reverb_listing

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

With no annotations and no output schema, the description carries the full burden and does disclose the return payload in detail. It does not cover latency, auth, or error behavior, but for a read-only single-item fetch the enumerated contents are the key behavioral disclosure and they are present.

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-loads the verb and resource, then the return contents, then the id provenance, with no filler. The middle clause is a dense list but every item is informative, so it stays tight overall.

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 single-parameter, no-output-schema fetch, the description covers purpose, the value versus search, and the full return shape, which is what the agent needs to call it correctly. It stops just short of stating prerequisites or error handling, leaving a small residual gap.

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 schema's own parameter description ('Listing id, from a search result's own listings[].id field') is essentially identical to what the description says, so the description adds no meaning beyond the structured field. Baseline 3 is correct here.

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 ('Get a Reverb listing') and then enumerates exactly what the tool returns (description, photos, policies, seller reputation). It explicitly distinguishes itself from the sibling reverb_search by noting it is 'richer than the flattened summary reverb-search returns per listing', so an agent can choose between them 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?

The comparison to reverb_search clearly implies when to reach for this tool (need full listing detail versus a search-result summary), naming the alternative explicitly. However it does not state a hard when-not-to-use rule or any prerequisites (e.g., where to obtain an id beyond search).

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