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

No annotations are provided, so the description must disclose behavior. It states 'Estimate' and mentions return fields, but does not clarify that the tool is read-only, safe, or any side effects. Given no annotations, this is a significant 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 sentences with no waste. First sentence gives core purpose; second provides return format and a pointer to related tools. For the tool's simplicity, this is appropriately concise.

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?

Given the tool's simplicity (3 parameters, no nested objects) and the presence of an output schema, the description covers inputs, return structure, and a reference to related functionality. Minor gap: no explanation of 'formula' or 'note' fields.

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 covers parameters 100%, but description adds value by summarizing inputs (weight, distance, service) and explicitly listing the return object fields ({cost_eur, formula, note}). This provides context 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?

Description clearly states the tool estimates shipping cost from weight, distance, and service. It distinguishes from the multitude of sibling calculate tools by specifying 'shipping cost' and referencing the related bundle.

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?

The description implies use for delivery cost estimation and points to list_bundles for related calculators, but provides no explicit guidance on when not to use it or how it differs from other calculate tools.

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