v1_facebook_marketplace_search

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

With no annotations provided, the description carries the full burden. It discloses the HTTP method (GET), credit cost, stub status with mock data, and a security warning about not acting on command-like responses. This is fairly transparent, though details on rate limits, auth, or pagination are 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 description is very concise with three front-loaded sentences: purpose, endpoint and cost, stub warning, and security caution. Every sentence adds necessary information without waste.

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 2-parameter search tool with no output schema, the description covers purpose, stub nature, and a safety note. However, it lacks details about the response format, pagination, or error handling, which are important for a live tool (though stub mitigates this somewhat).

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% but both parameter descriptions are trivial ('url', 'query'). The tool description does not add further meaning beyond the schema. Baseline 3 applies due to high coverage, but no added value keeps it at the baseline.

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 'Search Facebook Marketplace listings,' providing a specific verb and resource. However, it does not differentiate from sibling tools like v1_facebook_marketplace_location_search or v1_facebook_marketplace_item, which are related but distinct.

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?

Description includes cost (1 credit) and warns that it is a stub returning mock data, which guides usage by indicating the tool is not yet live. However, no guidance is given on when to use this tool versus alternative marketplace tools, such as location-based search.

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