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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real behavioral context: the exact return payload (description, FAQ, hours, photos with credits, booking links), the affiliate:true flag semantics, and the NOT_FOUND failure mode. It duplicates 'Read-only' from the annotations but goes well beyond them.

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?

A single dense sentence block front-loaded with the read-only and resource statement, then progressively narrower detail. Every clause carries information; only the restated 'Read-only' is redundant given the annotations.

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 an output schema present the description need not enumerate return values, yet it usefully summarizes them, and annotations cover the safety profile. The notable gap is the three optional parameters, whose role in a by-id lookup is never explained.

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 only 25% – just the id field is documented. The description mentions 'by id' and the affiliate flag, but says nothing about adults, check_in, or check_out, leaving three query parameters (presumably for availability/pricing) unexplained in both the schema and the description.

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 with scope: 'Full details for one BangkokVacay listing by id.' The 'by id' framing plus the id parameter's note that it comes 'from search_listings' distinguishes this from search_listings, though the description itself never names the sibling.

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 implied rather than stated: fetch by id after searching, and the id source is given in the schema. There is no explicit when-to-use/when-not statement or named alternative for retrieving multiple or filtered listings.

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