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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), so the description is not obligated to restate them. It adds real value by specifying the rate regime in force (15 Feb 2023, 1%–6% bands) and flagging that outputs are indicative, not legal advice.

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?

Front-loads the core purpose, scope, and the calculate_absd routing before any secondary material. The closing marketplace blurb and disclaimer are non-essential padding, but they are short and do not obscure the operational content.

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 previews the return ('tier-by-tier breakdown') and states the rate schedule, applicability, and caveat. It stops short of describing non-residential rates or rounding/currency formatting, a minor gap for a two-parameter calculator.

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%: 'price' is documented in the schema while 'propertyType' has an enum and default but no description. The description notes the residential rate schedule and thus implies propertyType matters, but it never explains non-residential treatment or the price-vs-market-value basis beyond the schema's own text, so it only marginally compensates for the gap.

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 (calculate) and resource (Buyer's Stamp Duty for Singapore property purchases), plus the output shape ('tier-by-tier breakdown'). It explicitly differentiates itself from the sibling calculate_absd, so an agent can select between them without opening either schema.

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?

Explicitly routes the agent: BSD applies to every buyer, while foreigners, PRs and owners of other homes additionally owe ABSD and should call calculate_absd 'for the total'. This names the alternative and the condition that selects it.

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