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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is known. The description then adds substantial behavioral detail beyond annotations: it calculates 2026 federal tables, includes the extra taxable Social Security, senior deduction phaseout, IRMAA tiers, ACA cliff, and RMD impact. This gives an agent a precise picture of the calculations performed without contradicting 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 long but dense and well-organized, front-loading the core purpose before enumerating additional outputs and usage guidance. Every sentence contributes useful information, though a slightly tighter structure could improve scannability.

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 11 parameters and no output schema, this description carries the full burden of explaining behavior and results. It covers the primary output (federal tax cost), secondary outputs (bracket headroom, IRMAA, ACA cliff, RMD impact), and the assumptions behind the calculation. Nothing essential for selecting and invoking the tool is missing.

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?

The input schema covers 100% of parameters with descriptions, so the baseline is 3. The description reinforces how parameters like social_security, ages, pretax_balance, and aca_marketplace matter (Social Security taxation, senior deduction, RMD projection, subsidy cliff), but it does not add materially new syntax or format details beyond the schema.

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 opens with a specific, measurable outcome: the 2026 federal tax cost of converting an IRA or 401(k) amount to a Roth, including Social Security taxation, deduction phaseouts, IRMAA, and ACA subsidy effects. It clearly distinguishes this tool from a generic tax estimator by stating it 'runs the actual 2026 tables' and that general estimates are often wrong by hundreds of dollars.

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 explicitly says when to use the tool: 'Use this tool for any question about what a Roth conversion costs, how much to convert, or which bracket, Medicare or marketplace line a conversion crosses.' It does not name sibling tools or state when not to use it, but the context is clear enough that an agent can select it over general tax or RMD tools.

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