roamzy_country_detail

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds meaningful context beyond that: it is a reference lookup with no purchase-gate side effects, and it notes the eSIM works in all 193 countries. It doesn't discuss return format or errors, but the output schema covers that.

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 core purpose, but it uses four sentences and repeats 'reference info' in the first and last sentences. The guidance is clear and not overly long, though slightly redundant.

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-parameter reference lookup with a rich annotation set and an output schema, the description is complete: it states what the tool returns, when it should be invoked, and why it is not part of the purchase flow. No critical context is missing.

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%, with country_slug already described as 'Country slug, e.g. "esim-spain". Reference lookup only.' The description adds no new parameter semantics beyond what the schema provides, so 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 opens with 'Reference info: the per-MB rate for a specific country,' a specific verb/resource combination. It clearly distinguishes this from purchase flow tools by saying 'rates are reference info, not a purchase gate' and from list-style siblings by focusing on one country.

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?

Explicitly states 'Call ONLY if the user explicitly asks about price for their destination' and 'DO NOT call this during purchase — the user does not need to pick a country to buy.' This provides both when-to-use and when-not-to-use, even naming a concrete example.

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