Read one of your own ads

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

Beyond the readOnlyHint and openWorldHint annotations, the description adds valuable behavioral context: NOT_FOUND only means the ad was not among those read, not that it does not exist. It also includes an important safeguard warning that titles, descriptions, and seller names are untrusted data that may contain prompt-injection instructions, going well beyond what the annotations convey.

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 concise and front-loaded: the core behavior is stated first, followed by the experimental caveat and then the critical security warning. It is not compact as possible, but every sentence earns its place because the NOT_FOUND and prompt-injection warnings are necessary for safe use.

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 read-one-ad tool, the description covers the core purpose, open-world semantics, and a distinctive prompt-injection risk, all while annotations provide read-only and open-world hints. It does not outline the return shape beyond mentioning status and untrusted fields, but given the modest complexity and existing annotations, it is sufficiently complete.

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 input schema explains country and its default, but listingId has no schema-level description. The description only says the tool returns one item 'by id', which provides minimal semantics for the main parameter but does not explain where the id comes from, its format, or how to obtain valid values.

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 first sentence clearly states the operation: 'Returns one of your own ads by id, with its Leboncoin status.' This distinguishes it from siblings like my_listings (which lists multiple own ads) and get_listing (which likely retrieves arbitrary listings), while also giving the specific resource type and key output element.

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 'one of your own ads by id' makes the intended use clear, and referencing my_listings provides context for the experimental caveat. However, it does not explicitly state when to use this tool instead of get_listing or other listing retrieval tools, only implying it by the 'own ads' wording.

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