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

Annotations already cover the read-only/idempotent profile, but the description adds substantive behavior: no auth or payment header required, no charge incurred, and the exact fee computation formula including rounding and min-fee interaction. It also explains that the fee_rate reflects any live promotion, which the agent cannot infer elsewhere.

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?

Front-loaded with the core purpose, then progressively adds formula and quote-retrieval detail. Every sentence carries information, though the third paragraph is fairly dense and could be tightened slightly.

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?

Even though an output schema exists (so return fields needn't be spelled out), the description goes further by explaining the fee formula and the authoritative per-route quote path. An agent has everything needed to call this correctly and interpret its output.

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 tool takes zero parameters, so the baseline is 4 and there is nothing for the description to clarify. It correctly implies a parameterless global read.

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 ('Get the fee schedule') and immediately enumerates the returned fields: route, amount range, fee rate, minimum fee. This is clearly distinguishable from billing-related siblings like get_account_balance or get_payment_status, which report state rather than 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?

Gives explicit context for use ('so you can budget before you have an account') and routes the agent to the 402-challenge path when an exact per-request total is needed. It does not explicitly name or exclude any sibling tools, so it falls short of a full 5.

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