search_facebook_cars

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

With no annotations, the description carries full responsibility. It discloses a key limitation: 'Best-effort: depends on Facebook not blocking the request from your IP.' However, it omits other behavioral aspects such as authentication requirements, error handling, or read-only status. The single caveat is useful but the coverage is thin.

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 compact (three sentences) and front-loads the core purpose. The caveat about blocking is placed at the end, and the technical phrase 'native, hardened through the same browser/proxy engine as carsales' adds minor noise but does not undermine clarity. Efficient 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?

The description covers the return fields (price, title, location, seller, photo) which is important given no output schema. However, it lacks details on pagination, ordering, error conditions, or whether authentication is needed (siblings include set_auth/auth_status). For a tool with 5 parameters and no output schema, this is moderate but not exhaustive.

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% with clear descriptions for all five parameters (query, limit, location, minPrice, maxPrice). The tool description adds no extra parameter semantics beyond the schema, so it meets the baseline but provides no added value.

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 verb and resource: 'Search Facebook Marketplace for cars' and explicitly lists the return fields (price, title, location, seller, photo). This distinguishes it from sibling tools like search_gumtree_cars and search_cars, making the purpose unambiguous.

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 Facebook-specific usage but does not explicitly compare with alternatives or state when not to use it. No mention of using search_all_cars for aggregated results or other exclusions. Usage is inferred from the tool name and first sentence, but not stated explicitly.

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