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

Annotations already establish that this is a safe read-only calculator, so the description's main burden is explaining what it computes. It does that well by enumerating the four outputs, though it adds no detail about precision, assumptions, or formatting.

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 single dense sentence front-loads the calculator's role and then lists the outputs efficiently. It is appropriately sized, though the semicolon-heavy structure is slightly harder to scan.

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?

With no output schema, the description usefully explains what the calculator returns, covering the main outputs an agent would need. It still leaves gaps around currency semantics and sibling routing, but is otherwise complete for a read-only calculation tool.

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 only 33%: the purpose enum is documented but currency and total_budget are not. The description clarifies that total_budget is the buyer's TOTAL all-in budget, but it says nothing about currency behavior or how currency interacts with the calculation.

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 states a specific resource and the calculations it performs: max property cost after VAT/legal/registration, residency threshold, long-let income, and project counts by district. It is clear what the tool does, but unlike the calibration example it does not explicitly differentiate itself from siblings such as purchase_costs.

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?

Usage is implied by the budget-oriented framing, but the description never states when to choose this over purchase_costs or match_neighbourhoods. It lacks explicit when-to-use or when-not-to-use guidance.

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