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

No annotations are provided, so the description must fully disclose behavior. It accurately describes the tool as a calculator with no side effects, and indicates its return format. For a simple computation tool, this is sufficient; no additional behavioral traits (e.g., destruction, auth) are applicable.

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 consists of two short, focused sentences. The first sentence defines the core functionality, while the second provides the return format and a pointer to related tools. No unnecessary words or 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 tool's low complexity (3 parameters, simple calculation), the description is complete. It covers what the tool does, how it works, what it returns, and points to related tools. The presence of an output schema (as per context signals) further reduces the burden on the description.

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 100%, with all three parameters (amount, rate, mode) having clear descriptions and enums. The description adds no extra semantic information beyond what the schema already provides, so baseline score 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?

Description clearly states verb 'Calculate French VAT (TVA)' and resource, specifies operations (convert between HT and TTC), supports all 4 French VAT rates, and lists return fields. It also distinguishes from siblings by referencing 'list_bundles' for related calculators.

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 explicitly mentions 'See list_bundles for related finance-france calculators', providing guidance on alternative tools. However, it does not explicitly state when NOT to use this tool (e.g., for non-French VAT), so it loses a point for lack of exclusionary context.

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