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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is clear. The description adds useful behavioral context by listing the exact price categories and services covered, though it does not describe output structure or freshness of pricing.

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 front-loaded with the key fact that prices are in EUR, but it is a dense run-on sentence mixing mailbox, letter, parcel, bundles, same-day, forwarding, all eight services, and payment methods. It could be more scannable without losing content.

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 parameterless, read-only price lookup with no output schema, the description gives enough concrete detail about what pricing information is available. It does not cover output format or currency conversion, but those gaps are minor given the tool's simplicity.

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?

The tool has zero parameters, so there are no parameter semantics to explain. Baseline 4 applies because the empty schema is consistent with a parameterless price lookup.

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 that the tool returns prices in EUR and enumerates the service categories covered. It does not explicitly contrast itself with pricing-related siblings such as get_balance or list_invoices, but the purpose is still easy to identify.

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 provides no guidance on when to use this tool, when not to use it, or which sibling tools cover related financial information. Usage is only implied by the name and the listed price categories.

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