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

Annotations only declare readOnlyHint=false; the description correctly signals a purchase (consistent with a mutation) and adds the important clarifications that the listed price is per unit and that own listings/bids are excluded. It says nothing about fund deduction, insufficient-money behavior, confirmation steps, or what happens to the lot on failure, which matters for a mutation tool with thin annotation coverage.

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 short sentences with no filler; the core action and the exclusivity rule are both front-loaded. The parenthetical about per-unit pricing is dense but earns its place.

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 no output schema and only a readOnlyHint=false annotation, the definition should say more about the result of a purchase — money deducted, what is returned, failure modes. It covers the essential 'what' and the 'who can't' but not the transactional consequences, so it is adequate but visibly incomplete for a buying 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 0%, so the description must carry both parameters — it only clarifies count ('для стопки', i.e. stack quantity) and the per-unit pricing model. item_id gets no explanation beyond its name, and the interaction between count and price (total cost) is left implicit, leaving a genuine gap for a 2-parameter purchase tool.

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 ('Купить лот' — buy a lot) and scopes it to the open auction page, which distinguishes it from game_auction_sell, game_auction_take and unrelated buy tools like game_shop_buy. It stops short of naming those siblings explicitly, so differentiation relies on the agent's own comparison.

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?

Provides one real exclusion — own lots and own bids cannot be bought — which is a useful when-not rule. It gives no positive preconditions (must the auction page be open? must funds be available?) and never routes the agent to game_auction_sell or game_shop_buy as alternatives, so guidance is implied rather than spelled out.

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