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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so the safety profile is covered. The description adds meaningful behavioral context beyond that: the default assumption that assets are treated as below the limit unless specified, plus the income components considered. It does not describe output shape, though an output schema exists.

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?

Front-loads the calculation purpose, then usage, then exclusions, then the default assumption. Four dense sentences with no filler; every clause carries routing or computation information.

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 deterministic calculator with a full output schema and safety/idempotency annotations, the description supplies everything an agent needs: when to invoke, what inputs mean, default assumptions, and which siblings to prefer instead. Return values need not be explained given the output schema.

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%, so the baseline is 3. The description goes further by clarifying that toetsingsinkomen is gross annual income including holiday allowance and that the partner's income is combined, and it restates the vermogen default — semantics that enrich the parameter meaning rather than merely repeating it.

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 (berekent) and resource (zorgtoeslag), plus the output granularity (per maand en jaar) and the driving input (toetsingsinkomen). It explicitly names the sibling tools it is not (nmi_huurtoeslag, nmi_kindgebonden_budget), so an agent can route 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?

Provides explicit when-to-use ('Gebruik bij vragen over recht op of hoogte van zorgtoeslag') and when-not-to-use with named alternatives for both rent and children. Nothing is left to inference.

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