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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description's only extra claim, 'the rate depends on the destination,' is essentially tautological and adds no behavioral context such as whether rates are current, cached, tax-inclusive, or account-specific.

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 short sentences with the core purpose front-loaded, but the second sentence restates what the first already implies, so it spends words without adding information.

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 tool with three optional parameters, no output schema, and no annotations describing return behavior, the description is under-specified: it doesn't say what a result looks like, how the optional filters combine, or how it differs from quote_call.

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 description coverage is 0% and the description says nothing about country, destination, or number_type. It hints that a 'destination country or number' is involved, but never explains the precedence between country and destination, what number_type values mean, or what happens when all three optional parameters are omitted.

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 and resource: returns the per-minute rate for a destination, scoped to this account. However, it never distinguishes itself from close siblings like quote_call, get_data_rate, or get_did_rate, so the agent must guess which rate tool applies.

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 guidance on when to use this versus quote_call (a quote for an actual call) or the other rate tools, and no mention of prerequisites or when the result would be stale. Usage is left entirely to inference from the name.

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