Avito Item Card

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

The description goes beyond the annotations (readOnlyHint, idempotentHint) by detailing the exact error format and conditions (BadRequestError, NotFoundError, TransportDownError, ParserDriftError). It also clarifies an important behavioral nuance: price_rub is None when the ad has no price, never 0. This adds valuable context for handling tool results correctly.

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 compact and well-structured, with a one-sentence summary followed by clearly labeled 'Return Format' and 'Error Format' sections. Every detail earns its place, giving the agent precise information without unnecessary verbosity.

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 single-parameter fetch tool, the description covers all essential aspects: what it does, the exact structure of the response, and all expected error types. The annotations and output schema fill in the remaining details, making this description complete for the tool's complexity.

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 already fully documents the single parameter item_id_or_url with a clear description ('Item id, slug path or full avito.ru URL'), so the schema carries the heavy lifting. The tool description's 'by id or URL' adds no extra meaning beyond the schema; the return-format details are about output, not parameters. Thus, a baseline score of 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?

The description clearly states the tool's action ('Fetch one Avito listing') and its input scope ('by id or URL'). This distinguishes it from sibling tools like avito_search (which searches multiple listings) and avito_seller (which fetches seller data), making the purpose explicit and 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?

The description gives clear context that this tool is for retrieving a single, specific listing when an id or URL is available. It doesn't explicitly name alternatives or state when not to use it, but the intent is unambiguous enough to guide an agent without additional exclusions.

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