USSD pricing

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

Annotations already provide readOnlyHint=true and openWorldHint=true, so the description's simple 'Returns' statement is consistent. The description does not add behavioral details beyond what annotations offer (no mention of rate limits, side effects, or data freshness). With annotations present, a score of 3 is appropriate.

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 a single sentence that efficiently conveys the tool's purpose and a key requirement. No fluff or redundancy.

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?

The tool is simple (no parameters, no output schema), and the description adequately states what is returned. Given the annotations cover safety profiles, the description is sufficient for an agent to decide to invoke it. However, it could optionally mention the return format or any pagination, but not required for completeness.

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 input schema has no parameters (0 params, 100% schema coverage). The description adds no parameter explanations, but none are needed. Per guidelines, with 0 parameters baseline is 4, and the description does not need to compensate.

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 the tool returns specific USSD pricing data: 'shared short code, per-network session prices, and per-length monthly extension rentals.' The name includes 'ussd' which distinguishes it from the sibling 'hellio_get_pricing' likely for SMS pricing.

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 mentions a required scope ('Requires the `ussd` scope.'), providing clear authentication context. However, it does not explicitly state when to use this tool versus alternatives, nor when not to use it. The context implies it's for fetching pricing, which is distinct among siblings.

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