Avito Item Card

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

Annotations already cover readOnly/idempotent/openWorld, and the description adds real behavior beyond them: the JSON-LD-then-DOM extraction order, the path-normalization/redirect behavior, and the None semantics for price, location, posted_at, views and seller. It stops short of describing latency, rate limits, or failure conditions, which is why it is not a 5.

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?

Front-loaded with the core operation, then input handling, then output semantics, then a pointer to the guide resource. The URL-parsing sentence is dense and slightly over-detailed for a tool description, but every sentence carries information.

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?

With an output schema present, the description wisely does not enumerate return values, yet still flags the important null semantics (price never 0). Full field list and error codes are deferred to a guide resource, which is an appropriate boundary for a single-parameter read tool.

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% and there is only one parameter, so the baseline is already met; the description nonetheless adds concrete meaning the schema does not — which URL forms are valid, that query/fragment is stripped, and that numeric/slug input is rewritten to /{id}. That is genuine added value over the schema's terse 'Item id, slug path or full avito.ru URL'.

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 states a specific verb and resource ('Read an Avito item over CDP') and even names the extraction strategy (JSON-LD first, DOM fallback). It is clearly distinguishable from avito_search and avito_seller by being item-scoped, though it never explicitly contrasts itself with those siblings.

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?

Usage is only implied: supply an item id or URL and the card is fetched. The accepted URL shapes (item path, slug path, city/category path) give useful input context, but there is no explicit when-to-use versus avito_search, no stated prerequisites, and no note on when the DOM fallback triggers.

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