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

Annotations already establish that this is read-only, idempotent, and non-destructive, so the description does not need to restate those traits. It adds useful context about the result content and the provenance of labId, but it does not disclose additional behavioral aspects like error conditions or data freshness. With annotations covering the safety profile, a score of 3 is appropriate.

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 sentence that front-loads the specific details returned and ends with the key usage dependency. There is no filler or redundant restatement of the tool name or schema.

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?

For a one-parameter, read-only tool, the description, schema, and annotations cover everything an agent needs: what data comes back, where the labId originates, and the safety profile. Since there is no output schema, the explicit field list is valuable and nothing critical is missing.

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?

The schema already describes labId as 'The labId returned by find_labs' with 100% coverage. The description reinforces this provenance, adding marginal semantic value but not carrying the parameter-documentation 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 clearly identifies the resource as 'one Hera partner lab' and enumerates the exact details returned: address, phone, hours, walk-in policy, at-home collection, visit instructions, and prices. It also differentiates from find_labs by stating that labId comes from find_labs, indicating this is the single-lab lookup after search.

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 statement 'labId comes from find_labs' explicitly routes an agent to call find_labs first to obtain the identifier. It provides clear context for when to use this tool, though it does not explicitly mention hera_facts or state when not to use this tool.

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