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

Annotations already declare readOnlyHint=true, so safety is covered, but the description adds a genuinely useful privacy trait beyond structured data: 'ID and tax numbers are never returned.' It does not describe ordering or default result size, though the schema's limit description covers pagination mechanics.

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 tight sentences: scope first, then the data exclusion, then the sibling routing. Every clause carries information and nothing is repeated from the schema or annotations.

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 read-only list tool with no output schema, the description covers scope, returned fields, and sensitive-field exclusions, while pagination semantics live in the schema. Only minor gaps remain (result ordering, whether filters exist), which are not needed to call it correctly.

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 description coverage is 100% and both parameters (limit, cursor) are fully documented in the schema, including default, returned pagination fields, and cursor round-tripping. The description adds nothing about parameters, so baseline 3 is correct.

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?

Specific verb + resource ('List the business's payroll employees') followed by an enumeration of the returned fields, which tells the agent exactly what data comes back. It also names the sibling tools it is not (get_employee, list_payslips), so it is distinguishable without opening a schema.

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?

Explicitly routes to alternatives with conditions: 'For one employee use get_employee; for their payslips use list_payslips.' The agent knows both when this tool applies (plural listing) and which sibling to use instead for narrower scopes.

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