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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: rules are seeded from contract annexes and statements, and are updated by the daily statement check and the settlement import — telling the agent the data is derived and may lag or be refreshed by background processes.

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 sentences, front-loaded with the resource and scope, then provenance. The field list is telegraphic but each item is informative; nothing is obviously padded, though the compressed enumeration reads stiffly.

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 return-shape explanation is not required, and the description still sketches what each rule contains. Combined with 100% schema coverage and read-only annotations, an agent has enough to call this correctly; only the sibling routing guidance is missing.

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% and the single `account` parameter is fully documented with accepted forms (id, label, domain, 'channel country') and its optionality. The description's '(or one)' restates the optional scoping without adding format detail beyond the schema; baseline 3 applies.

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 resource (commission rules) with a scope qualifier (every account, or one) and enumerates the fields returned: category, percentage, net/gross basis, fixed fee, validity, source. An agent can distinguish this from commission_rules_set (mutation) or commissions_get by the listing verb, though no sibling is named explicitly.

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?

Usage is implied rather than stated: the field enumeration suggests 'use this to inspect which commission rate applies', and 'every account (or one)' implies the account parameter narrows scope. There is no explicit when-to-use, when-not, or pointer to commissions_get / commission_actual_sync for related questions.

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