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

With only readOnlyHint=true declared, the description carries real behavioral weight: it discloses tiered pricing with exact dollar amounts, that charging happens once via x402, that an invalid item is reported in place rather than failing the call, and that an all-invalid batch is refused before any charge. These are cost and failure-mode facts an agent cannot get from annotations or 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 dense sentences with zero filler: capability first, then the decision-relevant pricing tiers, then the failure semantics. The most important routing fact (batch vs. exclusion_check) is front-loaded.

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 read-only batch screening tool with no output schema, the description covers cost, partial-failure behavior, and refusal semantics well. It leaves the item field semantics and any notion of the response payload or latency unaddressed, which is a minor gap given the sibling tools and annotations cover the rest.

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 0% and the single parameter is a nested array of items whose fields (name, dob, state, npi, uei, cage) are entirely undocumented except 'ref'. The description repeats the 2-200 range that the schema already enforces via minItems/maxItems but adds nothing about what makes a valid item or how the fields are used, so it fails to compensate for the coverage gap.

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 ('Screen'), resource ('people/businesses'), and scope ('2-200 ... in one call'), and explicitly ties itself to the sibling 'exclusion_check' whose sources it shares. An agent can immediately distinguish it from exclusion_check (single) and exclusion_sources (source listing) without opening any 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?

The phrase 'in one call' plus the reference to exclusion_check implicitly routes the agent: use this when you have many items, use exclusion_check for one. However, it never states that exclusion_check is the alternative for a single item or when the batch tool should not be used, so the guidance is clear context rather than explicit when/when-not.

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