Thai VAT & Withholding Tax Reference

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context: no arguments, returns structured JSON with specific fields (vat, withholdingTax, disclaimers), and is safe to call. No contradictions.

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 concise with three front-loaded paragraphs: purpose, behavior, and usage guidelines. Every sentence adds value, no redundancy.

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?

Given zero parameters and no output schema, the description fully covers what the tool returns (structured JSON with vat, withholdingTax, disclaimers) and its limitations. No gaps remain.

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?

No parameters exist, and the description explicitly states 'No arguments.' The input schema is empty with 100% coverage, so the description adds the necessary clarity for a parameterless tool.

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 provides a reference card for Thai VAT and withholding tax basics. It identifies the specific resource and action, and its purpose is distinct from sibling tools like thai_address_normalize or thai_company_lookup.

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?

Explicitly states when to use: computing invoice amounts, checking VAT registration, or explaining withholding certificates. Also provides a clear exclusion: 'not tax advice' and advises verification with the Revenue Department. This fully guides agent selection.

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