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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds no extra behavioral context such as the fixed buyer scenario assumptions or how results are derived, leaving that to the schema. Adequate but not additive.

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, no wasted words, with the positive trigger front-loaded and the exclusion following immediately. Ideal sizing for a narrow calculation tool.

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 and the input schema fully documents the fixed scenario assumptions, so an agent has what it needs to call it correctly. The description alone would not reveal those assumptions, which keeps it from a 5.

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 parameter descriptions already explain the price format, the fixed scenario (age 30, 40-year loan, 10% deposit, IMT Jovem, market rate) and the territory enum. The description contributes nothing beyond this, so the 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 concrete computation (net monthly income and savings needed) tied to a specific resource and jurisdiction (a home in Portugal at a given price, under Banco de Portugal rules). This is clearly distinguishable from the sibling `imt_calculate`.

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?

Gives an explicit trigger ('when asked what net monthly income and savings it takes') and an explicit exclusion naming the alternative tool to use for purchase taxes alone ('Do not use it for... `imt_calculate`'). Routing is unambiguous.

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