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

No annotations exist, so the description bears the full burden. It discloses the methodology basis ('Wayfair ruling') and that current thresholds are used, which tells the agent the result is rule-based and up to date. However, it does not describe the output form, the role of the two numeric inputs in the threshold check, or whether the tool is an estimate/legal advice, leaving meaningful behavioral gaps.

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 short sentences, with the main purpose first and the two supporting facts (Wayfair basis and threshold recency) each earning their place. No filler or repetition.

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?

The description covers the core purpose and methodology but leaves notable context gaps: no output schema, no annotations, and no statement about how statesWithSales affects the result or what happens if only totalSales is provided. For a simple two-parameter tool this is adequate but not 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 100% for both totalSales and statesWithSales, so the schema already explains the parameters. The tool description only references 'thresholds' and does not add further meaning about the numeric inputs beyond what the schema provides, so the schema-heavy baseline of 3 applies.

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?

Opens with a specific verb ('Check') and a concrete resource ('which US states you have economic nexus in'), then anchors it to 'sales tax collection', 'Wayfair ruling', and 'Latest CDN thresholds.' This clearly differentiates it from sibling rate-lookup tools like get_sales_tax_rate or payment tools like calculate_quarterly_tax.

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 supplies a clear use context: determining economic nexus obligations for sales tax. It does not explicitly list exclusions or alternatives, but the context is specific enough that an agent can select it over sibling tax-rate and filing tools.

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