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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety behavior is covered. The description adds genuine provenance (IRS Rev. Proc. 2026-35), a static authoritative source, but says nothing about return format or how the 2026 versus 2027 values are presented.

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?

One sentence with a colon-delimited list is efficient, but the opening phrase 'Other 2027 inflation-adjusted tax amounts beside 2026' is grammatically awkward and leads with a contrast rather than with what the tool does. The most useful routing information is buried mid-sentence.

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?

For a two-parameter read-only lookup with full schema coverage, annotations and no output schema, this is close to sufficient, but the framing muddies the tax_year parameter: the description emphasizes 2027 'beside 2026' while the schema offers both years equally, and no guidance clarifies when to request 2026.

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 coverage is 100%, so baseline would be 3, but the description adds real meaning to the opaque enum values by spelling out what falls under 'business' (section 179, QBI) and 'other' (health FSA, kiddie tax, foreign earned income exclusion). The mapping to enum members is loose rather than explicit, which keeps it from a 5.

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 enumerates the specific figures returned (capital gains thresholds, child tax credit, AMT exemptions, section 179, etc.) and cites the source publication, so the resource is identifiable. It never states a verb and never names the siblings it is distinguished from, leaving the agent to infer that this is the lookup counterpart to get_tax_brackets and get_standard_deduction.

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?

There is no when-to-use or when-not-to-use guidance and no mention of alternatives such as calculate_federal_income_tax or get_standard_deduction. The only implicit routing cue is the enumeration of topics, which hints at what this tool covers but not at when to pick it over a sibling.

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