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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description does not need to restate those. It usefully adds that the result includes treaty rate, filing form, and deadline, and clarifies input formats for country codes and payment_date; it still does not describe error behavior or eligibility edge cases.

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 tightly written sentences with no wasted language. The core purpose is front-loaded, and the format details are placed after the main behavior.

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 14-parameter tax estimation tool with low schema coverage and no output schema, the description is too thin. It gives useful high-level output components and two input formats, but does not explain the optional parameters that materially affect treaty-rate and refund eligibility calculations.

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 14%, so the description carries a heavy burden for 14 parameters. It clarifies ISO alpha-2 country codes and YYYY-MM-DD payment_date, but leaves most parameters (entity_type, holding_pct, holding_months, withheld_rate_pct, is_franked, is_portfolio_interest, etc.) without added semantic guidance.

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 states a specific verb and resource: estimating reclaimable withholding tax on one dividend or interest payment for a source/residence country pair. It also names the key outputs (treaty rate, filing form, deadline), though it does not explicitly differentiate this tool from siblings like estimate_dividends or get_deadline.

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 its domain but gives no explicit guidance on when to use this tool versus get_deadline or estimate_dividends. There are no stated exclusions, prerequisites, or alternative-routing instructions.

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