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

With no annotations, the description carries the full burden. It does convey that this is a compute-only analysis rather than a mutating action, and it names the 183-day PE trigger. However, it does not disclose assumptions, whether the output is a single number or a report, or how the gross-up is rounded/applied.

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?

One dense, well-structured sentence with no filler. The core action is front-loaded, and treaty/PE details follow naturally without wordiness.

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 computation scope and parameter roles are well covered, especially with fully described schema fields. However, there is no output schema and the description does not state what the tool returns, nor does it provide explicit routing guidance versus sibling tax/finance tools. Adequate but with clear gaps.

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 100%, so the baseline is 3, but the description adds conceptual meaning: invoiceNetRequired relates to gross-up, statutoryRatePercent and treatyRatePercent map to the statutory vs treaty comparison, and daysInCountry connects to the 183-day PE trigger. It frames the parameters without repeating their schema 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?

States a specific verb ('Compute') and a distinct resource: cross-border B2B software/consulting invoice gross-up, statutory vs DTAA treaty WHT rates, W-8BEN forms, and 183-day PE triggers. This clearly separates it from sibling tools like fx_invoicing or indian_income_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 implies the tool is for cross-border B2B withholding/gross-up analysis, but it never explicitly states when to prefer it over related siblings or when not to use it. Context is present, but exclusions and alternative routing are missing.

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