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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond them: there is a finite built-in tariff table with limited coverage, the result is an estimate, and there are two distinct computation paths. It omits error behavior when no valuation is supplied and any accuracy/caveat statement.

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?

Three tight sentences, no filler, with the core purpose and the two usage modes front-loaded before the discovery hint. Every sentence carries information the agent needs.

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 6-parameter, zero-required calculator with no output schema, the description covers the input modes but says nothing about the return value shape (monthly figure? breakdown?) or what happens when municipal_valuation is absent. Adequate to start a call, but an agent still has to guess at the result contract.

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 50%, and the description compensates for part of the gap by explaining the municipality-vs-rate_in_rand override relationship and the list_municipalities flag. However it never mentions 'category' (the only enum parameter) or 'municipal_valuation' as the core input, leaving the two most important non-documented parameters unexplained.

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 ('estimates') and resource ('municipal property rates') with the domain scoped to South African properties valued from a municipal valuation. That is enough to tell it apart from the bond_repayment / transfer_duty / purchase_costs calculators, though it never names a sibling explicitly.

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 clear operating instructions: either select a municipality from the built-in tariff list or supply the cent-in-the-rand rate and rebate yourself, plus a discovery path ('call with list_municipalities=true to see which municipalities are covered'). No explicit when-not or edge-case exclusions, so it stops short of a 5.

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