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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuinely useful context beyond them: the cost model ('Flat 5 points per successful run') and a breakdown of the returned payload, which matters since there is no output schema. It does not mention auth or rate limits, keeping it short of 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?

The purpose and input scope are front-loaded in the first clause, and the cost sentence is a clean, useful addition. The middle enumeration of returned fields is long but earns its place given the absence of an output schema.

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 single-parameter read tool with no output schema, the description supplies both input guidance and an inventory of returned fields plus the cost, which is close to everything an agent needs. It stops short of describing pagination or error behavior, but those are minor here.

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 the single 'item' parameter is already documented with an example ID in the schema. The description's 'id or URL' adds only marginal restatement of that fact, so the baseline 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?

States a specific verb and resource ('Get a full Avito listing') and constrains the input scope to 'by id or URL', which implicitly separates it from the run_avito_items_search sibling. It never names that sibling explicitly, so the differentiation is inferred rather than stated.

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 'by id or URL' phrasing implies you use this when you already have an identifier rather than search terms, but there is no explicit when-to-use statement or named alternative. An agent must infer that run_avito_items_search is the counterpart for keyword discovery.

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