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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds substantive context beyond that: the two-stage cap-then-phase-out mechanic, the $100-per-$1,000 MAGI reduction, the $0 outcome for MFS, and data provenance ('copied from irs.gov in Oct 2026'). It does not describe the response shape, but there is no output schema to lean on.

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 paragraph that front-loads the cap and phase-out before the eligibility nuances. Every clause carries information, though the statutory citation and IRS sourcing note add legal flavor an agent doesn't strictly need to invoke the tool.

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 an 8-parameter calculator with 3 required fields, no output schema and annotations already covering the safety profile, the description supplies the full decision logic: caps, phase-out rate, eligibility restriction, MFS exclusion, and input-path alternatives. Nothing material is missing for a correct invocation.

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 the baseline would be 3, but the description adds real meaning: it clarifies that the three input paths (hourly rate + hours + multiplier, total_overtime_pay, qualified_overtime_premium) are alternatives, and warns that raising the multiplier to 2 does not double the qualified amount. That is interpretive guidance the schema does not supply.

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?

States a specific verb and resource ('Calculates the 2025-2028 federal deduction for qualified overtime pay'), names the governing statute and the IRS form line it mirrors, and pins the exact cap amounts. An agent can distinguish it from the tips and senior deduction siblings at a glance.

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?

Explicitly scopes what qualifies (FLSA half-time premium only, double time does not double it) and states the married-filing-separately exclusion, which is a real when-not condition. It does not explicitly route to or away from the sibling deduction tools, so it falls short of a 5.

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