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

With no annotations supplied, the description does carry real weight here and adds genuine value by disclosing the authentication requirement (valid Druk Asia API key, injected automatically via the x-api-key header). It does not say what happens when the reference is invalid or not found, nor whether the lookup is read-only and side-effect free, so behavior on failure remains undisclosed.

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 load-bearing, with the core action front-loaded and the auth caveat second. Nothing is redundant or 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?

The tool is simple (one required string parameter, no nesting), and the auth requirement is covered, which suits a definition this short. However, with no output schema present, the description gives an agent no indication of what a returned booking contains or how a missing reference is surfaced, leaving a real gap for a retrieval tool.

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 parameter already carries an example format (DA-26-X7K2PQ), so the schema does the heavy lifting. The description only restates that the parameter is a booking reference, adding no syntax, casing, or validation meaning beyond 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 plus the lookup key: "Retrieves a booking by its booking reference." That clearly separates it from create_booking, update_booking, and the list_* siblings, though it never names a sibling explicitly.

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?

Usage is only implied: an agent can infer it should call this when it already holds a booking reference. There is no explicit statement of when to prefer get_itinerary or list_endpoints instead, and no preconditions or exclusions beyond the auth note.

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