v1_facebook_marketplace_location_search

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

With no annotations, the description fully discloses that it returns mock data, costs 1 credit, and importantly warns that responses are data and should not be treated as instructions—a critical safety trait.

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?

Three sentences covering purpose, endpoint/cost, and stub warning with safety directive. No redundancy, front-loaded with the action, every sentence adds value.

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 simple stub tool with no output schema, the description covers the essential aspects: action, endpoint, cost, stub status, and safety warning. Lacks details on mock data structure but is adequate given the stub nature.

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% as both 'url' and 'query' have descriptions, though those descriptions are minimal (just their names). The tool description does not add additional meaning beyond the schema, so baseline 3 is appropriate.

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?

Clearly states the action 'Search Facebook Marketplace locations by query', which distinguishes it from the sibling 'v1_facebook_marketplace_search' (which likely searches items). Also provides the API endpoint and cost.

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?

Indicates that this is a stub endpoint returning mock data, implying it should be used for testing only. While it does not explicitly compare to alternatives, the tool name and context make the use case clear.

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