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

With no annotations, the description carries the full burden and does well: it discloses the pricing model ('priced per address, and only addresses actually screened are charged') and partial-result semantics via the facts_complete field. It omits auth requirements, rate limits, and how invalid or failed addresses are handled, but the cost and completeness disclosures are meaningful beyond the schema.

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?

Three front-loaded sentences with no filler: batch scope first, then cost, then the result-completeness signal. Each sentence carries distinct information, though the phrasing could be marginally tighter.

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 single-parameter, no-output-schema tool with no annotations, the description covers the key agent-facing concerns: batch size, cost, and how to detect incomplete screening results. Missing only failure/error behaviour and what the result payload contains beyond facts_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?

There is a single parameter with 0% schema description coverage, and the description only restates the limit ('up to 50 addresses') that maxItems already encodes. It adds no meaning about address formats or accepted chains, though the schema's items description covers those formats.

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 states a specific verb ('Screen') and resource ('addresses') plus a batch scope ('up to 50 addresses in a single call'), which implicitly distinguishes it from the singular onyx_screen sibling. It does not name onyx_screen explicitly, so an agent must infer the single-vs-batch split from the scope wording.

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 offers one usage scenario ('for example before a mass payout'), which implies the intended context, but gives no explicit when-not guidance and never names onyx_screen as the alternative for one-off lookups. Usage is implied rather than stated.

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