thai_calculate_vat

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, indicating a safe, read-only calculation. The description adds valuable context about the return format (JSON with base, vat, total, and optional withholding), which goes beyond annotations without contradicting them.

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 extremely concise: two short sentences and a bullet list for returns. It front-loads the core action and provides structured return information without any superfluous words.

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 tool is simple, and the explanation of return values is adequate. The annotation and output schema (indicated as present) fill in remaining context. The description does not cover edge cases, but for a straightforward tax calculator, this level of detail is 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?

The input schema already provides descriptions for all four parameters (amount, mode, rate, withholding_rate_percent), effectively covering their meanings. The description adds little parameter-specific detail beyond the schema, so a baseline score of 3 is appropriate given the high schema description coverage.

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 clearly states the tool's function: 'Add or extract 7% Thai VAT, and optionally compute withholding tax.' It specifies the verb and resource (VAT and withholding tax), and the sibling tools are all distinct (baht to text, date conversion, etc.), so there is no ambiguity or overlap.

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 usage for VAT calculations but does not explicitly provide when-to-use or when-not-to-use guidelines. However, the sibling tools are unrelated, so no exclusions are necessary, and the context is clear enough for an AI to infer appropriate use.

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