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

Annotations already indicate the operation is not read-only and not destructive, so the description adds little behavioral context beyond that. It does not state what happens to the input, how the output is returned, or any side effects. The format list is more about scope/parameters than behavior.

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, readable sentence that front-loads the tool's purpose and supported conversions. It contains minor redundancy ('vcf to excel' repeats vCard→XLSX, and 'Contact Converter —' echoes the title), but it is still compact and scannable.

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 schema fully covers the parameters, and the description clarifies the conversion domain, making the tool invocable. However, there is no output schema and the description does not explain what the tool returns or how the converted file is delivered, which is a notable gap for a conversion 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 description coverage is 100%, so the baseline is 3 even though the description adds minimal parameter detail. The description repeats valid format pairs that are already documented in the 'to' parameter description, so it does not meaningfully enhance the schema.

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 identifies the tool's specific verb ('Convert') and resource ('contact/calendar/email formats'), listing exact format pairs. This distinguishes it from the many generic convert_* siblings like convert_file and convert_document.

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 gives clear context on when to use the tool by enumerating supported conversions (vCard↔CSV, vCard→XLSX, ICS→JSON/CSV, MSG→EML, EML→PDF). It does not explicitly name alternatives or exclusions, but the domain is specific enough for an agent to route appropriately.

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