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

The annotations already establish readOnly, closed-world, idempotent, and non-destructive behavior. The description adds important behavioral context beyond that: results include lead counts and verified email counts, each list has a page, lists are emailed from that page, and this tool cannot request or download a list.

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 front-loaded with the core purpose, then immediately states scope limits and return behavior in three efficient sentences. There is no redundant or wasted text.

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?

Although there is no output schema, the description explains the return shape well enough: best-matching lists with lead counts, verified email counts, and each list's page. It also covers the critical limitation that the tool cannot request or download lists.

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%, so all three parameters are already well documented in the input schema. The description reinforces the industry/role/country filtering intent, but does not add syntax, defaults, or edge-case meaning beyond what the schema provides.

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 gives a specific verb and resource: it searches WarmInboxes' own catalogue of about 1,000 free B2B lead lists by industry, role, and country. It also explicitly distinguishes this from web search or any other database, so the agent can tell what the tool is and is not.

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?

It clearly states when the tool applies and gives strong exclusions: it does not search the web or other databases, and it cannot request or download a list. It does not name a sibling alternative, so it falls just short of fully explicit alternative routing.

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