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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, and 'Read only.' merely repeats them, earning no credit. The phrase 'per payment method' does add useful shape information about how results are grouped, but nothing is said about behavior when provider is unspecified or how many methods are returned.

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, front-loaded with the resource and its contents — efficient overall. The trailing 'Read only.' spends a sentence on something the annotations already convey.

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 simple read with one optional parameter, the annotations cover the safety profile and the description covers the returned fields adequately despite there being no output schema. What is missing is only the relationship to fee-preview tooling and default-provider behavior, a minor gap.

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% on the single optional provider parameter, so the baseline is 3. The description's 'per payment method' helps map that parameter to gateway concepts, but it adds no detail about the active-gateway default beyond what the schema already states.

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 names a concrete resource and enumerates its contents (platform fees, processing fees, payer attribution) per payment method, so an agent knows exactly what data comes back. It falls short of a 5 because there is no verb framing and it never distinguishes itself from the closely related sibling preview_payment_fees.

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 call this versus preview_payment_fees or the other financial getters (get_financial_metrics, get_balance). The only directive sentence, 'Read only.', is a safety restatement rather than usage guidance, and nothing says when to pass provider or what happens when it is omitted.

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