Cian Real-Estate Search

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the safety profile is covered. The description adds real value beyond them: it enumerates concrete error classes (BadRequestError for region/room/min-max/deal-offer_type combos, TransportDownError with an inline fix, ParserDriftError) and documents data conventions (price_rub is None when Cian shows no price, never 0). It stops short of auth or rate-limit behavior.

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 '## Return Format' and '## Error Format' headings front-load the important operational facts, and the opening sentence is efficient. The Return Format block partially restates the output schema and swaps between English prose and Russian glosses, which adds some length without adding routing value.

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?

The definition covers purpose, the deal-market constraint, validation failures, transport/parser failures, and item-level fields, and an output schema exists to carry return detail. An agent has everything needed to select filters and interpret results without opening another 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%, so the schema already explains each parameter (enums, defaults, units, ranges). The description adds meaning on top by defining the price_unit semantics and the market separation rule that governs how deal and price_min/price_max must be interpreted together, which the schema alone does not tie together.

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 ('Search Cian offers by filters') and immediately clarifies the negative constraint ('there is no free-text search'), which distinguishes it from free-text siblings like yandex_search. The deal/offer_type framing makes the scope of the search 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?

Gives clear when-to-use context by explaining that 'rent' and 'daily' are separate markets that never mix in one page and whose prices are not comparable, plus the rule that commercial is rejected with deal='daily'. It does not, however, name or point to alternatives such as cian_card for fetching a single offer, so it stops short of explicit alternative routing.

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