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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds provenance context ('from official pages', 'source URLs') and dataset scope (900+ services), which is useful, but says nothing about behavior for unknown services or how results are shaped.

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?

A single dense sentence, front-loaded with the resource and scope, with the enumerated data fields following. No wasted words, though the field list is packed enough to be slightly clause-heavy.

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 read-only lookup with no output schema, the description effectively enumerates the return contents (methods, availability, gift cards, crypto, billing checks, URLs), which compensates for the missing output schema. Combined with full schema coverage, an agent has enough to call it correctly.

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 documents both the lang enum/default and the service parameter including the 'omit for dataset links' case. The description adds no parameter syntax or format detail beyond the schema, so the baseline 3 applies.

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 (payment facts for 900+ foreign services) and enumerates the exact data categories returned (payment methods, Russia availability, gift cards, crypto, billing-country, source URLs). An agent knows precisely what the tool yields, though it does not explicitly distinguish itself from siblings like get_foreign_card_terms.

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?

There is no when-to-use guidance, no mention of the sibling tools, and no statement of when a different tool (e.g. get_foreign_card_terms or how_to_pay_from_russia) is the better choice. The agent must infer the use case entirely from the name and description.

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