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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: it discloses the one-best-match-per-name deduplication rule, the threshold-or-nothing outcome, the compact return shape, and the summary count. It stops short of noting freshness of the mirror or that EU lists may be absent except via the parenthetical.

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?

A single sentence with the batch limit front-loaded and no filler, though the stacked parenthetical listing the mirror sources makes it denser than necessary given the lists enum already enumerates those sources.

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?

There is no output schema, so the description must sketch return values, and it does so adequately with "only the best possible match per name (or no match at the threshold) in compact form, with a summary count." For a read-only, closed-world screening tool across five well-documented parameters, this leaves little an agent needs that 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 description coverage is 100%, so the schema carries parameter documentation and the baseline is 3. The description adds only marginal meaning beyond it: the per-name best-match/threshold interplay clarifies what min_score actually gates, but name-count limits and list composition are already fully specified in the schema.

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 names a specific verb and resource ("Screens up to 25 names") and explicitly anchors it against the sibling screen_party ("the same list mirrors as screen_party"), so an agent can tell batch screening apart from single-party screening without opening either schema.

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?

Batch scope (up to 25 names in one call) implies when to reach for this tool over screen_party, and the reference to list_status hints at a prerequisite check. However, there is no explicit "use this instead of screen_party when you have multiple names" statement or exclusion guidance, so the routing is left to inference.

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