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

Annotations already declare readOnlyHint=true, so the agent knows this is safe. The description adds that it returns 'full structured details' and works by ID or slug, but does not disclose error behavior, auth requirements, or rate limits. Given the annotations cover the safety profile, this is adequate but not rich.

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?

The description is a single sentence, concise and front-loaded with the action and resource. Every word earns its place, with no fluff or repetition of schema data.

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 only one parameter, no output schema, and a read-only annotation, the description is fully self-contained. It clearly communicates what the tool does, how to identify the target listing, and what kind of response to expect ('full structured details'). No critical information 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?

The input schema already provides 100% coverage with the id parameter described as 'Public listing ID or slug.' The description adds a concrete example ('lst_abc123...') which helps clarify expected format. This goes slightly beyond the schema baseline.

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?

The description clearly states the tool's action with a specific verb ('Return'), resource ('listing'), and scope ('single listing by its public ID or slug'). It also distinguishes itself from sibling tools like search_listings and list_recent by emphasizing retrieval of a single specific listing rather than a search or list.

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?

The description implies when to use this tool: when you have a public ID or slug for a specific listing. It does not explicitly mention alternatives or exclusions, but the context is clear that this is for singular lookup. No alternative tool is named, but the intended use is unambiguous.

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