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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds genuinely useful context beyond that: the data is 'Sensitive personal data', which signals handling caution, and it exposes the underlying endpoint. It does not, however, describe auth requirements, what happens with invalid ids, or the shape of the salary items.

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?

Three short fragments with zero padding, and the core purpose is front-loaded ahead of the sensitivity note and endpoint. Slightly telegraphic, but no sentence is wasted.

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 single-item read with a complete schema and no output schema, the description covers the essential elements: what is fetched, that it includes salary items, and that the data is sensitive. Auth/error behavior is unaddressed but minor for a read-only lookup.

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 id parameter is fully documented in the schema, including its source and constraints. The description's 'by id' adds no syntax or format detail beyond that, so the baseline of 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 verb+resource ('one payroll statement by id') and clarifies it returns the statement with its salary items. Implicitly distinguishes itself from the list sibling via 'by id', though it does not name cashctrl_list_salary_statements as the plural counterpart.

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 only implied through 'by id'; there is no explicit when-to-use guidance or stated alternative for bulk/listing needs. The schema's note that the id comes from cashctrl_list_salary_statements hints at the workflow, but the description itself adds no routing guidance.

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