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

Annotations already cover the safety profile (read-only, idempotent, closed-world, non-destructive), so the description's added value is the provenance and currency note ('Taken from IRS FAQs and forms fetched Oct 2026') plus the disclosure that behavior changes across years (2026 code TT restriction). That is genuinely useful context an agent cannot get from the annotations, though return format is unstated.

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 dense sentence front-loads the core purpose and then packs the specific coverage list, ending with the source note. It is slightly run-on with a long parenthetical, but every clause carries substantive information and nothing is redundant.

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 must convey what comes back, and it does so concretely: eligibility rules, year coverage, excluded filing status, SSN rule, FLSA eligibility, and the specific reporting locations (W-2 box 12 TT/TP, 1099 boxes, Schedule 1-A lines), plus the 2026 nuance. Only the response shape/format is left unstated, which is a minor gap.

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% and both parameters (topic enum, tax_year 2025-2028) are fully documented in the schema, so the baseline of 3 applies. The description corroborates the year range and topic set and notes that rules differ by year, but adds no syntax or default behavior beyond what the schema states.

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 verb and resource ('Explains who can claim the ... deductions for overtime, tips and seniors') and enumerates the exact subject matter (filing status exclusions, SSN rule, FLSA, reporting boxes). This clearly distinguishes it as an explanatory/reference tool rather than a calculator, though the sibling tools (calculate_*_deduction) are never named explicitly.

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 can infer this is the tool to consult before or instead of the calculate_* siblings, and the tax_year parameter range hints at year-specific rules. There is no explicit statement of when to use this versus the four calculation siblings, nor any ordering guidance such as 'call this first to determine eligibility.'

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