Get full listing details

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

With no annotations, the description carries the burden of disclosing behavior. It adds a useful behavioral detail: 'Falls back to server-side rendering when the API fails,' which is beyond the schema. However, it does not explicitly state that this is a read-only operation (though 'get' implies it) or mention any side effects, rate limits, or authentication requirements. The fallback is a positive addition, but coverage remains moderate.

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 two sentences, front-loaded with the core purpose and then quickly covering input variations and fallback behavior. Every sentence adds value with no repetition or fluff. It is appropriately sized for the tool's simplicity.

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 low complexity (single parameter, no output schema), the description is nearly complete. It lists the returned data fields, specifies accepted input formats, and mentions a fallback mechanism. It doesn't cover error cases or example responses, but for a straightforward fetch operation, this is sufficient. Slight deduction for not explicitly stating what happens on not-found or invalid input.

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 description coverage is 100%, so the parameter `itemId` is fully described in the schema as 'Listing id (numeric string), web slug, or full item URL.' The description simply repeats this information ('Accepts the numeric listing id, a web slug, or a full item URL') without adding new semantics. Baseline for high coverage is 3, and no extra value is provided beyond the schema.

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's purpose: 'Get detailed information about a single Wallapop listing' and enumerates the specific fields (description, condition, price, images, etc.). This distinguishes it from siblings like get_seller, which focuses on seller data, and search_products, which is for searching. The verb 'get' and resource 'listing' are 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 when to use this tool (when you need details of a single listing) and even provides flexible input formats (numeric id, slug, or URL). It does not explicitly exclude alternatives or mention when NOT to use it, but the context from sibling names and the clear purpose give sufficient guidance. The fallback note also hints at reliability handling.

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