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

With no annotations available, the description properly takes on the burden: it states the output behavior, the categories produced, and a non-obvious calculation rule (NYC taxes are several times upstate rates and one NYC tax doesn't exist outside the five boroughs). It doesn't discuss side effects, auth, or limitations, but for a read-only estimation tool the disclosed behavior is largely sufficient.

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 sentences, with the purpose and resource front-loaded, output summarized in the second sentence, and the critical NYC caveat placed last. No filler; each sentence earns its place.

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 12-parameter tool with no output schema and only 17% schema description coverage, the description covers purpose, output, and the most important jurisdiction-specific rule, but it omits guidance for the many optional parameters and the CEMA option for NY refinances. A competent agent could use the schema descriptions for isNYC and cemaEnabled, so the main gap is the optional fee/tax inputs; overall it is adequate but not fully complete.

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 only 17% (isNYC and cemaEnabled have descriptions), so the tool description needed to compensate for the other 10 parameters. It reinforces isNYC and names output categories, but it doesn't clarify the basis for percent parameters (e.g., originationFeePercent, brokerFeePercent), when optional inputs like existingMortgageBalance are needed, or how optional fields interact with the estimate. The bare parameter names are partially self-explanatory, but the description adds little semantic precision beyond the schema.

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 opens with 'Itemize commercial closing costs for a New York or Florida transaction' — a specific verb and resource — and enumerates cost categories (lender, title, government, prepaid, third-party). It also states the output ('Returns every line item plus totals'), making the tool's scope and deliverable unambiguous relative to siblings like calculate_payment or analyze_cash_out_refinance.

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?

It gives clear operating context (NY or FL commercial transactions) and a mandatory NYC/upstate distinction, but it never explicitly says when to prefer this tool over calculate_payment, compare_loan_offers, or other siblings. The use case is implied by the named resource ('closing costs') rather than stated as an explicit when/when-not rule.

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