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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered. The description adds genuine context by pinning the rates to the 2026–27 financial year, but says nothing about assumptions, limitations, or that results are jurisdiction-specific estimates.

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?

One dense sentence, front-loaded with the exact capability and year, no filler or restated title.

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 read-only calculator with an already-declared safe profile, the core capability and rate vintage are clear. With no output schema, though, the shape of the result (duty amount only, or a breakdown with grant/surcharge components) is left unstated.

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 25% across 8 params, but the description partially compensates by naming the concepts that map to key booleans (first home buyer concessions → first_home, foreign purchaser surcharge → foreign_buyer, owner-occupier rates → owner_occupier). Undocumented flags such as vacant_land and house_and_land_package get no explanation anywhere.

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?

Specific verb+resource: exact transfer/stamp duty calculation for Australian states, with the concession types named (first home buyer, owner-occupier, FHOG, foreign surcharge). It is clearly distinguishable from the lending-focused siblings, though it does not name them 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?

Usage is only implied — the description tells you what it computes but not when to choose it over check_5_percent_deposit_scheme or assess_home_loan_readiness. No prerequisites (e.g. must be a purchase, must supply price/state) or exclusions are stated.

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