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

Annotations already declare readOnly/idempotent/non-destructive, so the description adds real value instead of repeating safety hints: it scopes the payload ('No host contact details') and gives an interpretation rule that changes agent reasoning ('An amenity not listed has not been stated: it is unknown, not absent'). With no output schema, it also carries the return-content burden, though it says nothing about errors for an invalid or non-existent listing_id.

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?

Front-loaded with the returned-field inventory, then a second block for amenity semantics; nearly every clause carries information. The amenity sentence is dense and slightly overstuffed ('English code, the value and the sentence... applies_to'), but nothing is padding.

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 read-only, two-parameter tool with no output schema, the description covers returned fields, a scope exclusion, and the non-obvious amenity interpretation rule. It lacks only failure behavior (invalid/missing listing_id) and any note on whether the response is cached or translated at read time.

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%, so a 3 is the baseline, but the description adds meaning the schema does not: it explains that 'language' governs the language of the sentence shown on the listing page, not just labels, and clarifies applies_to semantics for amenities. That is genuine added semantic value over the enum and default text.

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 ('Public details of one Roraima listing') and then enumerates exactly which fields come back (name, description, town, stay rules, cancellation policy, amenities, page link). The singular scope plus the 'listing_id from search_listings' reference makes it clearly distinguishable from search_listings without opening either schema.

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: the singular 'one listing' plus the listing_id reference to search_listings suggests the follow-up-detail workflow, but the description never says when to call this versus search_listings or get_product, nor states any precondition. No exclusions or alternatives are given.

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