VAT code card

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is known. The description adds 'Defaults to JSON,' but this is redundant with the schema's format parameter description. The pipe-separated support is also already documented in the vat_code parameter. No additional behavioral context (e.g., return structure, authorization) is disclosed.

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 a single, front-loaded sentence with no unnecessary words. It efficiently states the action, resource, and a key usage example. This is an excellent model of conciseness, even if it sacrifices depth.

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?

With 8 parameters and no output schema, the description is quite minimal. The schema covers parameters and annotations cover safety, but the description does not explain what an 'account card' contains or what the response looks like. For a simple read-only tool, this is minimally viable but leaves room for improvement.

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%, so the schema fully documents all 8 parameters. The description does not add new meaning beyond what the schema provides; it merely repeats the multiple-vat-code example already in the vat_code parameter description. Thus it neither improves nor harms parameter understanding.

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: 'Return the account card for a VAT code.' It uses a specific verb and resource, and the pipe-separated example ('V0|V80') clarifies multiple-code handling. This distinguishes it from sibling tools like banana_vat_balance or banana_vat_description, which serve different VAT-related purposes.

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—use this tool when you need a VAT code card—but it provides no explicit when-to-use guidance or mention of alternatives. There are no exclusions or scenarios where another tool would be preferred, leaving the agent to infer usage from the purpose alone.

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