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

Annotations only cover safety/idempotency; the description adds real behavioral context beyond them: deterministic output, primary-source citation, per-call cost ($0.02), and the billing guarantee that errors and unverified rules are never billed. It still doesn't explain whether the call requires a payment header or how rules-version selection interacts with as_of.

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?

Three tight sentences with zero filler, front-loaded on the core transformation. 'Exact NTA Beppyo-5 table' is unexplained jargon, but it is brief and signals sourcing rather than padding.

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?

An output schema exists, so return values need not be described, and the schema covers parameters fully. The remaining gap is that the payment-gated nature of the call (x_payment header required) is not stated in the description, which matters for a paid tool.

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 the schema already documents all 8 parameters including age, as_of, and x_payment. The description adds no parameter-level syntax or defaults beyond what the schema provides, so 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?

States a concrete transformation (annual gross -> net take-home) and names the tax components it accounts for, so the agent knows exactly what the tool computes. It does not, however, differentiate itself from close siblings like jp_bonus_net (which also handles bonus input) or jp_payroll_suite.

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 implied by the gross-to-net framing, and the x_payment behavior (omit it to get payment requirements without being charged) is useful, but there is no explicit when-to-use/when-not guidance and no named alternative for overlapping payroll siblings.

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