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

Annotations declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context beyond that: alias matching is covered, external authoritative lists are queried, and the pricing model ($0.01 USDC per call, charged only on success) is disclosed — a cost detail annotations never carry. It stops short of describing the response shape or match scoring.

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 carrying purpose, both data sources, and the pricing condition, with the primary function front-loaded and no filler. Every clause 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 two-parameter read-only lookup with no output schema, the description covers what is screened, against which authority, and the cost implications. What is missing is only a hint at what a returned result looks like (match/no-match, score), which is a minor gap given annotations already cover safety and openness.

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 coverage is 100%, so both parameters are already documented. The description does add the specific data source behind the optional EIN check (IRS Publication 78) and clarifies both name and aliases are screened, which is modest added meaning over the schema — responsive to the baseline-3 expectation for high-coverage schemas.

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) plus two concrete authoritative data sources (OFAC SDN with aliases, IRS Publication 78 for EIN nonprofit confirmation). This is clearly distinguishable from all siblings, which cover unrelated domains like product recalls, VIN decoding, and contractor lookups.

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 description makes the use case clear: sanctions screening of a person or business name, with an optional nonprofit status confirmation via EIN. It does not name when-not to use it or point to a sibling alternative, but the domain is narrow enough that no ambiguity remains.

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