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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower; the description still adds real behavior: it explains that only offers 'still open' count (expiration filtering), that the best offer serves as the floor for a dealer's number, that equity may be negative, and that tax savings apply only 'where the state credits it.' These are meaningful computational semantics not present in the annotations.

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?

It is a single sentence with no filler, and the input premise is front-loaded ('From written trade-in offers and the payoff'). However, the trailing tax clause is heavily nested with commas and parentheticals, making it noticeably harder to parse than it needs to be for three outputs.

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 calculation tool with no output schema, the description says what is computed but not the shape of the result (fields, currency, whether the tax saving is a separate line) or edge behavior such as all offers being expired. Annotations cover the safety profile and the schema is rich, so this is a gap rather than a failure.

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 88%, so the baseline is 3, and the description adds linkage the schema does not: payoff is used to derive equity, and the pair (state, vehicle_price) unlocks the tax-savings output only where the state allows a credit. The 'best offer still open' phrasing also implies the expires field drives filtering, adding meaning beyond the per-field text.

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 names the resource (trade-in position) and the three concrete outputs it derives: the best still-open offer as a floor for a dealer's trade number, equity/negative equity, and conditional sales-tax savings. It is specific enough that an agent can tell this apart from quote-comparison siblings, though it never names an alternative or uses an explicit verb like 'computes.'

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 statement of when to call this versus check_quote, compare_quotes, or payoff_plan, and no prerequisite guidance beyond the implied 'you need written offers.' The conditional clause 'with a state and vehicle price' hints at optional inputs but is not framed as usage guidance.

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