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

The annotations already establish readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so safety is covered. The description adds one genuinely non-obvious rule — a wholesale price applies to the whole order once regular-price goods reach 30 000 ₽ — but says nothing about what the returned total includes (goods only vs. delivery/VAT), which is the key behavioural ambiguity for a quoting tool.

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, front-loaded with the core action and followed by the pricing rule; nothing is padded. The second sentence is slightly awkward in its phrasing ('по обычным ценам на весь заказ') but still 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?

The tool is a simple read-only computation with a fully documented single parameter and rich annotations, and no output schema exists, so the description need not describe the return shape. However, for a pricing tool it omits whether the total covers delivery or tax and whether the quote is authoritative for checkout, leaving a real gap.

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% and the nested items object documents art, qty, and the optional name field, so the schema carries the parameter burden. The description adds nothing about quantities, units, or the variant-disambiguation role of name, so 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?

The description gives a specific verb and resource — 'Считает сумму заказа по ценам сайта' — so an agent knows this computes an order total rather than placing an order or quoting delivery. It does not name a sibling such as delivery_quote or create_order to sharpen the boundary, so it stops short of a 5.

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?

There is no explicit when-to-use or when-not-to-use guidance, and no mention of sequencing relative to create_order or delivery_quote. The agent must infer that this is a pre-checkout pricing step from the verb alone.

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