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

Annotations already mark the tool as read-only and non-destructive. The description adds useful behavioral context beyond that: it states the return shape ('every line item plus totals') and explains why NYC vs. upstate matters, including the existence of a tax that only applies in the five boroughs. Nothing contradicts 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?

The description is two sentences with no filler. The first sentence front-loads the purpose and scope; the second delivers a critical input constraint with reasoning. Every clause 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?

Given the 12-parameter schema and no output schema, the description compensates well by indicating the output content and highlighting the most important conditional input (isNYC). It could be more complete by explaining how optional inputs like insurance or property tax affect the estimate, but the core invocation guidance is present and sufficient.

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%, so the description must compensate. It does clarify the state parameter by scoping to NY/FL and adds meaning to isNYC by mandating the NYC distinction serious. However, most numeric parameters (loanAmount, interestRate, annualInsurance, existingMortgageBalance, etc.) are left unexplained by the description and rely on their names and ranges for meaning, so compensation is incomplete.

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 a specific verb and resource: 'Itemize commercial closing costs' for a New York or Florida transaction candidates. It lists concrete cost categories (lender, title, government, prepaid, third-party) and says the tool returns line items plus totals, clearly separating it from sibling analytics like calculate_payment or size_loan.

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?

The description gives clear context for when the tool applies — estimating NY or FL commercial closing costs — and adds a mandatory usage condition for New York: the agent MUST specify whether the property is in NYC. It does not explicitly say 'use this instead of X' or describe when not to use it, so it stops 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.