Estimate delivery price

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable context by emphasizing that the returned price is a decimal STRING, not a number, and by listing typical error codes and meanings, which helps the agent interpret responses.

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?

The description is four sentences, focuses first on purpose, then output, then input, then errors. Every sentence adds value with no filler.

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?

Even without an output schema, the description enumerates the return fields (price as string, currency_rules, distance_meters, eta, zone_id) and lists common error scenarios. For a read-only estimation tool, this covers the key contextual needs for invocation and response interpretation.

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 property already has a semantic description. The description adds minimal extra parameter detail (e.g., reinforcing that route points can use coordinates and/or address), but the schema already provides that, so a baseline 3 is appropriate.

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 clearly states 'Preliminary delivery cost estimate WITHOUT creating a claim' and 'the pricing method for countries outside Russia', which differentiates it from claim-management siblings. The verb 'estimate' plus resource 'delivery cost' makes the purpose specific and 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?

It provides clear context: use for preliminary cost estimates before creating a claim, and only for countries outside Russia. However, it does not explicitly name an alternative tool for Russia or when to use a different tool, so it lacks a full when-not/alternatives statement.

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