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 low, and the description clears it by disclosing non-obvious behavior: totals span all pages despite pagination, by_affiliate is capped at 100 groups, that cap is not a cross-currency ranking, and truncation is signalled by by_affiliate_truncated. It still omits rate limits, permissions, and pagination semantics.

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?

Purpose and ordering are front-loaded, and the five following sentences are dense and non-redundant, each resolving a real ambiguity (totals scope, affiliate cap, truncation flag). It is return-semantics heavy relative to guidance, but no sentence is filler.

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?

An output schema exists, so explaining return values is not strictly required, yet the description's semantic notes (cross-page totals, truncation) are genuinely additive. Gaps remain around the vague 'recent' window, pagination interaction with limit=50, and no sibling differentiation, so an agent can invoke it but not confidently choose it.

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 only 20% (just id is described), so the description must compensate. It partially does: it identifies id/affiliate_id/state as the filter set and defines what 'due' means, but page, limit (max 50), and the other enum states (pending, processing, paid, voided) get no clarification in either place.

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?

Opens with a specific verb and resource ('List recent commissions for the current account, newest first, with each affiliate's name'), so the agent knows exactly what comes back and in what order. It never distinguishes itself from the many list_* siblings (list_payouts, list_referrals, list_affiliates), which is the only thing keeping it from a 5.

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 says nothing about when to choose this tool over list_payouts, list_referrals, or get_dashboard_summary; there is no when-to-use, when-not-to-use, or alternative named. The only implied context is 'for the current account', which is not a selection criterion among the siblings.

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