier. However, no alternative tools are named (e.g., when to prefer beds24_list_bookings or beds24_update_booking), so the when-to-use guidance remains implied rather than explicit.

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