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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds substantive context the annotations cannot: there is no output schema, so enumerating the returned sections and telling the agent how to use the faq and photo fields is genuine value. Minor gaps: no error behavior for an unknown/invalid slug.

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?

One dense sentence with the core action and provenance front-loaded, and no filler. It is long and dashes-and-parentheses heavy, which makes it slightly hard to scan, but every clause carries information.

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?

A single-parameter read tool with full annotation coverage and no output schema; the description supplies the return-value inventory and the acting instructions that the absent output schema would otherwise leave unknown. Nothing needed to call it correctly is missing.

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 coverage is 100% and the slug parameter is already documented with an example, so the baseline is 3. The description goes further by stating where the slug originates (search_listings), which disambiguates it from a listing ID or free-text query.

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?

Specific verb and resource: fetch full details for a single listing by slug. It enumerates the returned facets (description, amenities, highlights, facts, capacity, faq, link, photos) and names the sibling that produces the slug (search_listings), so an agent can distinguish it from search/availability siblings without opening a 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?

It anchors usage to a workflow — the slug comes from search_listings — and gives downstream instructions for two payloads ('use them to answer questions about this listing', 'use these photos when showing it'). It does not state exclusions (e.g., that it should not be used for browsing or that check_availability/get_quote are needed for pricing).

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