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

Annotations already declare this a read-only, idempotent, non-destructive, non-open-world call, so the safety profile is covered. The description adds genuinely new behavioral context in 'Calling this tool is free' (no credit/billing cost) and in explaining the semantics of the core flag, which is operational knowledge not present in the annotations.

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?

Front-loaded with the resource and then a tight clause listing each returned field; the closing sentence about cost is short and purposeful. The first sentence is dense, packing six field descriptions into one clause chain, but every clause earns its place with no filler.

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?

An output schema exists, so return values need not be explained, yet the description still supplies the cross-tool meaning of the two fields an agent must act on (code for the lists argument, core for default screening). For a zero-parameter, read-only discovery tool this leaves nothing an agent needs 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?

The tool takes zero parameters, so per the rubric the baseline is 4 with no schema-level parameter semantics to extend. The description correctly adds no parameter details and instead spends its words on output semantics.

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 concrete resource (every sanctions list screened against) and enumerates exactly what each entry carries: code, name, issuing authority, core flag, last-updated date, and entry count. It also ties the resource to the sibling tools screen_entity and screen_address, so an agent can distinguish this discovery tool from the screening tools without opening a 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?

Strong contextual guidance: it explains that 'code' is the value the lists argument of screen_entity and screen_address takes, and that 'core' lists are the ones searched when a screening names no lists — effectively telling the agent when this tool is needed. It stops short of an explicit 'call this first to resolve list codes before screening' instruction, so it is clear context rather than a full when/when-not statement.

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