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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description does surface one useful behavioral assumption, the implicit 35% debt ceiling encoded in the returned field max_monthly_debt_35pct, but it adds nothing about currency handling, rounding, or assumptions behind the ratio.

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 compact sentences with the core purpose front-loaded. The return-field enumeration duplicates the existing output schema, so it is mild filler rather than earned content, but the total length is still tight.

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 two-parameter, read-only, deterministic calculator with a published output schema and a sibling list, the description covers purpose, output shape, and a cross-reference to the calculator bundle. The remaining gap, disambiguation from calculate_debt_to_income/calculate_debt_capacity, is marginal for such a simple computation.

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% for both parameters (net monthly income EUR, existing monthly debt payments EUR), so the schema carries this dimension. The description only alludes to income and debt through the term 'debt-to-income' and adds no format or unit information beyond the schema.

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 and output resource: it computes a debt-to-income ratio plus maximum additional loan capacity, which is more concrete than the name alone. However, it does not distinguish itself from the near-identical siblings calculate_debt_to_income and calculate_debt_capacity, leaving the agent to guess which one is intended.

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?

There is no when-to-use guidance, no prerequisites, and no mention of the obvious alternative tools (calculate_debt_to_income, calculate_debt_capacity, calculate_debt_capacity/loan_to_value). The only pointer is 'See list_bundles', which is navigational, not a usage rule.

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