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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and locality are covered. The description adds a useful behavioral detail — that omitting the address yields general conditions rather than an error. It does not indicate what the response contains (a price value, a range, terms), which is a modest gap.

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 purpose and ending with the optional-parameter rule. Nothing is redundant and every clause carries information.

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 a single optional-parameter, read-only lookup with no output schema, the description covers geography, input shape, and the no-address fallback. What's missing is any hint of the response form (fixed price vs. conditions), which an agent calling blindly might want.

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 coverage is 100% and the schema already labels the address field. The description nevertheless adds real meaning: the address refers to a venue/house format, applies only within SPb/Leningrad region, and is optional with a defined fallback. That goes beyond the schema text.

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 resource and outcome: delivery price by address (venue, house) within St. Petersburg and Leningrad region. This is clearly a read/lookup of a delivery cost rather than an ordering action. It doesn't explicitly distinguish itself from the closest sibling (quote_gingerbread), but the scope is 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?

"Без адреса — общие условия" gives a usable rule for when to omit the parameter, which is genuine conditional guidance. However, it says nothing about when to prefer this tool over siblings like quote_gingerbread or estimate_cake, leaving cross-tool selection to inference.

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