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

Annotations cover the safety profile (readOnly, idempotent, non-destructive), and 'pure arithmetic in USD' reinforces deterministic, no-network behavior consistent with openWorldHint=false. It also discloses the output verdict set, though it never states the fee rate or whether fees are configurable.

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?

Two tight sentences with zero filler; the output verdicts and the sibling routing are both front-loaded where an agent needs them.

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-param arithmetic tool with no output schema, the description supplies the output categories and the upstream dependency. The only gap is the unspecified fee model, which could matter for trust in the verdict.

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% with both parameters documented, so the schema already carries the semantics. The description restates them in prose ('expected sale price', 'what the user would pay') and adds only the USD unit reminder – baseline 3.

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 computation (seller's net after eBay fees) plus the exact verdict categories returned (worth it / thin / pass) for a given sale price and cost. It is clearly distinguishable from siblings like price_item, which it explicitly defers to.

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?

Gives an explicit prerequisite: 'use price_item first when the sale price is unknown,' naming the alternative tool and the condition that selects it. No when-not guidance beyond that, but the routing is concrete.

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