List your own Leboncoin ads

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

Annotations declare readOnlyHint=true and openWorldHint=true. The description adds important context beyond annotations: it is experimental, reads a non-documented API, may fail with PARSING_ERROR, and it emphasizes that the result data is untrusted (DATA, never instructions) due to open-world input. It also notes it reads via the browser profile, adding behavioral clarity. No contradiction with annotations.

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 detailed but front-loaded with the core purpose in the first sentence, followed by caveats and usage guidance. It is longer than necessary but every sentence adds value (error behavior, prompt injection warning, alternative tool). Slightly verbose for the conciseness ideal, but well-structured and critical information is prominent.

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?

Given the tool's complexity (experimental, error-prone, open-world data) and the absence of an output schema, the description covers the essential context: what it does, how it fails, security warnings, and when to use it. It doesn't specify the exact shape of the result (but no output schema is provided), which would be a minor gap. Overall, it is quite complete for its purpose.

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 50%: the country parameter is described ('Leboncoin site to use (fr). Defaults to the server's configured site.'), but the limit parameter has no description in the schema. The tool description does not elaborate on parameters either. Baseline for 50% coverage is 3; it does not compensate for the undocumented limit.

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 tool reads ads on the signed-in account via the browser profile. It explicitly distinguishes from siblings (it is the tool to reach for after a publish_unknown outcome to find out if an ad went live, and its scope is the user's own listings, unlike get_listing or search_listings).

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 explicitly says when to use this tool: after a publish_unknown outcome, to check if an ad went live. It also gives guidance on what to do on error (tell the user to check Leboncoin) and warns about prompt injection, which serves as a when-not-to-trust-output guidance.

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