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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint. The description adds substantial behavioral context beyond those: it specifies the tax year (2026), lists all computed outputs (taxable share, bracket room, NIIT, IRMAA tier), and notes that IRMAA is for income 'two years later.' This provides a clear picture of what the tool does and what it returns, exceeding the minimum expected given the annotations.

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 a single, information-dense sentence that front-loads the primary purpose (the tax estimate) and then lists components. It is efficient and lacks redundancy, though it is somewhat long. The usage guidance is appended at the end, which is logical. Overall, it earns its place with no wasted words.

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?

Given the tool's complexity (6 parameters, no output schema), the description is remarkably complete. It names every major calculation it performs, the inputs it uses (ages, income types), and the outputs (bracket room, IRMAA tier). It also states the tax year and the 'Federal only' scope. An agent can confidently call this tool and understand what it does without needing external context.

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 every parameter is already documented. The tool description does not add meaning beyond the schema; it only names the factors but does not describe each parameter's role or interactions. Baseline 3 is appropriate because the schema carries the full burden, and the description neither adds nor contradicts parameter semantics.

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 states a specific verb-resource pair: it computes a retiree's federal income tax for tax year 2026, enumerating the exact components (Social Security taxable share, standard deduction, brackets, NIIT, IRMAA). It explicitly says 'Federal only' and names the scope, which distinguishes it from sibling tools like state_retirement_taxes or rmd_calculate.

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?

The description gives explicit usage guidance: 'Use this tool for any question about how much federal tax a retiree owes, how much of Social Security is taxable, or how much room is left in a bracket, rather than estimating from memory.' It also clarifies that it is 'Federal only,' implicitly ruling out state tax questions. This directly informs an agent when to select this tool over alternatives.

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