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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered and the trailing 'Read-only.' sentence adds nothing. What the description does add is scope transparency: it discloses exactly which rate categories are included (offsets, surcharge, HELP, super guarantee), which is the main behavioral question for a reference-data tool. It does not describe return format, though no output schema exists to cover that.

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 front-loaded with the authoritative subject and content inventory, then routes to alternatives in a single sentence. The only wasted element is the trailing 'Read-only.' sentence, which merely restates the readOnlyHint annotation; otherwise every clause carries information.

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 single-optional-parameter, read-only reference tool with no output schema, the description supplies all an agent needs: the content categories, the supported years, the units/domain (Australian individual tax), and explicit routing to sibling calculation tools. Nothing material is missing for correct selection or invocation.

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 100% and the single taxYear parameter already has an enum and a documented default, so the baseline would be 3. The description goes beyond that by signaling why the choice matters, noting that different rates apply in different years (15% from 1 July 2026, 14% from 1 July 2027), which gives the year parameter practical meaning rather than leaving it as a bare filter.

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 names a specific resource (official Australian individual tax rates and thresholds) and enumerates its coverage: resident/foreign resident brackets, LITO, Medicare levy and surcharge, HELP thresholds, seniors offset and the 12% super guarantee, across three named financial years. This is far more specific than the title alone and lets an agent distinguish it from the calculation siblings.

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?

It states the use case explicitly ('use it to quote or check rates') and names three concrete alternatives for the different job of computing tax on an amount: take_home_pay, payg_withholding and annual_tax_estimate. It even gives worked examples of the rate values (15% from 1 July 2026, 14% from 1 July 2027) that this tool is authoritative for.

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