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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful real-world context: walk-ins are generally accepted, and the requisition is delivered by email once physician authorization exists. This tells an agent about expected workflow and caveats without contradicting the annotations.

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, front-loaded with the core action and result fields, followed by relevant caveats. Every clause earns its place with no redundant filler.

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 simple read-only lookup with one required parameter and full schema documentation, the description covers the purpose, returned fields, and key process caveats (walk-ins, authorization email). Nothing essential for selecting or invoking the tool 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?

Schema coverage is 100%, and the description does not need to restate parameter details; the schema already explains zip format, defaults, and radius snapping. The description adds only a general link between labs and the enum values, so it stays at the baseline for fully documented schemas.

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 uses a specific verb ('Find') plus a precise resource (Quest Diagnostics, Labcorp and BioReference patient service centers), a location qualifier (near a US ZIP code), and expected result fields (address, distance, phone, hours). This clearly distinguishes it from the sibling tools, none of which target draw-site location lookup.

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 makes the invocation context obvious: whenever a patient needs draw sites near a ZIP code, this is the tool. It does not explicitly name when-not-to-use or a competing sibling, but none of the listed siblings perform this function, so the absence is not a material gap.

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