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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real value by enumerating the returned fields, which is important since no output schema exists, though it says nothing about error behavior for an invalid or stale labRef.

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 tight sentences that front-load the returned data and end with the calling instruction. Every clause carries information, with only minor redundancy against the schema's labRef description.

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 no output schema, the description usefully enumerates the returned fields, and annotations cover the safety profile; a two-parameter, zero-required tool is well served. A brief note on failure cases for an invalid labRef would make it fully complete.

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 both labId and labRef are already documented in the schema, including the deprecation note. The description only restates that labRef comes from find_labs, adding little beyond the structured fields — baseline 3.

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?

States a specific verb+resource (get details for one Hera partner lab) and enumerates the exact content returned: address, phone, hours, walk-in policy, at-home collection, visit instructions and prices. The 'Pass the labRef returned by find_labs' clause cleanly differentiates it from the sibling find_labs.

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?

Explicitly instructs to pass the labRef returned by find_labs, which establishes the correct call order after a search. It stops short of stating when not to use it or what to do if a labRef is unknown, but the usage context is clear.

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