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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuine value beyond that by disclosing the return content: the figure is reconciled against the Sales Tax Payable book balance and broken out per month by filing state. It stops short of describing format or units.

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?

A single compact sentence with the resource front-loaded and no filler. The phrasing 'beside Sales Tax Payable in the books' is slightly oblique and could be tightened, but nothing is wasted.

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?

With no output schema, the description carries the burden of explaining returns, and it does sketch the shape — a liability figure plus a per-month status classification. For a one-optional-parameter read tool with full annotation coverage, that is close to sufficient; only the precise numeric output shape is left unstated.

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 single optional 'as_of' parameter is fully documented in the schema, including the ISO format and today-default. The description's phrase 'as of a day' merely echoes the parameter without adding new semantics, which is the expected baseline here.

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 resource and scope: sales tax owed as of a given day, plus per-month status (due/filed/paid/not filed). An agent can tell this is a computed liability view rather than a filing-record tool like tax_filings or tax_return, though the description never names those siblings to sharpen the contrast.

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 only implied — an agent infers it should call this when it wants to know how much sales tax is owed. There is no explicit when-to-use, no exclusion against tax_return/tax_filings, and no mention of prerequisites such as whether filings must exist first.

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