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

Annotations already establish read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely new behavioral context the annotations do not: the returned field set (title, price, location, coordinates, image, seller) and the billing rule '1 point per returned record', which directly affects how an agent sizes max_items.

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?

Three tight sentences: capability, return shape, cost. Front-loaded with the search action and free of filler. The middle clause is a long filter list, but every listed dimension maps to an actual parameter, so nothing is padding.

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 11 parameters, no output schema, and no nested objects, the description does the work of summarizing the return fields and the per-record cost, and the schema documents pagination (start_page, max_items) and value ranges. The main gap is the missing sibling routing to run_avito_items, which is minor for an otherwise self-contained search 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 description coverage is 100%, including enum options for sort and seller_type and example values for region/category, so the schema carries essentially all parameter meaning. The description only restates the filter categories in prose, adding no syntax or format detail beyond what the schema already provides, so the baseline 3 applies.

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?

Clear verb+resource ('Search Avito listings by keyword') plus an enumeration of supported filter dimensions, so an agent immediately knows this is the keyword-search entry point. It does not, however, distinguish itself from the sibling run_avito_items (item lookup by ID), leaving the boundary between the two to inference.

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: the presence of a required 'keyword' plus filters signals 'use this when you want to search rather than look up a known item', but the description never states when to prefer run_avito_items, run_avito_categories, or a competing marketplace search tool. No prerequisites, no exclusions.

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