Export contacts as vCard text

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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds meaningful context beyond that: it returns data exactly as stored and exposes unmodeled properties, which clarifies behavioral expectations for an agent comparing against the modeled get_contact tool.

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?

Two sentences, no wasted words. The main return value is front-loaded, and the second sentence justifies the tool's unique value without repetition.

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 rich input schema, output schema, and annotations, the description is complete. It explains the raw format, exactness, and unique use cases, while the schema covers parameter semantics and the output schema covers return structure.

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?

Input schema coverage is 100%, so all three parameters are already documented with descriptions. The tool description does not add parameter-level detail, but it does not need to since the schema carries that burden.

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 states a specific outcome: raw vCard text of one or more contacts, exactly as stored. It also differentiates itself from siblings by noting it is the only way to see properties the server does not model and the only way to back up an address book.

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 clearly signals when to use this tool: when raw vCard fidelity is needed, when unmodeled properties must be accessed, or when taking a backup. It does not explicitly name alternatives or state when not to use it, but the 'only way' framing gives strong contextual guidance.

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