facebook_marketplace_item

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

With no annotations provided, the description carries the behavioral burden and usefully discloses that only public data is returned, no Facebook account is required, and specific fields like seller and approximate coordinates are exposed. It does not describe error behavior for removed or private listings, rate limits, or whether returned fields may be missing.

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 definition is two short sentences, front-loaded with the purpose and then the access condition. The list of returned fields is compact and every phrase adds useful 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?

For a one-parameter read-only detail lookup with no output schema, the description supplies the important returned fields and the no-account access condition. It leaves minor gaps around item_id semantics and error handling, but covers the core call adequately.

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 single required item_id parameter is defined in the schema with a pattern and a brief description, but the tool description itself adds no meaning about the parameter's format or source. Because schema description coverage is reported as 0%, the description does not compensate for that gap.

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 states a specific verb and resource: "Get public Marketplace listing detail," and names returned fields such as photo URLs, seller, and approximate coordinates. It is distinguishable from search-style siblings by being a detail lookup for one listing, though it does not explicitly name facebook_marketplace_search.

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 phrase "listing detail" and the item_id schema imply this is used after finding a specific listing, and "No Facebook account needed" gives an access condition. However, it does not explicitly say when to use this instead of facebook_marketplace_search or what to do if the listing ID is unavailable.

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