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

The description adds substantial behavioral context beyond the annotations, including the 25-address limit, per-address result behavior, pricing model, prepaid header requirement, free-call allowance, and lack of wallet/API key requirement. This meaningfully informs an agent about side effects and prerequisites.

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 capability and then provides use-case, input, and pricing context. The 'Required input: addresses' sentence is mildly redundant with the schema and earlier phrasing, but overall every sentence earns its place.

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 tool with a rich output schema and strong annotations, the description is complete. It covers capacity, expected results, billing, authentication, and access requirements. The output schema relieves the description from needing to detail return values.

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?

The schema already covers the comma-separated format for the single parameter, so the baseline is 3. The description adds the crucial up-to-25 limit and explicitly identifies 'addresses' as required input, going slightly beyond schema information.

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 and resource ('Screen up to 25 addresses against OFAC at once') and clearly differentiates this from sibling tools like 'sanctions' by emphasizing batch processing and counterparty-list vetting. The expected output is also stated: a result for each address plus the flagged subset.

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 provides clear context for when to use the tool ('vetting whole counterparty lists in one call') and practical requirements like the comma-separated list and cost. However, it does not explicitly say when not to use it or name a single-address alternative like 'sanctions'.

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