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

With no annotations, the description carries the full burden, and it does well: it states that both annual and monthly returns are calculated, provides band-based interpretation, and adds the important caveat that this is an initial indicator, not an absolute rule. Only the exact output formatting is left unspecified.

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?

The description is compact and front-loaded: the core computation is stated first, followed by interpretation thresholds and a caveat. Every sentence contributes information; there is no repetition of schema data.

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 simple two-parameter calculator with no output schema and no annotations, the description covers the inputs, the calculation type (annual and monthly yield), interpretation bands, and a caveat. It does not explicitly describe the return format, but the tool's simplicity makes this a minor omission.

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 the description adds the conceptual link that the parameters are used to compute rental yield and the interpretation thresholds. It does not add new format or constraint details beyond the schema, so the baseline 3 is appropriate.

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?

The description opens with a specific verb ('Calcula') and a precise object ('rental yield') tied to two named inputs: property value and monthly rent. Rental yield is a distinct concept among the siblings such as max_price_from_rent or calculate_cet, so the tool is easy to tell apart.

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?

The description makes the usage context clear by naming the required inputs and providing interpretation thresholds for the resulting indicator. It does not explicitly mention alternatives or when not to use it, but the calculation scenario is unambiguous.

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