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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds real behavioral context beyond them: it discloses the payload contents and, notably, that contact data is deliberately withheld — a limitation the agent could not infer from structured fields. It does not mention rate limits or whether url/slug must match an existing entry, 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?

Two sentences: purpose first, then the routing caveat. The field enumeration is long but each item is a distinct content guarantee, so it broadly earns its place; still, the list could have been trimmed to the most decision-relevant fields.

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?

There is no output schema, so the description carries the return-value burden itself and does so by enumerating the card contents and explicitly stating what is absent (contacts). Combined with a fully documented two-parameter schema, an agent has enough to call it correctly; only minor gaps remain around input precedence.

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%: the schema already explains that url is a ploshadkin.ru card link and slug comes from search_venues. The description adds no parameter-level detail (e.g. whether slug or url takes precedence), 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?

States a specific verb+resource ('Подробная карточка площадки') and enumerates exactly what the card contains: halls, seating capacity, indicative price, cuisine, parking, accommodation, photos. It explicitly contrasts itself with the sibling request_quote, so an agent can distinguish it from the other venue-related tools without opening any schema.

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 an explicit exclusion plus the alternative to use instead: contacts are not returned, so for a free date and estimate use request_quote. That is a when-not/alternative pair, which is the strongest form of routing guidance.

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