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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds meaningful context beyond that: the 2026 tax-year basis, the exact deduction programs modelled, and the Quebec/Ontario-specific extras. It does not disclose the shape of the result (breakdown vs. single number) or accuracy caveats, so it falls short of a 5.

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?

A single front-loaded sentence that enumerates the computed components with no filler. The list is dense but every item is informative about scope; it could be tightened slightly (e.g. grouping the Quebec/Ontario extras) without losing 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 carries the burden of describing what comes back, and it only implies a take-home figure without saying whether a full deduction breakdown is returned. It does establish the tax year and supported provinces, but an agent cannot fully predict the response shape from the definition alone.

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 description coverage is 100%, so all four parameters are already documented, giving a baseline of 3. The description does add interpretive value by explaining that provincial choice drives QPIP for Quebec and surtax/Health Premium for Ontario, and that CPP vs QPP applies. It says nothing about employmentType or rrspContribution, so it does not exceed baseline.

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 and scope: 2026 Canadian federal + provincial income tax, CPP/QPP, EI, QPIP, Ontario surtax/Health Premium, and take-home pay, for any province. An agent can tell this computes payroll deductions and net pay rather than anything mortgage- or property-related like its siblings. It stops short of explicitly contrasting with a sibling tool, so it lands at 4 rather than 5.

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: an agent infers it should call this when it needs after-tax income for a Canadian province. There is no explicit when-to-use statement, no exclusions, and none of the sibling calculators (e.g. capital_gains_tax, mortgage_affordability) are named as alternatives or complements.

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