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

The readOnlyHint annotation already covers the safety profile, so the description is not required to restate that. The description does add useful behavioral context by listing what the full listing includes, and it implies a single-listing fetch. It does not mention potential pagination, rate limits, or auth requirements, but for a simple read-only fetch this is a minor gap.

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 concise fragment with no filler and is front-loaded with the key word 'Full listing'. The enumeration of included fields earns its place. It is slightly telegraphic and could include more explicit framing, but it is appropriately short.

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 id parameter and a readOnlyHint annotation. There is no output schema, so the description's list of returned fields partially compensates. However, it omits the meaning of the id parameter and provides no guidance on when to use this tool versus sibling listing tools, leaving the agent to infer important invocation context.

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 has one required 'id' parameter with 0% description coverage, and the description never mentions the id parameter or explains that it is the listing identifier. The agent must infer this from the tool name and property name, which is not reliable. With low schema coverage, the description should compensate but does not.

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 identifies the resource as a listing and enumerates the specific content returned (input_schema, examples, SLA, payment timing, seller), making it clear this is a detail-fetch tool rather than a search or mutation. It lacks an explicit verb like 'retrieves', and it does not explicitly contrast with siblings, but the title plus 'Full listing' make the purpose reasonably clear.

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 provides no 'when to use' guidance and no comparison with alternatives such as search_listings, my_listings, or update_listing. It does not state that this tool should be used when you already have a specific listing id. The usefulness is implied by the tool name and output contents, but there is no explicit usage context.

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