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

Annotations already declare a non-read-only, open-world, non-idempotent, non-destructive mutation, so the bar is lower; the description still adds real behavior: payment method depends on buyer_type, goods ship only after payment, and the order is legally attributed to the buyer with a linked policy. It does not warn that repeated calls are non-idempotent and may create duplicate orders, nor mention any rate limits, which is the main remaining gap for a committing write.

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?

Front-loaded with the hard precondition in the second sentence, then fulfillment and payment consequences. Four sentences, each doing work; the legal-attribution sentence is longer than needed but carries genuine compliance meaning.

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?

For an 11-parameter, 7-required committing mutation with no output schema, the description covers preconditions, payment routing and fulfillment timing well. It does not say what the call returns (order id, payment link, status), which the agent would need to report back to the buyer since no output schema exists.

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 every parameter including enum semantics for buyer_type and vat_needed is documented in the schema; the baseline of 3 applies. The description reinforces the buyer_type branch meaning and ties the explicit-confirmation prose to the confirmed_by_user/accepted_terms gates, but adds no syntax, format or edge-case detail beyond the schema.

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?

"Оформляет заказ" names a specific verb and resource, and the surrounding sentences make clear this is the final committing step rather than a cart/quote helper. It does not name the sibling it is not (e.g. create_cart_link or quote_cart), so an agent must infer the boundary from the confirmation gate rather than from an explicit contrast.

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 an unusually strong precondition: call ONLY after showing the buyer composition, total and terms and receiving explicit confirmation in dialogue. It also branches the outcome by buyer_type (person → payment link via SBP, org/IP → manager invoice). What it lacks is a named alternative for the pre-confirmation stage, leaving the routing to cart/quote tools implicit.

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