suggest_vat_treatment

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

Annotations indicate readOnlyHint=true and idempotentHint=true, and the description aligns with a non-destructive suggestion tool. It adds context about the specific VAT scenarios covered and the returned structure, which complements the annotations without contradiction.

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 at about four sentences, front-loaded with the core purpose, followed by return structure, use cases, a specific rule (OSS for digital services), and a disclaimer. Every sentence adds value without 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 the complexity of EU VAT rules and the presence of a detailed output schema (implied by the description), the description covers purpose, inputs, outputs, and limitations. It is complete for an AI agent to decide to invoke the tool.

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% with detailed parameter descriptions. The description mentions the parameters (seller country, buyer country, etc.) but does not add significant new meaning beyond what the schema already provides, so the baseline score of 3 is appropriate.

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 verb 'suggests', the resource 'VAT treatment', and the scope 'under EU VAT rules', covering specific scenarios like reverse charge, OSS/IOSS. It effectively distinguishes from siblings like 'calculate_vat_amount' which compute amounts rather than treatments.

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 provides explicit use cases ('Use when building checkout VAT logic, invoice generation, or cross-border EU compliance workflows') and includes a disclaimer to verify with a tax advisor. However, it does not directly mention when not to use or suggest alternative tools, though the sibling context implies differentiation.

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