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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuine behavioral context beyond them by explaining the ranking basis (network 'good' ratings) and what the response conveys (which device works on every network), which matters given there is no output schema.

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, front-loaded with the action, with no filler. The first sentence is long and compound but each clause carries distinct information (the ranking criterion and the per-country verdict); the second sentence cleanly states the payoff.

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, read-only tool with annotations and no output schema, the description covers purpose, use case, and the conceptual shape of the result. It could say more about result ordering/limits across up to 20 countries, but nothing essential to calling it correctly 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% and the countries parameter is fully documented in the schema (ISO codes or names, max 20). The description only refers to 'the given countries' and adds no format, cardinality, or matching semantics beyond what the schema already supplies, so 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 verb (rank) and resource (modules and devices in Band Atlas) with precise scope: ranking by how many networks of the given countries rate them good, plus per-country 'works on every network' verdicts. This aggregation-over-countries behavior sets it apart from single-entity siblings like check_device and check_bands.

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?

Gives a clear use context — picking the fewest SKUs for a multi-country deployment — which tells the agent when this tool is the right choice. It does not, however, name alternatives (e.g., check_device) or state when-not to use it, so it stops short of explicit routing.

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