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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior: the specific tax year (2026) and the computational rules applied (15.3% on 92.35% of profit, half-SE deduction), which no structured field conveys.

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 sentence front-loads the eligibility hook and the computed outputs, followed by a reference URL. Efficient and scannable, though the rhetorical '1099 income?' opener is slightly promotional rather than purely informational.

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 results, and it does list the four returned figures (SE tax, half-SE deduction, income tax, quarterly payment). It omits jurisdiction/currency assumptions and output precision, but is otherwise sufficient for a zero-required-parameter calculator.

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 six parameters (profit, wages, other, withheld, filing, qbi) are already documented in the schema. The description touches profit and the QBI-adjacent deduction concept but adds no input syntax or constraint detail beyond what the schema provides — baseline 3 applies.

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 the specific resource (self-employment tax on 1099 income) and enumerates the exact outputs computed: 15.3% SE tax on 92.35% of profit, the half-SE deduction, 2026 federal income tax, and per-quarter estimated payments. The '1099 income?' framing implicitly separates it from the generic income_tax_calculator and salary_calculator 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?

The opening '1099 income?' implies the audience and condition for use, but the description never states when to use a different tool (e.g. income_tax_calculator for W-2-only filers) or any prerequisites. Usage is inferred rather than instructed.

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